Auto-fit TextView for Android

Question

Background  Many times we need to auto-fit the font of the TextView to the boundaries given to it   The problem  Sadly  even though there are many threads and posts  and suggested solutions  talking about this problem  example here  here and here   none of them actually work well   That s why  I ve decided to test each of them till I find the real deal   I think that the requirements from such a textView should be    Should allow using any font  typeface  style  and set of characters  Should handle both width and height No truncation unless text cannot fit because of the limitation  we ve given to it  example  too long text  too small available size   However  we could request for horizontal vertical scrollbar if we wish  just for those cases  Should allow multi-line or single-line  In case of multi-line  allow max  amp  min lines  Should not be slow in computation  Using a loop for finding the best size  At least optimize it and don t increment your sampling by 1 each time  In case of multi-line  should allow to prefer resizing or using more lines  and or allow to choose the lines ourselves by using the   n  character    What I ve tried  I ve tried so many samples  including those of the links  I ve written about   and I ve also tried to modify them to handle the cases  I ve talked about  but none really work   I ve made a sample project that allows me to visually see if the TextView auto-fits correctly   Currently  my sample project only randomize the text  the English alphabet plus digits  and the size of the textView  and let it stay with single line  but even this doesn t work well on any of the samples I ve tried   Here s the code  also available here    File res layout activity main xml   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  tools context   MainActivity  gt     lt Button android id    id button1  android layout width  wrap content      android layout height  wrap content      android layout alignParentBottom  true      android layout centerHorizontal  true  android text  Button    gt     lt FrameLayout android layout width  match parent      android layout height  wrap content  android layout above    id button1      android layout alignParentLeft  true  android background   ffff0000      android layout alignParentRight  true  android id    id container      android layout alignParentTop  true    gt    lt  RelativeLayout gt    File src     MainActivity java  public class MainActivity extends Activity       private final Random         random             new Random      private static final String ALLOWED CHARACTERS   qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890       Override   protected void onCreate final Bundle savedInstanceState            super onCreate savedInstanceState       setContentView R layout activity main       final ViewGroup container  ViewGroup findViewById R id container       findViewById R id button1  setOnClickListener new OnClickListener                    Override         public void onClick final View v                        container removeAllViews              final int maxWidth container getWidth              final int maxHeight container getHeight              final FontFitTextView fontFitTextView new FontFitTextView MainActivity this             final int width  random nextInt maxWidth  1            final int height  random nextInt maxHeight  1            fontFitTextView setLayoutParams new LayoutParams width height              fontFitTextView setSingleLine              fontFitTextView setBackgroundColor 0xff00ff00             final String text getRandomText              fontFitTextView setText text             container addView fontFitTextView             Log d  DEBUG   width   width   height   height   text   text                                  private String getRandomText             final int textLength  random nextInt 20  1      final StringBuilder builder new StringBuilder        for int i 0 i lt textLength   i        builder append ALLOWED CHARACTERS charAt  random nextInt ALLOWED CHARACTERS length           return builder toString                The question  Does anybody know of a solution for this common problem that actually work   Even a solution that has much less features that what I ve written about  for example one that has just a constant number of lines of text  and adjusts its font according to its size  yet never have weird glitches and having the text get too large small compared to its available space     GitHub project  Since this is such an important TextView  I ve decided to publish a library  so that everyone could easily use it  and contribute to it  here

User · Answer

Try adding LayoutParams and MaxWidth and MaxHeight to the TextView  It will force the layout to respect the parent container and not overflow   textview setLayoutParams new LayoutParams LinearLayout MATCH PARENT LinearLayout WRAP CONTENT     int GeneralApproxWidthOfContainer   400  int GeneralApproxHeightOfContainer   600  textview setMaxWidth 400   textview setMaxHeight 600

User · Answer

From June 2018 Android officially support this feature for Android 4 0  API level 14  and higher   With Android 8 0  API level 26  and higher    setAutoSizeTextTypeUniformWithConfiguration int autoSizeMinTextSize  int autoSizeMaxTextSize           int autoSizeStepGranularity  int unit     Android versions prior to Android 8 0  API level 26    TextViewCompat setAutoSizeTextTypeUniformWithConfiguration TextView textView  int autoSizeMinTextSize  int autoSizeMaxTextSize  int autoSizeStepGranularity  int unit    Check out my detail answer

