Android ImageView Zoom-in and Zoom-Out

Question

I want to Zoom-in and Zoom-out an Android ImageView  I tried most of the samples but in all of them the image in the ImageView itself is getting Zoomed-in and Zoomed-out  while I want to Zoom-in and Zoom-out the ImageView  I want to increase the ImageView width and height while Zooming-in and reduce the ImageView width and height while Zooming-out  How do I achieve that

User · Answer

Simple way   PhotoViewAttacher pAttacher  pAttacher   new PhotoViewAttacher Your Image View   pAttacher update      Add below line in build gradle    compile  com commit451 PhotoView 1 2 4

User · Answer

Please follow the below class  that is used for Zoom in and Zoom Out for ImageView   import android app Activity  import android graphics Matrix  import android graphics PointF  import android os Bundle  import android util Log  import android view MotionEvent  import android view View  import android view View OnTouchListener  import android widget ImageView   public class ZoomInZoomOut extends Activity implements OnTouchListener        private static final String TAG    Touch        SuppressWarnings  unused       private static final float MIN ZOOM   1f MAX ZOOM   1f          These matrices will be used to scale points of the image     Matrix matrix   new Matrix        Matrix savedMatrix   new Matrix            The 3 states  events  which the user is trying to perform     static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      int mode   NONE          these PointF objects are used to record the point s  the user is touching     PointF start   new PointF        PointF mid   new PointF        float oldDist   1f           Called when the activity is first created          Override     public void onCreate Bundle savedInstanceState                 super onCreate savedInstanceState           setContentView R layout main           ImageView view    ImageView  findViewById R id imageView           view setOnTouchListener this               Override     public boolean onTouch View v  MotionEvent event                 ImageView view    ImageView  v          view setScaleType ImageView ScaleType MATRIX           float scale           dumpEvent event              Handle touch events here             switch  event getAction    amp  MotionEvent ACTION MASK                         case MotionEvent ACTION DOWN       first finger down only                                                 savedMatrix set matrix                                                   start set event getX    event getY                                                     Log d TAG   mode DRAG       write to LogCat                                                 mode   DRAG                                                  break               case MotionEvent ACTION UP     first finger lifted              case MotionEvent ACTION POINTER UP     second finger lifted                                                  mode   NONE                                                  Log d TAG   mode NONE                                                    break               case MotionEvent ACTION POINTER DOWN     first and second finger down                                                  oldDist   spacing event                                                   Log d TAG   oldDist     oldDist                                                   if  oldDist  gt  5f                                                        savedMatrix set matrix                                                       midPoint mid  event                                                       mode   ZOOM                                                      Log d TAG   mode ZOOM                                                                                                      break               case MotionEvent ACTION MOVE                                                   if  mode    DRAG                                                                                                          matrix set savedMatrix                                                       matrix postTranslate event getX   - start x  event getY   - start y      create the transformation in the matrix  of points                                                                                                    else if  mode    ZOOM                                                                                                             pinch zooming                                                     float newDist   spacing event                                                       Log d TAG   newDist     newDist                                                       if  newDist  gt  5f                                                                                                                 matrix set savedMatrix                                                           scale   newDist   oldDist     setting the scaling of the                                                                                        matrix   if scale  gt  1 means                                                                                        zoom in   if scale  lt  1 means                                                                                        zoom out                                                         matrix postScale scale  scale  mid x  mid y                                                                                                                                                           break                     view setImageMatrix matrix      display the transformation on screen          return true     indicate event was handled                      --------------------------------------------------------------------------        Method  spacing Parameters  MotionEvent Returns  float Description         checks the spacing between the two fingers on touch        ----------------------------------------------------              private float spacing MotionEvent event                 float x   event getX 0  - event getX 1           float y   event getY 0  - event getY 1           return  float  Math sqrt x   x   y   y                        --------------------------------------------------------------------------        Method  midPoint Parameters  PointF object  MotionEvent Returns  void        Description  calculates the midpoint between the two fingers        ------------------------------------------------------------              private void midPoint PointF point  MotionEvent event                 float x   event getX 0    event getX 1           float y   event getY 0    event getY 1           point set x   2  y   2                  Show an event in the LogCat view  for debugging        private void dumpEvent MotionEvent event                 String names        DOWN    UP    MOVE    CANCEL    OUTSIDE   POINTER DOWN    POINTER UP    7     8     9              StringBuilder sb   new StringBuilder            int action   event getAction            int actionCode   action  amp  MotionEvent ACTION MASK          sb append  event ACTION    append names actionCode             if  actionCode    MotionEvent ACTION POINTER DOWN    actionCode    MotionEvent ACTION POINTER UP                         sb append   pid    append action  gt  gt  MotionEvent ACTION POINTER ID SHIFT               sb append                          sb append               for  int i   0  i  lt  event getPointerCount    i                           sb append      append i               sb append   pid    append event getPointerId i                sb append       append  int  event getX i                sb append      append  int  event getY i                if  i   1  lt  event getPointerCount                    sb append                          sb append               Log d  Touch Events ---------   sb toString

User · Answer

Make two java classes  Zoom class  import android content Context  import android graphics Canvas  import android graphics drawable Drawable  import android view KeyEvent  import android view View  import android widget Button  import android widget ImageButton   public class Zoom extends View        private Drawable image      ImageButton img img1      private int zoomControler 20       public Zoom Context context               super context                image context getResources   getDrawable R drawable j                 image context getResources   getDrawable R drawable icon                setFocusable true               Override     protected void onDraw Canvas canvas            super onDraw canvas              here u can control the width and height of the images         this line is very important         image setBounds  getWidth   2 -zoomControler   getHeight   2 -zoomControler   getWidth   2  zoomControler   getHeight   2  zoomControler           image draw canvas               Override     public boolean onKeyDown int keyCode  KeyEvent event                 if keyCode  KeyEvent KEYCODE DPAD UP                          zoom in                     zoomControler  10                            if keyCode  KeyEvent KEYCODE DPAD DOWN                          zoom out                     zoomControler- 10                            if zoomControler lt 10                       zoomControler 10                             invalidate                return true            make second class  import android app Activity  import android os Bundle   public class Zoomexample extends Activity          Called when the activity is first created          Override    public void onCreate Bundle icicle           super onCreate icicle          setContentView new Zoom this

User · Answer

just use this class   TouchImageView

User · Answer

This code works and implement the double tap to return to original image size   1st step - In your xml layout put this    lt com            TouchImageView     android id    id action infolinks splash      android layout width  match parent      android layout height  match parent      android src   mipmap myinfolinks splash      android layout gravity  center      android gravity  center      android scaleType  fitCenter      android contentDescription   string aboutSupport description image   gt    2nd step- Create a file  TouchImageView java  with the TouchImageView class   import android content Context  import android graphics Bitmap  import android graphics BitmapFactory  import android graphics Matrix  import android graphics PointF  import android util AttributeSet  import android view GestureDetector  import android view MotionEvent  import android view ScaleGestureDetector  import android view View  import android widget ImageView   public class TouchImageView extends ImageView        Matrix matrix          We can be in one of these 3 states     static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      int mode   NONE          Remember some things for zooming     PointF last   new PointF        PointF start   new PointF        float minScale   1f      float maxScale   3f      float   m      float redundantXSpace  redundantYSpace  origRedundantXSpace  origRedundantYSpace       int viewWidth  viewHeight      static final int CLICK   3      static final float SAVE SCALE   1f      float saveScale   SAVE SCALE      protected float origWidth  origHeight      int oldMeasuredWidth  oldMeasuredHeight      float origScale  bottom  origBottom  right  origRight       ScaleGestureDetector mScaleDetector      GestureDetector mGestureDetector       Context context       public TouchImageView Context context            super context           sharedConstructing context              public TouchImageView Context context  AttributeSet attrs            super context  attrs           sharedConstructing context              private void sharedConstructing Context context            super setClickable true           this context   context          mScaleDetector   new ScaleGestureDetector context  new ScaleListener             matrix   new Matrix            m   new float 9           setImageMatrix matrix           setScaleType ScaleType MATRIX            setOnTouchListener new OnTouchListener                   Override             public boolean onTouch View v  MotionEvent event                     boolean onDoubleTapEvent   mGestureDetector onTouchEvent event                   if  onDoubleTapEvent                           Reset Image to original scale values                     mode   NONE                      bottom   origBottom                      right   origRight                      last   new PointF                        start   new PointF                        m   new float 9                       saveScale   SAVE SCALE                      matrix   new Matrix                        matrix setScale origScale  origScale                       matrix postTranslate origRedundantXSpace  origRedundantYSpace                       setImageMatrix matrix                       invalidate                        return true                                     mScaleDetector onTouchEvent event                   PointF curr   new PointF event getX    event getY                      switch  event getAction                          case MotionEvent ACTION DOWN                          last set curr                           start set last                           mode   DRAG                          break                       case MotionEvent ACTION MOVE                          if  mode    DRAG                                float deltaX   curr x - last x                              float deltaY   curr y - last y                              float fixTransX   getFixDragTrans deltaX  viewWidth  origWidth   saveScale                               float fixTransY   getFixDragTrans deltaY  viewHeight  origHeight   saveScale                               matrix postTranslate fixTransX  fixTransY                               fixTrans                                last set curr x  curr y                                                     break                       case MotionEvent ACTION UP                          mode   NONE                          int xDiff    int  Math abs curr x - start x                           int yDiff    int  Math abs curr y - start y                           if  xDiff  lt  CLICK  amp  amp  yDiff  lt  CLICK  performClick                            break                       case MotionEvent ACTION POINTER UP                          mode   NONE                          break                                     setImageMatrix matrix                   invalidate                    return true     indicate event was handled                                     mGestureDetector   new GestureDetector context  new GestureDetector SimpleOnGestureListener                  Override             public boolean onDoubleTapEvent MotionEvent e                    return true                                       public void setMaxZoom float x            maxScale   x             private class ScaleListener extends ScaleGestureDetector SimpleOnScaleGestureListener            Override         public boolean onScaleBegin ScaleGestureDetector detector                mode   ZOOM              return true                      Override         public boolean onScale ScaleGestureDetector detector                float mScaleFactor   detector getScaleFactor                  float mScaleFactor    float  Math min Math max  95f  detector getScaleFactor     1 05               float origScale   saveScale              saveScale    mScaleFactor              if  saveScale  gt  maxScale                    saveScale   maxScale                  mScaleFactor   maxScale   origScale                else if  saveScale  lt  minScale                    saveScale   minScale                  mScaleFactor   minScale   origScale                             right   viewWidth   saveScale - viewWidth -  2   redundantXSpace   saveScale               bottom   viewHeight   saveScale - viewHeight -  2   redundantYSpace   saveScale                if  origWidth   saveScale  lt   viewWidth    origHeight   saveScale  lt   viewHeight                  matrix postScale mScaleFactor  mScaleFactor  viewWidth   2  viewHeight   2               else                 matrix postScale mScaleFactor  mScaleFactor  detector getFocusX    detector getFocusY                  fixTrans                return true                       void fixTrans             matrix getValues m           float transX   m Matrix MTRANS X           float transY   m Matrix MTRANS Y            float fixTransX   getFixTrans transX  viewWidth  origWidth   saveScale           float fixTransY   getFixTrans transY  viewHeight  origHeight   saveScale            if  fixTransX    0    fixTransY    0              matrix postTranslate fixTransX  fixTransY              float getFixTrans float trans  float viewSize  float contentSize            float minTrans  maxTrans           if  contentSize  lt   viewSize                minTrans   0              maxTrans   viewSize - contentSize            else               minTrans   viewSize - contentSize              maxTrans   0                     if  trans  lt  minTrans              return -trans   minTrans          if  trans  gt  maxTrans              return -trans   maxTrans          return 0             float getFixDragTrans float delta  float viewSize  float contentSize            if  contentSize  lt   viewSize                return 0                    return delta              Override     protected void onMeasure int widthMeasureSpec  int heightMeasureSpec            super onMeasure widthMeasureSpec  heightMeasureSpec           viewWidth   MeasureSpec getSize widthMeasureSpec           viewHeight   MeasureSpec getSize heightMeasureSpec                          Rescales image on rotation                    if  oldMeasuredHeight    viewWidth  amp  amp  oldMeasuredHeight    viewHeight    viewWidth    0    viewHeight    0  return           oldMeasuredHeight   viewHeight          oldMeasuredWidth   viewWidth           if  saveScale    1                   Fit to screen              float scale              int bmWidth bmHeight               Bitmap bm   BitmapFactory decodeResource context getResources    R mipmap myinfolinks splash               bmWidth   bm getWidth                bmHeight   bm getHeight                 int  w   bmWidth              int  h   bmHeight              viewWidth   resolveSize w  widthMeasureSpec               viewHeight   resolveSize h  heightMeasureSpec                float scaleX    float  viewWidth    float  bmWidth              float scaleY    float  viewHeight    float  bmHeight              scale   Math min scaleX  scaleY               matrix setScale scale  scale               saveScale   SAVE SCALE              origScale   scale                  Center the image             redundantYSpace    float  viewHeight -  scale    float  bmHeight               redundantXSpace    float  viewWidth -  scale    float  bmWidth               redundantYSpace     float  2              redundantXSpace     float  2               origRedundantXSpace   redundantXSpace              origRedundantYSpace   redundantYSpace               matrix postTranslate redundantXSpace  redundantYSpace                origWidth   viewWidth - 2   redundantXSpace              origHeight   viewHeight - 2   redundantYSpace               right   viewWidth   saveScale - viewWidth -  2   redundantXSpace   saveScale               bottom   viewHeight   saveScale - viewHeight -  2   redundantYSpace   saveScale               origRight   right              origBottom   bottom               setImageMatrix matrix                     fixTrans              And finally  make the call in your main activity   TouchImageView imgDisplay    TouchImageView  messageView findViewById R id id myImage   imgDisplay setMaxZoom 2f   imgDisplay setImageResource R drawable myImage     I saw lots of code and after my adjustments it s working  Enjoy

User · Answer

I needed something similar  but needed the ability to get the dimensions easily and also drag drop   I based this off of the answer  Nicolas Tyler gave and modified it from there     The features are pinch zoom in out  long press to vibration highlighted drag drop     To use it add this CustomZoomView class to your project   public class CustomZoomView extends View implements View OnTouchListener  View OnLongClickListener    private Paint mPaint   Vibrator v   static final int NONE   0  static final int DRAG   1  static final int ZOOM   2  static final int MOVE   3   private int mode   NONE   Rect src  Rect mTempDst   new Rect    Rect dst   new Rect     Bitmap mBitmap   private int mBitmapWidth   -1  private int mBitmapHeight   -1   private PointF mStartPoint   new PointF    private PointF mMiddlePoint   new PointF    private PointF mStartDragPoint   new PointF    private PointF mMovePoint   new PointF     private float oldDist   1f  private float scale  private float oldEventX   0  private float oldEventY   0  private float oldStartPointX   0  private float oldStartPointY   0  private int mViewWidth   -1  private int mViewHeight   -1   private boolean mDraggable   false    public CustomZoomView Context context        this context  null  0       public CustomZoomView Context context  AttributeSet attrs        this context  attrs  0      public CustomZoomView Context context  AttributeSet attrs  int defStyle        super context  attrs  defStyle       this setOnTouchListener this       this setOnLongClickListener this       v    Vibrator  context getSystemService Context VIBRATOR SERVICE       mPaint   new Paint        mPaint setColorFilter new PorterDuffColorFilter Color argb 100 255 255 255   PorterDuff Mode SRC IN        Override public void onSizeChanged int w  int h  int oldw  int oldh        super onSizeChanged w  h  oldw  oldh       mViewWidth   w      mViewHeight   h     public void setBitmap Bitmap bitmap        if  bitmap    null             src   new Rect            src left   0          src top   0          src right   bitmap getWidth            src bottom   bitmap getHeight            mBitmap   bitmap           mBitmapWidth   bitmap getWidth     1          mBitmapHeight   bitmap getHeight     1           dst   new Rect            dst left    mViewWidth   2  -  mBitmapWidth   2           dst top    mViewHeight   2  -  mBitmapHeight   2           dst right    mViewWidth   2     mBitmapWidth   2           dst bottom    mViewHeight   2     mBitmapHeight   2               Override public boolean onTouch View v  MotionEvent event         switch  event getAction    amp  MotionEvent ACTION MASK            case MotionEvent ACTION DOWN              mStartPoint set event getX    event getY                 mStartDragPoint set event getX    event getY                 mTempDst set dst left  dst top  dst right  dst bottom               mode   DRAG              break          case MotionEvent ACTION POINTER DOWN              oldDist   spacing event               if  oldDist  gt  10f                    midPoint mMiddlePoint  event                   mode   ZOOM                            break          case MotionEvent ACTION UP          case MotionEvent ACTION POINTER UP              if  mode    ZOOM                    mBitmapWidth   dst right - dst left                  mBitmapHeight   dst bottom - dst top                            mode   NONE              break          case MotionEvent ACTION MOVE              if  mode    DRAG                    mMovePoint x   event getX                    mMovePoint y   event getY                    drag event                 else if  mode    ZOOM                    zoom event                 else if  mode    MOVE                    move event                             break             return false     public void move MotionEvent event         int xChange    int   event getX   - mStartPoint x       int yChange    int   event getY   - mStartPoint y        dst left   mTempDst left    xChange       dst top   mTempDst top    yChange        dst right   mTempDst right    xChange       dst bottom   mTempDst bottom    yChange        invalidate        public void drag MotionEvent event         float eventX   event getX        float eventY   event getY        float spacingX   eventX - mStartDragPoint x      float spacingY   eventY - mStartDragPoint y      float newPositionLeft    dst left  lt  0   spacingX   spacingX   -1    dst left      float newPositionRight    spacingX    dst right      float newPositionTop    dst top  lt  0   spacingY   spacingY   -1    dst top      float newPositionBottom    spacingY    dst bottom      boolean x   true      boolean y   true       if  newPositionRight  lt  0 0f    newPositionLeft  gt  0 0f            if  newPositionRight  lt  0 0f  amp  amp  newPositionLeft  gt  0 0f                x   false            else               eventX   oldEventX              mStartDragPoint x   oldStartPointX                      if  newPositionBottom  lt  0 0f    newPositionTop  gt  0 0f            if  newPositionBottom  lt  0 0f  amp  amp  newPositionTop  gt  0 0f                y   false            else               eventY   oldEventY              mStartDragPoint y   oldStartPointY                       if  mDraggable            if  x  oldEventX   eventX          if  y  oldEventY   eventY          if  x  oldStartPointX   mStartDragPoint x          if  y  oldStartPointY   mStartDragPoint y            public void zoom MotionEvent event        float newDist   spacing event       boolean in   newDist  gt  oldDist       if   in  amp  amp  scale  lt   01f            return             scale   newDist   oldDist       int xChange    int    mBitmapWidth   scale    2       int yChange    int    mBitmapHeight   scale    2        if  xChange  gt  10  amp  amp  yChange  gt  10      ADDED THIS TO KEEP IT FROM GOING INVERSE      int xMidPoint     dst right - dst left    2    dst left      int yMidPoint     dst bottom - dst top    2    dst top       dst left    int   float   xMidPoint - xChange       dst top    int   float   yMidPoint - yChange        dst right    int   float   xMidPoint   xChange       dst bottom    int   float   yMidPoint   yChange               invalidate                Determine the space between the first two fingers     private float spacing MotionEvent event        float x   event getX 0  - event getX 1       float y   event getY 0  - event getY 1        return  float  Math sqrt x   x   y   y             Calculate the mid point of the first two fingers     private void midPoint PointF point  MotionEvent event        float x   event getX 0    event getX 1       float y   event getY 0    event getY 1       point set x   2  y   2        Override public boolean onLongClick View view          if  mode    DRAG            if   mStartPoint x  gt  dst left  amp  amp  mStartPoint x  lt  dst right   amp  amp   mStartPoint y  lt  dst bottom  amp  amp  mStartPoint y  gt  dst top                   amp  amp   mMovePoint x  gt  dst left  amp  amp  mMovePoint x  lt  dst right   amp  amp   mMovePoint y  lt  dst bottom  amp  amp  mMovePoint y  gt  dst top                 mode   MOVE              v vibrate 500                       return true      Override protected void onDraw Canvas canvas        super onDraw canvas       if  mode    MOVE            canvas drawBitmap mBitmap  src  dst  null           canvas drawBitmap mBitmap  src  dst  mPaint         else           canvas drawBitmap mBitmap  src  dst  null                   then add this to your activity  CustomZoomView customImageView    CustomZoomView  findViewById R id customZoomView   customImageView setBitmap yourBitmap        and this in your view in xml    lt your package name CustomZoomView    android id    id customZoomView     android layout width  fill parent     android layout height  fill parent     android longClickable  true   gt       and add this to your manifest   lt uses-permission android name  android permission VIBRATE   gt