User · Answer

After i tried Android official Autosizing TextView  i found if your Android version is prior to Android 8 0  API level 26   you need use android support v7 widget AppCompatTextView  and make sure your support library version is above 26 0 0  Example    lt android support v7 widget AppCompatTextView     android layout width  130dp      android layout height  32dp      android maxLines  1      app autoSizeMaxTextSize  22sp      app autoSizeMinTextSize  12sp      app autoSizeStepGranularity  2sp      app autoSizeTextType  uniform    gt    update   According to  android-developer s reply  i check the AppCompatActivity source code  and found these two lines in onCreate   final AppCompatDelegate delegate   getDelegate     delegate installViewFactory     and in AppCompatDelegateImpl s createView      if  mAppCompatViewInflater    null            mAppCompatViewInflater   new AppCompatViewInflater            it use AppCompatViewInflater inflater view  when AppCompatViewInflater createView it will use AppCompatTextView for  TextView    public final View createView                View view   null      switch  name            case  TextView               view   new AppCompatTextView context  attrs               break          case  ImageView               view   new AppCompatImageView context  attrs               break          case  Button               view   new AppCompatButton context  attrs               break              In my project i don t use AppCompatActivity  so i need  use  lt android support v7 widget AppCompatTextView gt  in xml

User · Answer

Thanks to MartinH s simple fix here  this code also takes care of android drawableLeft  android drawableRight  android drawableTop and android drawableBottom tags     My answer here should make you happy Auto Scale TextView Text to Fit within Bounds  I have modified your test case    Override protected void onCreate final Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main       final ViewGroup container    ViewGroup  findViewById R id container       findViewById R id button1  setOnClickListener new OnClickListener              Override         public void onClick final View v                container removeAllViews                final int maxWidth   container getWidth                final int maxHeight   container getHeight                final AutoResizeTextView fontFitTextView   new AutoResizeTextView MainActivity this               final int width    random nextInt maxWidth    1              final int height    random nextInt maxHeight    1              fontFitTextView setLayoutParams new FrameLayout LayoutParams                      width  height                int maxLines    random nextInt 4    1              fontFitTextView setMaxLines maxLines               fontFitTextView setTextSize 500     max size             fontFitTextView enableSizeCache false               fontFitTextView setBackgroundColor 0xff00ff00               final String text   getRandomText                fontFitTextView setText text               container addView fontFitTextView               Log d  DEBUG    width     width     height     height                         text     text     maxLines     maxLines                         I am posting code here at per android developer s request   Final effect     Sample Layout file    lt LinearLayout xmlns android  http   schemas android com apk res android  android layout width  wrap content  android layout height  wrap content  android orientation  vertical  android padding  16dp   gt    lt com vj widgets AutoResizeTextView     android layout width  match parent      android layout height  100dp      android ellipsize  none      android maxLines  2      android text  Auto Resized Text  max 2 lines      android textSize  100sp    gt   lt  -- maximum size -- gt    lt com vj widgets AutoResizeTextView     android layout width  match parent      android layout height  100dp      android ellipsize  none      android gravity  center      android maxLines  1      android text  Auto Resized Text  max 1 line      android textSize  100sp    gt   lt  -- maximum size -- gt    lt com vj widgets AutoResizeTextView     android layout width  match parent      android layout height  wrap content      android text  Auto Resized Text      android textSize  500sp    gt   lt  -- maximum size -- gt    lt  LinearLayout gt    And the Java code   import android annotation TargetApi  import android content Context  import android content res Resources  import android graphics RectF  import android os Build  import android text Layout Alignment  import android text StaticLayout  import android text TextPaint  import android util AttributeSet  import android util SparseIntArray  import android util TypedValue  import android widget TextView   public class AutoResizeTextView extends TextView       private interface SizeTester                                      param suggestedSize                       Size of text to be tested             param availableSpace                       available space in which text must fit             return an integer  lt  0 if after applying   code suggestedSize  to                    text  it takes less space than   code availableSpace    gt  0                    otherwise                     public int onTestSize int suggestedSize  RectF availableSpace              private RectF mTextRect   new RectF         private RectF mAvailableSpaceRect       private SparseIntArray mTextCachedSizes       private TextPaint mPaint       private float mMaxTextSize       private float mSpacingMult   1 0f       private float mSpacingAdd   0 0f       private float mMinTextSize   20       private int mWidthLimit       private static final