User · Answer

This is yet another implementation based on the code posted by Nicolas Tyler   The following bugs are fixed    Setting minScale to a number less than 1 now works You don t need to use setImageBitmap   to set the image  you can use  for example setImageResource   All constructors now work properly   The following things  amongst others are tidied up    An OnTouchListener is not used  it s not necessary because the the class can just implement the onTouchEvent   method  The assignment right   width   saveScale - width -  2   redundantXSpace   saveScale   has been simplified to right    originalBitmapWidth   saveScale  - width Which  in my option  is much less confusing  Some member variables are removed  more state can probably be removed from this class    It s not perfect but here you go   import android content Context  import android graphics Matrix  import android graphics PointF  import android graphics drawable Drawable  import android util AttributeSet  import android view MotionEvent  import android view ScaleGestureDetector  import android widget ImageView          Created by alex on 23 02 16     Based on code posted by Nicolas Tyler here     https   stackoverflow com questions 6650398 android-imageview-zoom-in-and-zoom-out     public class ZoomableImageView extends ImageView        private class ScaleListener extends ScaleGestureDetector SimpleOnScaleGestureListener             Override         public boolean onScaleBegin ScaleGestureDetector detector                mode   ZOOM              return true                      Override         public boolean onScale ScaleGestureDetector detector                float scaleFactor   detector getScaleFactor                float newScale   saveScale   scaleFactor              if  newScale  lt  maxScale  amp  amp  newScale  gt  minScale                    saveScale   newScale                  float width   getWidth                    float height   getHeight                    right    originalBitmapWidth   saveScale  - width                  bottom    originalBitmapHeight   saveScale  - height                   float scaledBitmapWidth   originalBitmapWidth   saveScale                  float scaledBitmapHeight   originalBitmapHeight   saveScale                   if  scaledBitmapWidth  lt   width    scaledBitmapHeight  lt   height                        matrix postScale scaleFactor  scaleFactor  width   2  height   2                     else                       matrix postScale scaleFactor  scaleFactor  detector getFocusX    detector getFocusY                                                 return true                        static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      static final int CLICK   3       private int mode   NONE       private Matrix matrix   new Matrix         private PointF last   new PointF        private PointF start   new PointF        private float minScale   0 5f      private float maxScale   4f      private float   m       private float redundantXSpace  redundantYSpace      private float saveScale   1f      private float right  bottom  originalBitmapWidth  originalBitmapHeight       private ScaleGestureDetector mScaleDetector       public ZoomableImageView Context context            super context           init context              public ZoomableImageView Context context  AttributeSet attrs            super context  attrs           init context              public ZoomableImageView Context context  AttributeSet attrs  int defStyleAttr            super context  attrs  defStyleAttr           init context              private void init Context context            super setClickable true           mScaleDetector   new ScaleGestureDetector context  new ScaleListener             m   new float 9           setImageMatrix matrix           setScaleType ScaleType MATRIX               Override     protected void onMeasure int widthMeasureSpec  int heightMeasureSpec            super onMeasure widthMeasureSpec  heightMeasureSpec           int bmHeight   getBmHeight            int bmWidth   getBmWidth             float width   getMeasuredWidth            float height   getMeasuredHeight              Fit to screen          float scale   width  gt  height   height   bmHeight    width   bmWidth           matrix setScale scale  scale           saveScale   1f           originalBitmapWidth   scale   bmWidth          originalBitmapHeight   scale   bmHeight              Center the image         redundantYSpace    height - originalBitmapHeight           redundantXSpace    width - originalBitmapWidth            matrix postTranslate redundantXSpace   2  redundantYSpace   2            setImageMatrix matrix               Override     public boolean onTouchEvent MotionEvent event            mScaleDetector onTouchEvent event            matrix getValues m           float x   m Matrix MTRANS X           float y   m Matrix MTRANS Y           PointF curr   new PointF event getX    event getY              switch  event getAction                    when one finger is touching               set the mode to DRAG             case MotionEvent ACTION DOWN                  last set event getX    event getY                     start set last                   mode   DRAG                  break                when two fingers are touching               set the mode to ZOOM             case MotionEvent ACTION POINTER DOWN                  last set event getX    event getY                     start set last                   mode   ZOOM                  break                when a finger moves               If mode is applicable move image             case MotionEvent ACTION MOVE                    if the mode is ZOOM or                   if the mode is DRAG and already zoomed                 if  mode    ZOOM     mode    DRAG  amp  amp  saveScale  gt  minScale                         float deltaX   curr x - last x    x difference                     float deltaY   curr y - last y    y difference                     float scaleWidth   Math round originalBitmapWidth   saveScale     width after applying current scale                     float scaleHeight   Math round originalBitmapHeight   saveScale     height after applying current scale                      boolean limitX   false                      boolean limitY   false                         if scaleWidth is smaller than the views width                       in other words if the image width fits in the view                       limit left and right movement                     if  scaleWidth  lt  getWidth    amp  amp  scaleHeight  lt  getHeight                                 don t do anything                                           else if  scaleWidth  lt  getWidth                              deltaX   0                          limitY   true                                              if scaleHeight is smaller than the views height                       in other words if the image height fits in the view                       limit up and down movement                     else if  scaleHeight  lt  getHeight                              deltaY   0                          limitX   true                                              if the image doesnt fit in the width or height                       limit both up and down and left and right                     else                           limitX   true                          limitY   true                                             if  limitY                            if  y   deltaY  gt  0                                deltaY   -y                            else  if  y   deltaY  lt  -bottom                                deltaY   - y   bottom                                                                         if  limitX                            if  x   deltaX  gt  0                                deltaX   -x                            else if  x   deltaX  lt  -right                                deltaX   - x   right                                                                          move the image with the matrix                     matrix postTranslate deltaX  deltaY                         set the last touch location to the current                     last set curr x  curr y                                     break                first finger is lifted             case MotionEvent ACTION UP                  mode   NONE                  int xDiff    int  Math abs curr x - start x                   int yDiff    int  Math abs curr y - start y                   if  xDiff  lt  CLICK  amp  amp  yDiff  lt  CLICK                      performClick                    break                 second finger is lifted             case MotionEvent ACTION POINTER UP                  mode   NONE                  break                    setImageMatrix matrix           invalidate            return true             public void setMaxZoom float x            maxScale   x             private int getBmWidth             Drawable drawable   getDrawable            if  drawable    null                return drawable getIntrinsicWidth                      return 0             private int getBmHeight             Drawable drawable   getDrawable            if  drawable    null                return drawable getIntrinsicHeight                      return 0

User · Answer

I think Chirag Ravals  answer is great   The only thing it could be improved is moving all this code inside some class like    PinchZoomImageView extends ImageView        and adding there initial Image Matrix initialization to prevent zooming after the first tap    Override protected void onMeasure int widthMeasureSpec  int heightMeasureSpec        super onMeasure widthMeasureSpec  heightMeasureSpec       matrix   new Matrix this getImageMatrix         BTW  this will fix a bug mentioned by Muhammad Umar and Baz  P S  Having Max and Min zoom limits could be also useful  E g Max zoom is 2X and min zoom is the original scale when the image is fitted to screen   static final int MAX SCALE FACTOR   2    Override protected void onMeasure int widthMeasureSpec  int heightMeasureSpec        super onMeasure widthMeasureSpec  heightMeasureSpec           Getting initial Image matrix     mViewMatrix   new Matrix this getImageMatrix         mMinScaleMatrix   new Matrix mViewMatrix       float initialScale   getMatrixScale mViewMatrix         if  initialScale  lt  1 0f     Image is bigger than screen         mMaxScale   MAX SCALE FACTOR      else         mMaxScale   MAX SCALE FACTOR   initialScale       mMinScale   getMatrixScale mMinScaleMatrix        Override public boolean onTouch View v  MotionEvent event        ImageView view    ImageView  v         We set scale only after onMeasure was called and automatically fit image to screen     if  mWasScaleTypeSet            view setScaleType ImageView ScaleType MATRIX           mWasScaleTypeSet   true             float scale       dumpEvent event        switch  event getAction    amp  MotionEvent ACTION MASK        case MotionEvent ACTION DOWN     first finger down only         mCurSavedMatrix set mViewMatrix           start set event getX    event getY             mCurrentMode   DRAG          break       case MotionEvent ACTION UP     first finger lifted     case MotionEvent ACTION POINTER UP     second finger lifted         mCurrentMode   NONE           float resScale   getMatrixScale mViewMatrix            if  resScale  gt  mMaxScale                downscaleMatrix resScale  mViewMatrix             else if  resScale  lt  mMinScale              mViewMatrix   new Matrix mMinScaleMatrix           else if   resScale - mMinScale   lt  0 1f     Don t allow user to drag picture outside in case of FIT TO WINDOW zoom             mViewMatrix   new Matrix mMinScaleMatrix           else             break           break       case MotionEvent ACTION POINTER DOWN     first and second finger down         mOldDist   spacing event           Helper LOGD TAG   oldDist     mOldDist           if  mOldDist  gt  5f                mCurSavedMatrix set mViewMatrix               midPoint mCurMidPoint  event               mCurrentMode   ZOOM              Helper LOGD TAG   mode ZOOM                      break       case MotionEvent ACTION MOVE          if  mCurrentMode    DRAG                mViewMatrix set mCurSavedMatrix               mViewMatrix postTranslate event getX   - start x  event getY   - start y      create the transformation in the matrix  of points           else if  mCurrentMode    ZOOM                   pinch zooming             float newDist   spacing event               Helper LOGD TAG   newDist     newDist               if  newDist  gt  1 f                    mViewMatrix set mCurSavedMatrix                   scale   newDist   mOldDist     setting the scaling of the                                                matrix   if scale  gt  1 means                                                zoom in   if scale  lt  1 means                                                zoom out                 mViewMatrix postScale scale  scale  mCurMidPoint x  mCurMidPoint y                                   break             view setImageMatrix mViewMatrix      display the transformation on screen      return true     indicate event was handled                                                                                                                                                                                   PRIVATE SECTION                                                                                                                                                                                 These matrices will be used to scale points of the image private Matrix mViewMatrix   new Matrix    private Matrix mCurSavedMatrix   new Matrix       These PointF objects are used to record the point s  the user is touching private PointF start   new PointF    private PointF mCurMidPoint   new PointF    private float mOldDist   1f   private Matrix mMinScaleMatrix  private float mMinScale  private float mMaxScale  float   mTmpValues   new float 9   private boolean mWasScaleTypeSet           Returns scale factor of the Matrix     param matrix     return     private float getMatrixScale Matrix matrix        matrix getValues mTmpValues       return mTmpValues Matrix MSCALE X             Downscales matrix with the scale to maximum allowed scale factor  but the same translations     param scale     param dist     private void downscaleMatrix float scale  Matrix dist        float resScale   mMaxScale   scale      dist postScale resScale  resScale  mCurMidPoint x  mCurMidPoint y

User · Answer

It s old  but this may help someone else   Below TouchImageView class supports both zooming in out on either pinch or double tap  import android content Context  import android graphics Matrix  import android graphics PointF  import android graphics drawable Drawable  import android util AttributeSet  import android util Log  import android view GestureDetector  import android view MotionEvent  import android view ScaleGestureDetector  import android view View  import android widget ImageView   public class TouchImageView extends ImageView implements GestureDetector OnGestureListener  GestureDetector OnDoubleTapListener        Matrix matrix          We can be in one of these 3 states     static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      int mode   NONE          Remember some things for zooming     PointF last   new PointF        PointF start   new PointF        float minScale   1f      float maxScale   3f      float   m       int viewWidth  viewHeight      static final int CLICK   3      float saveScale   1f      protected float origWidth  origHeight      int oldMeasuredWidth  oldMeasuredHeight       ScaleGestureDetector mScaleDetector       Context context       public TouchImageView Context context            super context           sharedConstructing context              public TouchImageView Context context  AttributeSet attrs            super context  attrs           sharedConstructing context              GestureDetector mGestureDetector       private void sharedConstructing Context context            super setClickable true           this context   context          mGestureDetector   new GestureDetector context  this           mGestureDetector setOnDoubleTapListener this            mScaleDetector   new ScaleGestureDetector context  new ScaleListener             matrix   new Matrix            m   new float 9           setImageMatrix matrix           setScaleType ScaleType MATRIX            setOnTouchListener new OnTouchListener                   Override             public boolean onTouch View v  MotionEvent event                    mScaleDetector onTouchEvent event                   mGestureDetector onTouchEvent event                    PointF curr   new PointF event getX    event getY                      switch  event getAction                          case MotionEvent ACTION DOWN                          last set curr                           start set last                           mode   DRAG                          break                       case MotionEvent ACTION MOVE                          if  mode    DRAG                                float deltaX   curr x - last x                              float deltaY   curr y - last y                              float fixTransX   getFixDragTrans deltaX  viewWidth                                      origWidth   saveScale                               float fixTransY   getFixDragTrans deltaY  viewHeight                                      origHeight   saveScale                               matrix postTranslate fixTransX  fixTransY                               fixTrans                                last set curr x  curr y                                                     break                       case MotionEvent ACTION UP                          mode   NONE                          int xDiff    int  Math abs curr x - start x                           int yDiff    int  Math abs curr y - start y                           if  xDiff  lt  CLICK  amp  amp  yDiff  lt  CLICK                              performClick                            break                       case MotionEvent ACTION POINTER UP                          mode   NONE                          break                                     setImageMatrix matrix                   invalidate                    return true     indicate event was handled                                       public void setMaxZoom float x            maxScale   x              Override     public boolean onSingleTapConfirmed MotionEvent e            return false              Override     public boolean onDoubleTap MotionEvent e               Double tap is detected         Log i  MAIN TAG    Double tap detected            float origScale   saveScale          float mScaleFactor           if  saveScale    maxScale                saveScale   minScale              mScaleFactor   minScale   origScale            else               saveScale   maxScale              mScaleFactor   maxScale   origScale                     matrix postScale mScaleFactor  mScaleFactor  viewWidth   2                  viewHeight   2            fixTrans            return false              Override     public boolean onDoubleTapEvent MotionEvent e            return false              Override     public boolean onDown MotionEvent e            return false              Override     public void onShowPress MotionEvent e                 Override     public boolean onSingleTapUp MotionEvent e            return false              Override     public boolean onScroll MotionEvent e1  MotionEvent e2  float distanceX  float distanceY            return false              Override     public void onLongPress MotionEvent e                 Override     public boolean onFling MotionEvent e1  MotionEvent e2  float velocityX  float velocityY            return false             private class ScaleListener extends             ScaleGestureDetector SimpleOnScaleGestureListener            Override         public boolean onScaleBegin ScaleGestureDetector detector                mode   ZOOM              return true                      Override         public boolean onScale ScaleGestureDetector detector                float mScaleFactor   detector getScaleFactor                float origScale   saveScale              saveScale    mScaleFactor              if  saveScale  gt  maxScale                    saveScale   maxScale                  mScaleFactor   maxScale   origScale                else if  saveScale  lt  minScale                    saveScale   minScale                  mScaleFactor   minScale   origScale                             if  origWidth   saveScale  lt   viewWidth                        origHeight   saveScale  lt   viewHeight                  matrix postScale mScaleFactor  mScaleFactor  viewWidth   2                          viewHeight   2               else                 matrix postScale mScaleFactor  mScaleFactor                          detector getFocusX    detector getFocusY                  fixTrans                return true                       void fixTrans             matrix getValues m           float transX   m Matrix MTRANS X           float transY   m Matrix MTRANS Y            float fixTransX   getFixTrans transX  viewWidth  origWidth   saveScale           float fixTransY   getFixTrans transY  viewHeight  origHeight                   saveScale            if  fixTransX    0    fixTransY    0              matrix postTranslate fixTransX  fixTransY              float getFixTrans float trans  float viewSize  float contentSize            float minTrans  maxTrans           if  contentSize  lt   viewSize                minTrans   0              maxTrans   viewSize - contentSize            else               minTrans   viewSize - contentSize              maxTrans   0                     if  trans  lt  minTrans              return -trans   minTrans          if  trans  gt  maxTrans              return -trans   maxTrans          return 0             float getFixDragTrans float delta  float viewSize  float contentSize            if  contentSize  lt   viewSize                return 0                    return delta              Override     protected void onMeasure int widthMeasureSpec  int heightMeasureSpec            super onMeasure widthMeasureSpec  heightMeasureSpec           viewWidth   MeasureSpec getSize widthMeasureSpec           viewHeight   MeasureSpec getSize heightMeasureSpec                          Rescales image on rotation                    if  oldMeasuredHeight    viewWidth  amp  amp  oldMeasuredHeight    viewHeight                    viewWidth    0    viewHeight    0              return          oldMeasuredHeight   viewHeight          oldMeasuredWidth   viewWidth           if  saveScale    1                   Fit to screen              float scale               Drawable drawable   getDrawable                if  drawable    null    drawable getIntrinsicWidth      0                        drawable getIntrinsicHeight      0                  return              int bmWidth   drawable getIntrinsicWidth                int bmHeight   drawable getIntrinsicHeight                 Log d  bmSize    bmWidth      bmWidth     bmHeight       bmHeight                float scaleX    float  viewWidth    float  bmWidth              float scaleY    float  viewHeight    float  bmHeight              scale   Math min scaleX  scaleY               matrix setScale scale  scale                   Center the image             float redundantYSpace    float  viewHeight                     -  scale    float  bmHeight               float redundantXSpace    float  viewWidth                     -  scale    float  bmWidth               redundantYSpace     float  2              redundantXSpace     float  2               matrix postTranslate redundantXSpace  redundantYSpace                origWidth   viewWidth - 2   redundantXSpace              origHeight   viewHeight - 2   redundantYSpace              setImageMatrix matrix                     fixTrans              Usage  You can replace your ImageView with TouchImageView in both XML  amp  java  1  For XML   lt  xml version  1 0  encoding  utf-8   gt   lt com example android myapp TouchImageView      xmlns android  http   schemas android com apk res android      android id    id imViewedImage      android layout width  match parent      android layout height  match parent      android clickable  true      android focusable  true    gt    2  For Java  TouchImageView imViewedImage   findViewById R id imViewedImage

User · Answer

I know it is a bit late for this answer  but I hope it helps someone   I was looking for the same thing  Zoom using pinch  and dragging image  and I found this Android Developers Blog link   Works perfect  No artifacts or what so ever  It uses ScaleGestureDetector

User · Answer

I am Using this one it is working perfectly    lt your packagename MyZoomableImageViewTouch         android id    id mediaImage          android layout width  fill parent          android layout height  fill parent          android scaleType  matrix   gt    My a MyZoomableImageViewTouch class is below   public class MyZoomableImageViewTouch extends ImageViewTouch        static final float SCROLL DELTA THRESHOLD   1 0f       public MyZoomableImageViewTouch Context context  AttributeSet attrs  int defStyle                super context  attrs  defStyle           init               public MyZoomableImageViewTouch Context context  AttributeSet attrs            super context  attrs           init               public MyZoomableImageViewTouch Context context                super context           init               private void init             View OnTouchListener listener   new View OnTouchListener                  Override             public boolean onTouch View v  MotionEvent event                    if  getScale    gt  1f                        getParent   requestDisallowInterceptTouchEvent true                     else                       getParent   requestDisallowInterceptTouchEvent false                                     return false                                   setOnTouchListener listener           setDisplayType DisplayType FIT TO SCREEN               Override     protected float onDoubleTapPost float scale  float maxZoom            if  scale    1f                mDoubleTapDirection   1              return 1f                    if  mDoubleTapDirection    1                mDoubleTapDirection   -1              if   scale    mScaleFactor   2    lt   maxZoom                    return scale   mScaleFactor                else                   mDoubleTapDirection   -1                  return maxZoom                          else               mDoubleTapDirection   1              return 1f                        Override     public boolean canScroll int direction            RectF bitmapRect   getBitmapRect            updateRect bitmapRect  mScrollRect           Rect imageViewRect   new Rect            getGlobalVisibleRect imageViewRect            if  null    bitmapRect                return false                     if  Math abs bitmapRect right - imageViewRect right   lt  SCROLL DELTA THRESHOLD                if  direction  lt  0                    return false                                   if  Math abs bitmapRect left - mScrollRect left   lt  SCROLL DELTA THRESHOLD                if  direction  gt  0                    return false                                  return true              Override     public boolean onScroll MotionEvent e1  MotionEvent e2  float distanceX  float distanceY                if  getScale      1f  return false          if  distanceX    0  amp  amp   canScroll  int  -distanceX                 getParent   requestDisallowInterceptTouchEvent false               return false            else               getParent   requestDisallowInterceptTouchEvent true               mUserScaled   true              scrollBy -distanceX  -distanceY               invalidate                return true

User · Answer

I think why you want to zoom-in and zoom-out the image view is because your image view is small and zooming in the image there will not let the image come out of the image view  Instead  image starts disappearing from the boundaries while zooming in  So letting the image come out of the image while we zoom in is what you want I guess   So there are two tricks  according to me  to achieve this-    Change the layout params of the image view to cover the whole outermost view or view group at runtime while we are about to zoom-in the image  Make an expanded Image view or Full Image View  height and width   Outermost View or View Group  in xml file and set it s visibility to gone  When we are about to zoom-in the image  load the image from small Image View into full Img View  map the image in fullImgView to image in smallImgView and make it s view visible    Trick no 1 does not work when the image View is nested very much inside other views  like in nested recycler view   Trick no 2 works always  -   Here is the implementation of trick no 2 -   public class ZoomOnTouchListener extends AppCompatActivity implements View OnTouchListener        private Matrix matrix   new Matrix         private boolean isfullImgViewActive   false         above boolean gets true when when we firstly move 2 fingers on the smallImgView and in this case smallImgView gets invisible and fullImgView gets visible        and false if smallImgView is visible and fullImgView is gone      private float   matrixArray   new float 9       private float orgScale       private PointF start   new PointF        private PointF prevP1   new PointF        private PointF prevP2   new PointF        private PointF mid   new PointF        private float oldDist   1f       private ImageView mfullImgView      private ImageView smallImgView        Override     protected void onCreate  Nullable Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main            mfullImgView    ImageView findViewById R id imgView2           mfullImgView setVisibility View GONE           smallImgView    ImageView findViewById R id imgView           smallImgView setOnTouchListener this                    Override     public boolean onTouch View v  MotionEvent event              Log i  0    OnTouch              if v instanceof ImageView                ImageView imgView    ImageView  v               boolean isImgViewSmall    imgView    smallImgView                switch  event getAction    amp  MotionEvent ACTION MASK                     case MotionEvent ACTION DOWN       first finger down only                        Log i  T    Motion Event  ACTION DOWN                         if isImgViewSmall                          start set event getX    event getY                          prevP1 set event getX    event getY                          return true                   case MotionEvent ACTION POINTER DOWN    second finger and other fingers down                      prevP1 set event getX 0   event getY 0                        prevP2 set event getX 1   event getY 1                         oldDist   spacing event                        midPoint mid  event                        break                   case MotionEvent ACTION MOVE      it doesn t mean fingers are moved  In this case  all pointers which are active are batched together                                                    this case occurs after action down or action pointer down                        Log i  Tag   event getX       event getY                         if event getPointerCount      2                             PointF newMid   new PointF                            midPoint newMid event                            float newDist   spacing event                            float scale   newDist oldDist                           if   isfullImgViewActive        is smallImgView is visible and mfullImgView is gone                             Log i  tag    true                                 isfullImgViewActive   true                               matrix set imgView getImageMatrix         note - do not write matrix   imgView getImageMatrix   because it gives the smallImgView s matrix reference to the matrix variable and changes on matrix will reflect on smallImgView                             matrix getValues matrixArray                                orgScale   matrixArray 0                                smallImgView setVisibility View INVISIBLE                                mfullImgView setImageDrawable smallImgView getDrawable                                 mfullImgView setScaleType ImageView ScaleType MATRIX                                mfullImgView setVisibility View VISIBLE                                  To map the image of mFullImgView to that of smallImgView we have to                                 translate the mFullImgView s image                             matrix postTranslate tx  ty                                            NOTE                                              here  tx ty  are coordinates of top-left corner of smallimgView and                                 they MUST be relative to the origin of Outermost view or view group                                 where fullImgView is placed  So find tx ty in your case by yourself                              mfullImgView setImageMatrix matrix                                                            if isImgViewSmall                                matrix postScale scale  scale  mid x   tx  mid y   ty                                                     else                              matrix postScale scale  scale  mid x  mid y                                                     oldDist   newDist                           matrix postTranslate newMid x - mid x  newMid y - mid y                            matrix getValues matrixArray                            mid set newMid                             prevP1 set event getX 0   event getY 0                            prevP2 set event getX 1   event getY 1                                                else if event getPointerCount      1                             if isfullImgViewActive                                 matrix postTranslate event getX   - prevP1 x  event getY   - prevP1 y                               matrix getValues matrixArray                                                      prevP1 set event getX 0   event getY 0                                                break                   case MotionEvent ACTION POINTER UP     second finger lifted                        Now if pointer of index 0 is lifted then pointer of index 1 will get index 0                      if event getActionIndex      0  amp  amp  isfullImgViewActive                           Log i  TAg   event getActionIndex                                prevP1 set prevP2                                              break                   case MotionEvent ACTION UP     first finger lifted or all fingers are lifted                      if isImgViewSmall  amp  amp   isfullImgViewActive                             imgView setScaleType ImageView ScaleType FIT CENTER                            int xDiff    int  Math abs event getX   - start x                           int yDiff    int  Math abs event getY   - start y                           if  xDiff    0  amp  amp  yDiff    0                                imgView performClick                                return true                                                                       if isfullImgViewActive                           if matrixArray 0   lt   orgScale      matrixArray 0  is Scale X value                              mfullImgView setOnTouchListener null                               mfullImgView setImageDrawable null                               mfullImgView setVisibility View GONE                                smallImgView setOnTouchListener this                               smallImgView setScaleType ImageView ScaleType FIT CENTER                               smallImgView setVisibility View VISIBLE                                isfullImgViewActive   false                                                     else if matrixArray 0   gt  orgScale  amp  amp  isImgViewSmall      if the imgView was smallImgView                              smallImgView setOnTouchListener null                               smallImgView setScaleType ImageView ScaleType FIT CENTER                               smallImgView setVisibility View GONE       or View INVISIBLE                              mfullImgView setOnTouchListener this                                                                        return true                                end of Switch statement               if isfullImgViewActive        active means visible                 mfullImgView setImageMatrix matrix      display the transformation on screen                            return true     indicate event was handled                   else             return false              private float spacing MotionEvent event                float x   event getX 0  - event getX 1           float y   event getY 0  - event getY 1           return  float  Math sqrt x   x   y   y               private void midPoint PointF point  MotionEvent event                float x   event getX 0    event getX 1           float y   event getY 0    event getY 1           point set x   2  y   2              NOTE - Don t set OnClickListener to mfullImgView before setting onTouchListener to it  Setting that will let the fullImageView if it is visible  steal the touch event of putting second finger down after lifting it for the first time because we want to let the smallImgView take all the touch events until all the fingers are lifted up for the first time

User · Answer

I have improved the answer I got from stack for flawless ZOOM  two finger    ROTATION  two finger    DRAG  Single finger                                    XML code                     lt  xml version  1 0  encoding  utf-8   gt   lt LinearLayout     xmlns android  http   schemas android com apk res android      xmlns app  http   schemas android com apk res-auto      xmlns tools  http   schemas android com tools      android layout width  match parent      android layout height  match parent      tools context  com example flochat imageviewzoomforstack MainActivity  gt        lt ImageView         android id    id imageview trash          android layout width  wrap content          android layout height  wrap content          android src   drawable trash    gt    lt  LinearLayout gt                                  Java code                            public class MainActivity extends AppCompatActivity        ImageView photoview2      float   lastEvent   null      float d   0f      float newRot   0f      private boolean isZoomAndRotate      private boolean isOutSide      private static final int NONE   0      private static final int DRAG   1      private static final int ZOOM   2      private int mode   NONE      private PointF start   new PointF        private PointF mid   new PointF        float oldDist   1f      private float xCoOrdinate  yCoOrdinate        Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           requestWindowFeature Window FEATURE NO TITLE           getWindow   setFlags WindowManager LayoutParams FLAG FULLSCREEN                  WindowManager LayoutParams FLAG FULLSCREEN            setContentView R layout activity main            photoview2   findViewById R id imageview trash            photoview2 setOnTouchListener new View OnTouchListener                  Override             public boolean onTouch View v  MotionEvent event                    ImageView view    ImageView  v                  view bringToFront                    viewTransformation view  event                   return true                                        private void viewTransformation View view  MotionEvent event            switch  event getAction    amp  MotionEvent ACTION MASK                case MotionEvent ACTION DOWN              xCoOrdinate   view getX   - event getRawX                yCoOrdinate   view getY   - event getRawY                     start set event getX    event getY                     isOutSide   false                  mode   DRAG                  lastEvent   null                  break              case MotionEvent ACTION POINTER DOWN                  oldDist   spacing event                   if  oldDist  gt  10f                        midPoint mid  event                       mode   ZOOM                                     lastEvent   new float 4                   lastEvent 0    event getX 0                   lastEvent 1    event getX 1                   lastEvent 2    event getY 0                   lastEvent 3    event getY 1                   d   rotation event                   break              case MotionEvent ACTION UP                  isZoomAndRotate   false                  if  mode    DRAG                        float x   event getX                        float y   event getY                                  case MotionEvent ACTION OUTSIDE                  isOutSide   true                  mode   NONE                  lastEvent   null              case MotionEvent ACTION POINTER UP                  mode   NONE                  lastEvent   null                  break              case MotionEvent ACTION MOVE                  if   isOutSide                        if  mode    DRAG                            isZoomAndRotate   false                          view animate   x event getRawX     xCoOrdinate  y event getRawY     yCoOrdinate  setDuration 0  start                                              if  mode    ZOOM  amp  amp  event getPointerCount      2                            float newDist1   spacing event                           if  newDist1  gt  10f                                float scale   newDist1   oldDist   view getScaleX                                view setScaleX scale                               view setScaleY scale                                                     if  lastEvent    null                                newRot   rotation event                               view setRotation  float   view getRotation      newRot - d                                                                                       break                       private float rotation MotionEvent event            double delta x    event getX 0  - event getX 1            double delta y    event getY 0  - event getY 1            double radians   Math atan2 delta y  delta x           return  float  Math toDegrees radians              private float spacing MotionEvent event            float x   event getX 0  - event getX 1           float y   event getY 0  - event getY 1           return  int  Math sqrt x   x   y   y              private void midPoint PointF point  MotionEvent event            float x   event getX 0    event getX 1           float y   event getY 0    event getY 1           point set x   2  y   2                                        Just pass any view which you want to zoom rotate drag to viewTransformation   method  Very applicable for textview zoom  It will not pixelate text

User · Answer

I made my own custom imageview with pinch to zoom  There is no limits borders on Chirag Ravals code  so user can drag the image off the screen     Here is the CustomImageView class       public class CustomImageVIew extends ImageView implements OnTouchListener         private Matrix matrix   new Matrix        private Matrix savedMatrix   new Matrix         static final int NONE   0      static final int DRAG   1      static final int ZOOM   2       private int mode   NONE       private PointF mStartPoint   new PointF        private PointF mMiddlePoint   new PointF        private Point mBitmapMiddlePoint   new Point         private float oldDist   1f      private float matrixValues      0f  0f  0f  0f  0f  0f  0f  0f  0f       private float scale      private float oldEventX   0      private float oldEventY   0      private float oldStartPointX   0      private float oldStartPointY   0      private int mViewWidth   -1      private int mViewHeight   -1      private int mBitmapWidth   -1      private int mBitmapHeight   -1      private boolean mDraggable   false        public CustomImageVIew Context context            this context  null  0              public CustomImageVIew Context context  AttributeSet attrs            this context  attrs  0              public CustomImageVIew Context context  AttributeSet attrs  int defStyle            super context  attrs  defStyle           this setOnTouchListener this               Override     public void onSizeChanged  int w  int h  int oldw  int oldh           super onSizeChanged w  h  oldw  oldh           mViewWidth   w          mViewHeight   h             public void setBitmap Bitmap bitmap           if bitmap    null               setImageBitmap bitmap                mBitmapWidth   bitmap getWidth                mBitmapHeight   bitmap getHeight                mBitmapMiddlePoint x    mViewWidth   2  -  mBitmapWidth    2               mBitmapMiddlePoint y    mViewHeight   2  -  mBitmapHeight   2                matrix postTranslate mBitmapMiddlePoint x  mBitmapMiddlePoint y               this setImageMatrix matrix                         Override     public boolean onTouch View v  MotionEvent event           switch  event getAction    amp  MotionEvent ACTION MASK            case MotionEvent ACTION DOWN              savedMatrix set matrix               mStartPoint set event getX    event getY                 mode   DRAG              break          case MotionEvent ACTION POINTER DOWN              oldDist   spacing event               if oldDist  gt  10f                   savedMatrix set matrix                   midPoint mMiddlePoint  event                   mode   ZOOM                            break          case MotionEvent ACTION UP          case MotionEvent ACTION POINTER UP              mode   NONE              break          case MotionEvent ACTION MOVE              if mode    DRAG                   drag event                 else if mode    ZOOM                   zoom event                              break                     return true              public void drag MotionEvent event          matrix getValues matrixValues           float left   matrixValues 2          float top   matrixValues 5          float bottom    top    matrixValues 0    mBitmapHeight   - mViewHeight         float right    left    matrixValues 0    mBitmapWidth   -mViewWidth          float eventX   event getX           float eventY   event getY           float spacingX   eventX - mStartPoint x         float spacingY   eventY - mStartPoint y         float newPositionLeft    left   lt  0   spacingX   spacingX   -1    left         float newPositionRight    spacingX    right         float newPositionTop    top   lt  0   spacingY   spacingY   -1    top         float newPositionBottom    spacingY    bottom         boolean x   true         boolean y   true          if newPositionRight  lt  0 0f    newPositionLeft  gt  0 0f              if newPositionRight  lt  0 0f  amp  amp  newPositionLeft  gt  0 0f                  x   false               else                 eventX   oldEventX                 mStartPoint x   oldStartPointX                               if newPositionBottom  lt  0 0f    newPositionTop  gt  0 0f              if newPositionBottom  lt  0 0f  amp  amp  newPositionTop  gt  0 0f                  y   false               else                 eventY   oldEventY                 mStartPoint y   oldStartPointY                                if mDraggable              matrix set savedMatrix              matrix postTranslate x  eventX - mStartPoint x   0  y  eventY - mStartPoint y   0              this setImageMatrix matrix              if x oldEventX   eventX             if y oldEventY   eventY             if x oldStartPointX   mStartPoint x             if y oldStartPointY   mStartPoint y                     public void zoom MotionEvent event          matrix getValues matrixValues           float newDist   spacing event          float bitmapWidth   matrixValues 0    mBitmapWidth         float bimtapHeight   matrixValues 0    mBitmapHeight         boolean in   newDist  gt  oldDist          if  in  amp  amp  matrixValues 0   lt  1              return                  if bitmapWidth  gt  mViewWidth    bimtapHeight  gt  mViewHeight              mDraggable   true           else             mDraggable   false                   float midX    mViewWidth   2          float midY    mViewHeight   2           matrix set savedMatrix          scale   newDist   oldDist         matrix postScale scale  scale  bitmapWidth  gt  mViewWidth   mMiddlePoint x   midX  bimtapHeight  gt  mViewHeight   mMiddlePoint y   midY            this setImageMatrix matrix                       Determine the space between the first two fingers        private float spacing MotionEvent event            float x   event getX 0  - event getX 1           float y   event getY 0  - event getY 1            return  float Math sqrt x   x   y   y                  Calculate the mid point of the first two fingers        private void midPoint PointF point  MotionEvent event            float x   event getX 0    event getX 1           float y   event getY 0    event getY 1           point set x   2  y   2               This is how you can use it in your activity   CustomImageVIew mImageView    CustomImageVIew findViewById R id customImageVIew1   mImage setBitmap your bitmap     And layout    lt your package name CustomImageVIew         android id    id customImageVIew1          android layout width  fill parent          android layout height  fill parent          android layout marginBottom  15dp          android layout marginLeft  15dp          android layout marginRight  15dp          android layout marginTop  15dp          android layout centerHorizontal  true          android layout centerVertical  true           android scaleType  matrix   gt     important

User · Answer

ZoomLib Link  https   drive google com uc export download amp id 0B34PUThnUsjVaHpkaGk0Z1hSRU0       Override protected void onCreate Bundle savedInstanceState    super onCreate savedInstanceState   setContentView R layout dummy layout for zooming     Activity layout  mZoomLinearLayout    LinearLayout  findViewById R id mZoomLinearLayout     LinearLayout inside Activity layout View v     LayoutInflater  getSystemService Context LAYOUT INFLATER SERVICE   inflate R layout layout for zoom  null  false     View wants to zoom v setLayoutParams new LinearLayout LayoutParams LinearLayout LayoutParams FILL PARENT  LinearLayout LayoutParams FILL PARENT    ZoomView zoomView   new ZoomView this     intialize lib zoomView addView v   mZoomLinearLayout addView zoomView

User · Answer

The other implementations here all have some kind of a flaw  so i basically mixed them up and came up with this   Create a custom view like this   ZoomableImageView java   import android content Context  import android graphics Bitmap  import android graphics Matrix  import android graphics PointF  import android util AttributeSet  import android view MotionEvent  import android view ScaleGestureDetector  import android view View  import android widget ImageView   public class ZoomableImageView extends ImageView       Matrix matrix   new Matrix         static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      static final int CLICK   3      int mode   NONE       PointF last   new PointF        PointF start   new PointF        float minScale   1f      float maxScale   4f      float   m       float redundantXSpace  redundantYSpace      float width  height      float saveScale   1f      float right  bottom  origWidth  origHeight  bmWidth  bmHeight       ScaleGestureDetector mScaleDetector      Context context       public ZoomableImageView Context context  AttributeSet attr                super context  attr           super setClickable true           this context   context          mScaleDetector   new ScaleGestureDetector context  new ScaleListener             matrix setTranslate 1f  1f           m   new float 9           setImageMatrix matrix           setScaleType ScaleType MATRIX            setOnTouchListener new OnTouchListener                           Override             public boolean onTouch View v  MotionEvent event                                mScaleDetector onTouchEvent event                    matrix getValues m                   float x   m Matrix MTRANS X                   float y   m Matrix MTRANS Y                   PointF curr   new PointF event getX    event getY                      switch  event getAction                                            when one finger is touching                       set the mode to DRAG                     case MotionEvent ACTION DOWN                          last set event getX    event getY                             start set last                           mode   DRAG                          break                        when two fingers are touching                       set the mode to ZOOM                     case MotionEvent ACTION POINTER DOWN                          last set event getX    event getY                             start set last                           mode   ZOOM                          break                        when a finger moves                       If mode is applicable move image                     case MotionEvent ACTION MOVE                            if the mode is ZOOM or                           if the mode is DRAG and already zoomed                         if  mode    ZOOM     mode    DRAG  amp  amp  saveScale  gt  minScale                                                         float deltaX   curr x - last x    x difference                             float deltaY   curr y - last y    y difference                             float scaleWidth   Math round origWidth   saveScale     width after applying current scale                             float scaleHeight   Math round origHeight   saveScale     height after applying current scale                               if scaleWidth is smaller than the views width                               in other words if the image width fits in the view                               limit left and right movement                             if  scaleWidth  lt  width                                                                deltaX   0                                  if  y   deltaY  gt  0                                      deltaY   -y                                  else if  y   deltaY  lt  -bottom                                      deltaY   - y   bottom                                                               if scaleHeight is smaller than the views height                               in other words if the image height fits in the view                               limit up and down movement                             else if  scaleHeight  lt  height                                                                deltaY   0                                  if  x   deltaX  gt  0                                      deltaX   -x                                  else if  x   deltaX  lt  -right                                      deltaX   - x   right                                                               if the image doesnt fit in the width or height                               limit both up and down and left and right                             else                                                               if  x   deltaX  gt  0                                      deltaX   -x                                  else if  x   deltaX  lt  -right                                      deltaX   - x   right                                    if  y   deltaY  gt  0                                      deltaY   -y                                  else if  y   deltaY  lt  -bottom                                      deltaY   - y   bottom                                                               move the image with the matrix                             matrix postTranslate deltaX  deltaY                                 set the last touch location to the current                             last set curr x  curr y                                                     break                        first finger is lifted                     case MotionEvent ACTION UP                          mode   NONE                          int xDiff    int  Math abs curr x - start x                           int yDiff    int  Math abs curr y - start y                           if  xDiff  lt  CLICK  amp  amp  yDiff  lt  CLICK                              performClick                            break                         second finger is lifted                     case MotionEvent ACTION POINTER UP                          mode   NONE                          break                                    setImageMatrix matrix                   invalidate                    return true                                         Override     public void setImageBitmap Bitmap bm                super setImageBitmap bm           bmWidth   bm getWidth            bmHeight   bm getHeight               public void setMaxZoom float x                maxScale   x             private class ScaleListener extends ScaleGestureDetector SimpleOnScaleGestureListener                 Override         public boolean onScaleBegin ScaleGestureDetector detector                        mode   ZOOM              return true                      Override         public boolean onScale ScaleGestureDetector detector                        float mScaleFactor   detector getScaleFactor                float origScale   saveScale              saveScale    mScaleFactor              if  saveScale  gt  maxScale                                saveScale   maxScale                  mScaleFactor   maxScale   origScale                            else if  saveScale  lt  minScale                                saveScale   minScale                  mScaleFactor   minScale   origScale                            right   width   saveScale - width -  2   redundantXSpace   saveScale               bottom   height   saveScale - height -  2   redundantYSpace   saveScale               if  origWidth   saveScale  lt   width    origHeight   saveScale  lt   height                                matrix postScale mScaleFactor  mScaleFactor  width   2  height   2                   if  mScaleFactor  lt  1                                        matrix getValues m                       float x   m Matrix MTRANS X                       float y   m Matrix MTRANS Y                       if  mScaleFactor  lt  1                                                if  Math round origWidth   saveScale   lt  width                                                        if  y  lt  -bottom                                  matrix postTranslate 0  - y   bottom                                else if  y  gt  0                                  matrix postTranslate 0  -y                                                     else                                                       if  x  lt  -right                                  matrix postTranslate - x   right   0                               else if  x  gt  0                                  matrix postTranslate -x  0                                                                                               else                               matrix postScale mScaleFactor  mScaleFactor  detector getFocusX    detector getFocusY                     matrix getValues m                   float x   m Matrix MTRANS X                   float y   m Matrix MTRANS Y                   if  mScaleFactor  lt  1                        if  x  lt  -right                          matrix postTranslate - x   right   0                       else if  x  gt  0                          matrix postTranslate -x  0                       if  y  lt  -bottom                          matrix postTranslate 0  - y   bottom                        else if  y  gt  0                          matrix postTranslate 0  -y                                               return true                        Override     protected void onMeasure  int widthMeasureSpec  int heightMeasureSpec                super onMeasure widthMeasureSpec  heightMeasureSpec           width   MeasureSpec getSize widthMeasureSpec           height   MeasureSpec getSize heightMeasureSpec             Fit to screen          float scale          float scaleX    width   bmWidth          float scaleY   height   bmHeight          scale   Math min scaleX  scaleY           matrix setScale scale  scale           setImageMatrix matrix           saveScale   1f              Center the image         redundantYSpace   height -  scale   bmHeight            redundantXSpace   width -  scale   bmWidth           redundantYSpace    2          redundantXSpace    2           matrix postTranslate redundantXSpace  redundantYSpace            origWidth   width - 2   redundantXSpace          origHeight   height - 2   redundantYSpace          right   width   saveScale - width -  2   redundantXSpace   saveScale           bottom   height   saveScale - height -  2   redundantYSpace   saveScale           setImageMatrix matrix             Then add the image like this   ZoomableImageView touch    ZoomableImageView findViewById R id IMAGEID   touch setImageBitmap bitmap     Add the view like this in XML    lt PACKAGE ZoomableImageView android id    id IMAGEID  android layout width  match parent  android layout height  match parent   gt

User · Answer

I got the most helpful answer from  Nicolas Tyler but I had issues with how the syntax and logic worked  I also did not want any Alpha space and my Algebra was rusty  After 3 days I have put together my own version of this   My answer differs from  Nicolas Tyler with the following    Different variable names which I found made more sense in underlying contextual uses This Pinch-Zoom image class does NOT show alpha space and will let you zoom in and out and still not let you over under pan an image and reveal alpha space Added deep comments to the matrix section to explain what was going on with the math involved This image class will also let you pass in a resourceId and it will create a bitmap from it Much simpler algorithms for both scaling and translation and few variables Changing the image within this will cause it to zoom in out such that the new image takes up the view container   A great resource refresher on Algebra can be found here  https   youtu be IiXB6tYtY4w t 4m12s That video covers the core of Scalar and Translation matrixes  and will help you make sense of the MTRANS X and MTRANS Y stuff   If you have questions ask and I will do my best to answer  but I am NO Algebra expert    import android content Context  import android graphics Bitmap  import android graphics BitmapFactory  import android graphics Matrix  import android graphics PointF  import android view MotionEvent  import android view ScaleGestureDetector  import android view View  import android widget ImageView   public class iImage extends ImageView       static final int NONE MODE   0      static final int DRAG MODE   1      static final int ZOOM MODE   2      int  mode   NONE MODE       Matrix  matrix   new Matrix        PointF  previousPoint   new PointF        PointF  startPoint   new PointF        float  currentScale   1f      float  minScale   1f      float  maxScale   3f      float    arrayOf9Floats      float  bitmapWidth   bitmapHeight  displayWidth   displayHeight      ScaleGestureDetector  scaleDetector      Context  context       public iImage Context context                super context           super setClickable true            context   context           scaleDetector   new ScaleGestureDetector context  new ScaleListener              arrayOf9Floats   new float 9           setScaleType ScaleType MATRIX           setOnTouchListener new OnTouchListener                  Override             public boolean onTouch View v  MotionEvent event                    return handleTouch v  event                                        private boolean handleTouch View v  MotionEvent event                 scaleDetector onTouchEvent event             Contrary to how this line looks  the matrix is not setting the values from the arrayOf9Floats  but rather taking the           matrix values and assigning them into the arrayOf9Floats  I extremely dislike this syntax and I think           it should have been written as  arrayOf9Floats    matrix getValues   but that s Android for you             matrix getValues  arrayOf9Floats              Look at https   youtu be IiXB6tYtY4w t 4m12s   it shows scale  rotate  and translate matrices           If you look at the translate matrix  you ll see that the 3rd and 6th values are the values which represent x and y translations respectively           this corresponds to the 2nd and 5th values in the array and hence why the MTRANS X and MTRANS Y have the constants 2 and 5 respectively         float xTranslate    arrayOf9Floats Matrix MTRANS X           float yTranslate    arrayOf9Floats Matrix MTRANS Y           PointF currentEventPoint   new PointF event getX    event getY             switch  event getAction                            First finger down only             case MotionEvent ACTION DOWN                   previousPoint set event getX    event getY                      startPoint set  previousPoint                    mode   DRAG MODE                  break                Second finger down             case MotionEvent ACTION POINTER DOWN                   previousPoint set event getX    event getY                      startPoint set  previousPoint                    mode   ZOOM MODE                  break              case MotionEvent ACTION MOVE                  if   mode    ZOOM MODE     mode    DRAG MODE                                         float deltaX   currentEventPoint x -  previousPoint x                      float deltaY   currentEventPoint y -  previousPoint y                        In matrix terms  going right is   and going left is                         Moving the image right past 0 means it will show alpha space on the left so we dont want that                       Keep in mind this is a TOP LEFT pivot point  so we dont want the top left to be past 0 lest we have alpha space                     if xTranslate   deltaX  gt  0                                                  get absolute of how much into the negative we would have gone                         float excessDeltaX   Math abs xTranslate   deltaX                             take that excess away from deltaX so X wont got less than 0 after the translation                         deltaX   deltaX - excessDeltaX                                               Going left we dont want the negative value to be less than the negative width of the sprite  lest we get alpha space on the right                       The width is going to be the width of the bitmap   scale and we want the - of it because we are checking for left movement                       We also need to account for the width of the DISPLAY CONTAINER  i e   displayWidth  so that gets subtracted                       i e  we want the max scroll width value                     float maxScrollableWidth    bitmapWidth    currentScale -  displayWidth                      if xTranslate   deltaX  lt  -maxScrollableWidth                                                  this forces the max possible translate to always match the - of maxScrollableWidth                         deltaX   -maxScrollableWidth - xTranslate                                               repeat for Y                     if yTranslate   deltaY  gt  0                                                float excessDeltaY   Math abs yTranslate   deltaY                           deltaY   deltaY - excessDeltaY                                             float maxScrollableHeight    bitmapHeight    currentScale -  displayWidth                      if yTranslate   deltaY  lt  -maxScrollableHeight                                                  this forces the max possible translate to always match the - of maxScrollableWidth                         deltaY   -maxScrollableHeight - yTranslate                                              matrix postTranslate deltaX  deltaY                        matrix getValues  arrayOf9Floats                         System out println  matrix                         previousPoint set currentEventPoint x  currentEventPoint y                                     break              case MotionEvent ACTION POINTER UP                   mode   NONE MODE                  break                    setImageMatrix  matrix           invalidate            return true              Override     public void setImageBitmap Bitmap bm                super setImageBitmap bm            bitmapWidth   bm getWidth             bitmapHeight   bm getHeight            invalidate                Override     public void setImageResource int resid                Bitmap bitmapImage   BitmapFactory decodeResource  context getResources    resid           setImageBitmap bitmapImage              private class ScaleListener extends ScaleGestureDetector SimpleOnScaleGestureListener                 Override         public boolean onScaleBegin ScaleGestureDetector detector                         mode   ZOOM MODE              return true                      Override         public boolean onScale ScaleGestureDetector detector                        float scaleFactor   detector getScaleFactor                float originalScale    currentScale               currentScale    scaleFactor                Zoom in too much             if   currentScale  gt   maxScale                     currentScale    maxScale                  scaleFactor    maxScale   originalScale                 Zoom out too much             else if   currentScale  lt   minScale                     currentScale    minScale                  scaleFactor    minScale   originalScale                            matrix postScale scaleFactor scaleFactor                return true                        Override     protected void onMeasure  int widthMeasureSpec  int heightMeasureSpec                super onMeasure widthMeasureSpec  heightMeasureSpec            displayWidth   MeasureSpec getSize widthMeasureSpec            displayHeight   MeasureSpec getSize heightMeasureSpec           adjustScale               private void adjustScale                   Fit to display bounds with NO alpha space         float scale          float scaleX     displayWidth    bitmapWidth          float scaleY    displayHeight    bitmapHeight          scale   Math max scaleX  scaleY            matrix setScale scale  scale           setImageMatrix  matrix            currentScale   scale           minScale   scale             public void setMaxZoom float maxZoom   maxScale   maxZoom       public void setMinZoom float minZoom    minScale   minZoom

User · Answer

Just change ACTION MOVE EVENT in Chirag Raval Answer to set ZOOM IN LIMIT  float   values   new float 9   matrix getValues values                     0 37047964 is limit for zoom in                 if values Matrix MSCALE X  gt 0 37047964                        matrix set savedMatrix                       matrix postScale scale  scale  mid x  mid y                       view setImageMatrix matrix                    else if  scale gt 1                       matrix set savedMatrix                       matrix postScale scale  scale  mid x  mid y                       view setImageMatrix matrix

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Method to call the About amp support dialog   public void setupAboutSupport          try               The About amp Support AlertDialog is active         activeAboutSupport true           View messageView          int orientation this getResources   getConfiguration   orientation              Inflate the about message contents         messageView   getLayoutInflater   inflate R layout about support  null  false            ContextThemeWrapper ctw   new ContextThemeWrapper this  R style MyCustomTheme AlertDialog1           AlertDialog Builder builder   new AlertDialog Builder ctw           builder setIcon R mipmap ic launcher           builder setTitle R string action aboutSupport           builder setView messageView            TouchImageView imgDisplay    TouchImageView  messageView findViewById R id action infolinks about support           imgDisplay setMaxZoom 3f            Bitmap bitmap   BitmapFactory decodeResource getResources    R mipmap myinfolinks about support            int imageWidth   bitmap getWidth            int imageHeight   bitmap getHeight            int newWidth              Calculate the new About Support image width         if orientation  Configuration ORIENTATION PORTRAIT                    For 7  up to 10  tablets               if   getResources   getConfiguration   screenLayout  amp  Configuration SCREENLAYOUT SIZE MASK     Configuration SCREENLAYOUT SIZE XLARGE                if  SingletonMyInfoLinks isTablet                           newWidth   widthScreen -  two borders of about support layout and 20  of width Screen                  newWidth   widthScreen -   2   toPixels 8      int  widthScreen 0 2                  else newWidth   widthScreen -   2   toPixels 8      int  widthScreen 0 1               else                  For 7  up to 10  tablets               if   getResources   getConfiguration   screenLayout  amp  Configuration SCREENLAYOUT SIZE MASK     Configuration SCREENLAYOUT SIZE XLARGE                if  SingletonMyInfoLinks isTablet                    newWidth   widthScreen -   2   toPixels 8      int  widthScreen 0 5                   else newWidth   widthScreen -   2   toPixels 8      int  widthScreen 0 3                          Get the scale factor         float scaleFactor    float newWidth  float imageWidth             Calculate the new About Support image height         int newHeight    int  imageHeight   scaleFactor              Set the new bitmap corresponding the adjusted About Support image         bitmap   Bitmap createScaledBitmap bitmap  newWidth  newHeight  true               Rescale the image         imgDisplay setImageBitmap bitmap            dialogAboutSupport   builder show             TextView textViewVersion    TextView  dialogAboutSupport findViewById R id action strVersion           textViewVersion setText Html fromHtml getString R string aboutSupport text1     lt b gt   versionName   lt  b gt               TextView textViewDeveloperName    TextView  dialogAboutSupport findViewById R id action strDeveloperName           textViewDeveloperName setText Html fromHtml getString R string aboutSupport text2     lt b gt   SingletonMyInfoLinks developerName   lt  b gt               TextView textViewSupportEmail    TextView  dialogAboutSupport findViewById R id action strSupportEmail           textViewSupportEmail setText Html fromHtml getString R string aboutSupport text3      SingletonMyInfoLinks developerEmail             TextView textViewCompanyName    TextView  dialogAboutSupport findViewById R id action strCompanyName           textViewCompanyName setText Html fromHtml getString R string aboutSupport text4      SingletonMyInfoLinks companyName             Button btnOk    Button  dialogAboutSupport findViewById R id btnOK            btnOk setOnClickListener new View OnClickListener                  Override             public void onClick View v                    dialogAboutSupport dismiss                                       dialogAboutSupport setOnDismissListener new DialogInterface OnDismissListener                  Override             public void onDismiss final DialogInterface dialog                       the About  amp  Support AlertDialog is closed                 activeAboutSupport false                                     dialogAboutSupport getWindow   setBackgroundDrawable new ColorDrawable SingletonMyInfoLinks atualBackgroundColor                Effect that image appear slower               Only the fade in matters         AlphaAnimation fade out   new AlphaAnimation 1 0f  0 0f           AlphaAnimation fade in   new AlphaAnimation 0 0f  1 0f           AlphaAnimation a   false   fade out   fade in           a setDuration 2000      2 sec         a setFillAfter true      Maintain the visibility at the end of animation            Animation start         ImageView img    ImageView  messageView findViewById R id action infolinks about support           img startAnimation a          catch  Exception e              Log e SingletonMyInfoLinks appNameText   -     getLocalClassName           e getMessage

User · Answer

Try the following   package com example nwssugeoinformationmobileapplication  import android os Bundle  import android annotation SuppressLint  import android app Activity  import android content Intent  import android util FloatMath  import android util Log  import android view Menu  import android view MenuInflater  import android view MenuItem  import android view MotionEvent  import android view View OnTouchListener  import android widget TabHost  import android widget TabHost TabSpec  import android graphics Matrix  import android graphics PointF  import android graphics RectF  import android graphics drawable Drawable  import android view View  import android widget ImageView  public class MainActivity extends Activity implements  OnTouchListener        private static final String TAG    Touch       Matrix matrix   new Matrix        Matrix savedMatrix   new Matrix        static final int NONE   0      static final int DRAG   1      static final int ZOOM   2      int mode   NONE      PointF start   new PointF        PointF mid   new PointF        float oldDist   1f       private ImageView view      private float   matrixValues   new float 9       private float maxZoom      private float minZoom      private float height      private float width      private RectF viewRect        Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main            TabHost th    TabHost  findViewById  R id tabhost           th setup             TabSpec specs   th newTabSpec  tag1            specs setContent R id tab1           specs setIndicator  Map            th addTab specs             specs   th newTabSpec  tag2            specs setContent R id tab2           specs setIndicator  Search            th addTab specs             view    ImageView  findViewById R id imageView1           Drawable bitmap   getResources   getDrawable R drawable map           view setImageDrawable bitmap           view setOnTouchListener this             matrix setTranslate 1f  1f           view setImageMatrix matrix                     Override     public void onWindowFocusChanged boolean hasFocus        super onWindowFocusChanged hasFocus       if hasFocus       init                            private void init             maxZoom   2          minZoom   1f          height   view getDrawable   getIntrinsicHeight            width   view getDrawable   getIntrinsicWidth            viewRect   new RectF 0  0  view getWidth    view getHeight                     Override     public boolean onCreateOptionsMenu Menu menu            MenuInflater inflater   getMenuInflater            inflater inflate R menu menus  menu           return true                  public boolean onOptionsItemSelected MenuItem item             if item getItemId     R id item1               Log d  Tracks    Track Us was Clicked                 startActivity new Intent  MainActivity this  Tracklocation class                            if item getItemId     R id item2               Log d  Updates    Updates was Clicked                 startActivity new Intent  MainActivity this  Updates class                            if item getItemId     R id item3               Log d  About Us    About Us was Clicked                  startActivity new Intent  MainActivity this  Horoscope class                             return super onOptionsItemSelected item                  Override     public boolean onTouch View v  MotionEvent rawEvent            ImageView view    ImageView  v          view setScaleType ImageView ScaleType MATRIX           dumpEvent rawEvent          Handle touch events here        switch  rawEvent getAction    amp  MotionEvent ACTION MASK        case MotionEvent ACTION DOWN      savedMatrix set matrix       start set rawEvent getX    rawEvent getY         Log d TAG   mode DRAG        mode   DRAG      break      case MotionEvent ACTION POINTER DOWN      oldDist   spacing rawEvent       Log d TAG   oldDist     oldDist       if  oldDist  gt  10f        savedMatrix set matrix       midPoint mid  rawEvent       mode   ZOOM      Log d TAG   mode ZOOM              break      case MotionEvent ACTION UP      case MotionEvent ACTION POINTER UP      mode   NONE      Log d TAG   mode NONE        break      case MotionEvent ACTION MOVE      if  mode    DRAG        matrix set savedMatrix          limit pan     matrix getValues matrixValues       float currentY   matrixValues Matrix MTRANS Y       float currentX   matrixValues Matrix MTRANS X       float currentScale   matrixValues Matrix MSCALE X       float currentHeight   height   currentScale      float currentWidth   width   currentScale      float dx   rawEvent getX   - start x      float dy   rawEvent getY   - start y      float newX   currentX dx      float newY   currentY dy      RectF drawingRect   new RectF newX  newY  newX currentWidth  newY currentHeight       float diffUp   Math min viewRect bottom-drawingRect bottom  viewRect top-drawingRect top       float diffDown   Math max viewRect bottom-drawingRect bottom  viewRect top-drawingRect top       float diffLeft   Math min viewRect left-drawingRect left  viewRect right-drawingRect right       float diffRight   Math max viewRect left-drawingRect left  viewRect right-drawingRect right        if diffUp  gt  0        dy   diffUp            if diffDown  lt  0       dy   diffDown            if  diffLeft gt  0       dx    diffLeft            if diffRight  lt  0       dx    diffRight            matrix postTranslate dx  dy         else if  mode    ZOOM        float newDist   spacing rawEvent       Log d TAG   newDist     newDist       if  newDist  gt  10f        matrix set savedMatrix       float scale1   newDist   oldDist      matrix getValues matrixValues       float currentScale   matrixValues Matrix MSCALE X          limit zoom     if  scale1   currentScale  gt  maxZoom        scale1   maxZoom   currentScale        else if  scale1   currentScale  lt  minZoom        scale1   minZoom   currentScale            matrix postScale scale1  scale1  mid x  mid y                   break            view setImageMatrix matrix       return true               SuppressWarnings  deprecation       private void dumpEvent MotionEvent event            String names        DOWN    UP    MOVE    CANCEL    OUTSIDE            POINTER DOWN    POINTER UP    7     8     9              StringBuilder sb   new StringBuilder            int action   event getAction            int actionCode   action  amp  MotionEvent ACTION MASK          sb append  event ACTION    append names actionCode            if  actionCode    MotionEvent ACTION POINTER DOWN            actionCode    MotionEvent ACTION POINTER UP            sb append   pid    append          action  gt  gt  MotionEvent ACTION POINTER ID SHIFT           sb append                         sb append               for  int i   0  i  lt  event getPointerCount    i              sb append      append i           sb append   pid    append event getPointerId i            sb append       append  int  event getX i            sb append      append  int  event getY i            if  i   1  lt  event getPointerCount            sb append                         sb append               Log d TAG  sb toString                           Determine the space between the first two fingers            private float spacing MotionEvent event            float x   event getX 0  - event getX 1           float y   event getY 0  - event getY 1           return FloatMath sqrt x   x   y   y                         Calculate the mid point of the first two fingers             SuppressLint  FloatMath           private void midPoint PointF point  MotionEvent event            float x   event getX 0    event getX 1           float y   event getY 0    event getY 1           point set x   2  y   2

User · Answer

Here is my solution  it is based on  alexbirkett s solution   public class ZoomImageView extends ImageView       region   Static fields    static final int NONE   0  static final int DRAG   1  static final int ZOOM   2  static final int CLICK   3      endregion   Static fields       region   Fields    private int mode   NONE   private Matrix mMatrix   new Matrix     private PointF mLastTouch   new PointF    private PointF mStartTouch   new PointF    private float minScale   0 5f  private float maxScale   4f  private float   mCriticPoints   private float mScale   1f  private float mRight  private float mBottom  private float mOriginalBitmapWidth  private float mOriginalBitmapHeight   private ScaleGestureDetector mScaleDetector     endregion   Fields       region   Ctor   public ZoomImageView Context context        super context       init context      public ZoomImageView Context context  AttributeSet attrs        super context  attrs       init context      public ZoomImageView Context context  AttributeSet attrs  int defStyleAttr        super context  attrs  defStyleAttr       init context         endregion   Ctor       region   Overrider     Override protected void onMeasure int widthMeasureSpec  int heightMeasureSpec        super onMeasure widthMeasureSpec  heightMeasureSpec       int bmHeight   getBmHeight        int bmWidth   getBmWidth         float width   getMeasuredWidth        float height   getMeasuredHeight        float scale   1          If image is bigger then display fit it to screen      if  width  lt  bmWidth    height  lt  bmHeight            scale   width  gt  height   height   bmHeight   width   bmWidth             mMatrix setScale scale  scale       mScale   1f       mOriginalBitmapWidth   scale   bmWidth      mOriginalBitmapHeight   scale   bmHeight          Center the image     float redundantYSpace    height - mOriginalBitmapHeight       float redundantXSpace    width - mOriginalBitmapWidth        mMatrix postTranslate redundantXSpace   2  redundantYSpace   2        setImageMatrix mMatrix       Override public boolean onTouchEvent MotionEvent event        mScaleDetector onTouchEvent event        mMatrix getValues mCriticPoints       float translateX   mCriticPoints Matrix MTRANS X       float trnslateY   mCriticPoints Matrix MTRANS Y       PointF currentPoint   new PointF event getX    event getY          switch  event getAction                when one finger is touching           set the mode to DRAG         case MotionEvent ACTION DOWN              mLastTouch set event getX    event getY                 mStartTouch set mLastTouch               mode   DRAG              break            when two fingers are touching           set the mode to ZOOM         case MotionEvent ACTION POINTER DOWN              mLastTouch set event getX    event getY                 mStartTouch set mLastTouch               mode   ZOOM              break            when a finger moves           If mode is applicable move image         case MotionEvent ACTION MOVE                 if the mode is ZOOM or               if the mode is DRAG and already zoomed             if  mode    ZOOM     mode    DRAG  amp  amp  mScale  gt  minScale                         region   Move  image                   float deltaX   currentPoint x - mLastTouch x    x difference                 float deltaY   currentPoint y - mLastTouch y    y difference                 float scaleWidth   Math round mOriginalBitmapWidth   mScale     width after applying current scale                 float scaleHeight   Math round mOriginalBitmapHeight   mScale     height after applying current scale                     Move image to lef or right if its width is bigger than display width                 if  scaleWidth  gt  getWidth                          if  translateX   deltaX  gt  0                            deltaX   -translateX                        else if  translateX   deltaX  lt  -mRight                            deltaX   - translateX   mRight                                           else                       deltaX   0                                       Move image to up or bottom if its height is bigger than display height                 if  scaleHeight  gt  getHeight                          if  trnslateY   deltaY  gt  0                            deltaY   -trnslateY                        else if  trnslateY   deltaY  lt  -mBottom                            deltaY   - trnslateY   mBottom                                           else                       deltaY   0                                       move the image with the matrix                 mMatrix postTranslate deltaX  deltaY                     set the last touch location to the current                 mLastTouch set currentPoint x  currentPoint y                       endregion   Move image                             break            first finger is lifted         case MotionEvent ACTION UP              mode   NONE              int xDiff    int  Math abs currentPoint x - mStartTouch x               int yDiff    int  Math abs currentPoint y - mStartTouch y               if  xDiff  lt  CLICK  amp  amp  yDiff  lt  CLICK                  performClick                break             second finger is lifted         case MotionEvent ACTION POINTER UP              mode   NONE              break            setImageMatrix mMatrix       invalidate        return true       endregion   Overrides       region   Privates    private void init Context context        super setClickable true       mScaleDetector   new ScaleGestureDetector context  new ScaleListener         mCriticPoints   new float 9       setImageMatrix mMatrix       setScaleType ScaleType MATRIX      private int getBmWidth         Drawable drawable   getDrawable        if  drawable    null            return drawable getIntrinsicWidth              return 0     private int getBmHeight         Drawable drawable   getDrawable        if  drawable    null            return drawable getIntrinsicHeight              return 0       endregion   Privates       region   Internal classes    private class ScaleListener extends ScaleGestureDetector SimpleOnScaleGestureListener         Override     public boolean onScaleBegin ScaleGestureDetector detector            mode   ZOOM          return true              Override     public boolean onScale ScaleGestureDetector detector            float scaleFactor   detector getScaleFactor            float newScale   mScale   scaleFactor          if  newScale  lt  maxScale  amp  amp  newScale  gt  minScale                mScale   newScale              float width   getWidth                float height   getHeight                mRight    mOriginalBitmapWidth   mScale  - width              mBottom    mOriginalBitmapHeight   mScale  - height               float scaledBitmapWidth   mOriginalBitmapWidth   mScale              float scaledBitmapHeight   mOriginalBitmapHeight   mScale               if  scaledBitmapWidth  lt   width    scaledBitmapHeight  lt   height                    mMatrix postScale scaleFactor  scaleFactor  width   2  height   2                 else                   mMatrix postScale scaleFactor  scaleFactor  detector getFocusX    detector getFocusY                                     return true              endregion   Internal classes

User · Answer

You should put the image in webview and work with that  Zoom in   out controls are available in webview    http   xjaphx wordpress com 2011 09 18 using-webview-as-a-image-zoom-view-control  http   androidforums com android-lounge 121522-how-display-image-sdcard-webview html

User · Answer

Step 1   First you add dependencies in build gradle Module app  file   dependencies         implementation  com jsibbold zoomage 1 2 0           Step 2  Next create a class     ImageFullScreenFragment java   public class ImageFullScreenFragment      private ZoomageView ImageZoomageView        Override     public View onCreateView LayoutInflater inflater  ViewGroup container                               Bundle savedInstanceState               Inflate the layout for this fragment         View view   null         try            view   inflater inflate R layout fragment image full screen  container  false               ImageZoomageView   view findViewById R id imageViewImageFullScreen               ImageZoomageView setImageResource R drawable image               catch  Exception e                 e printStackTrace                   return view       Step 3   Next create a layout xml file     fragment image full screen xml    lt  xml version  1 0  encoding  utf-8   gt   lt RelativeLayout xmlns android  http   schemas android com apk res android      xmlns tools  http   schemas android com tools      android layout width  match parent      android layout height  match parent      android padding  8dp      xmlns app  http   schemas android com apk res-auto  gt        lt com jsibbold zoomage ZoomageView         android layout width  match parent          android layout height  match parent          app zoomage restrictBounds  false          app zoomage animateOnReset  true          app zoomage autoResetMode  UNDER          app zoomage autoCenter  true          app zoomage zoomable  true          app zoomage translatable  true          app zoomage minScale  0 6          app zoomage maxScale  8          android id    id imageViewImageFullScreen            gt    lt  RelativeLayout gt    OutPut -

[android] Android ImageView Zoom-in and Zoom-Out

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