int NO LINE LIMIT   -1      private int mMaxLines       private boolean mEnableSizeCache   true      private boolean mInitializedDimens       public AutoResizeTextView Context context            super context           initialize               public AutoResizeTextView Context context  AttributeSet attrs            super context  attrs           initialize               public AutoResizeTextView Context context  AttributeSet attrs  int defStyle            super context  attrs  defStyle           initialize               private void initialize             mPaint   new TextPaint getPaint             mMaxTextSize   getTextSize            mAvailableSpaceRect   new RectF            mTextCachedSizes   new SparseIntArray            if  mMaxLines    0                   no value was assigned during construction             mMaxLines   NO LINE LIMIT                        Override     public void setTextSize float size            mMaxTextSize   size          mTextCachedSizes clear            adjustTextSize                Override     public void setMaxLines int maxlines            super setMaxLines maxlines           mMaxLines   maxlines          adjustTextSize               public int getMaxLines             return mMaxLines              Override     public void setSingleLine             super setSingleLine            mMaxLines   1          adjustTextSize                Override     public void setSingleLine boolean singleLine            super setSingleLine singleLine           if  singleLine                mMaxLines   1            else               mMaxLines   NO LINE LIMIT                    adjustTextSize                Override     public void setLines int lines            super setLines lines           mMaxLines   lines          adjustTextSize                Override     public void setTextSize int unit  float size            Context c   getContext            Resources r           if  c    null              r   Resources getSystem            else             r   c getResources            mMaxTextSize   TypedValue applyDimension unit  size                  r getDisplayMetrics             mTextCachedSizes clear            adjustTextSize                Override     public void setLineSpacing float add  float mult            super setLineSpacing add  mult           mSpacingMult   mult          mSpacingAdd   add                        Set the lower text size limit and invalidate the view                param minTextSize             public void setMinTextSize float minTextSize            mMinTextSize   minTextSize          adjustTextSize               private void adjustTextSize             if   mInitializedDimens                return                    int startSize    int  mMinTextSize          int heightLimit   getMeasuredHeight   - getCompoundPaddingBottom                   - getCompoundPaddingTop            mWidthLimit   getMeasuredWidth   - getCompoundPaddingLeft                   - getCompoundPaddingRight            mAvailableSpaceRect right   mWidthLimit          mAvailableSpaceRect bottom   heightLimit          super setTextSize                  TypedValue COMPLEX UNIT PX                  efficientTextSizeSearch startSize   int  mMaxTextSize                          mSizeTester  mAvailableSpaceRect               private final SizeTester mSizeTester   new SizeTester              TargetApi Build VERSION CODES JELLY BEAN           Override         public int onTestSize int suggestedSize  RectF availableSPace                mPaint setTextSize suggestedSize               String text   getText   toString                boolean singleline   getMaxLines      1              if  singleline                    mTextRect bottom   mPaint getFontSpacing                    mTextRect right   mPaint measureText text                 else                   StaticLayout layout   new StaticLayout text  mPaint                          mWidthLimit  Alignment ALIGN NORMAL  mSpacingMult                          mSpacingAdd  true                       Return early if we have more lines                 if  getMaxLines      NO LINE LIMIT                          amp  amp  layout getLineCount    gt  getMaxLines                          return 1                                    mTextRect bottom   layout getHeight                    int maxWidth   -1                  for  int i   0  i  lt  layout getLineCount    i                          if  maxWidth  lt  layout getLineWidth i                             maxWidth    int  layout getLineWidth i                                                           mTextRect right   maxWidth                             mTextRect offsetTo 0  0               if  availableSPace contains mTextRect                         May be too small  don t worry we will find the best match                 return -1                else                      too big                 return 1                                                 Enables or disables size caching  enabling it will improve performance        where you are animating a value inside TextView  This stores the font        size against getText   length   Be careful though while enabling it as 0        takes more space than 1 on some fonts and so on                 param enable                   Enable font size caching             public void enableSizeCache boolean enable            mEnableSizeCache   enable          mTextCachedSizes clear            adjustTextSize getText   toString                private int efficientTextSizeSearch int start  int end              SizeTester sizeTester  RectF availableSpace            if   mEnableSizeCache                return binarySearch start  end  sizeTester  availableSpace                     int key   getText   toString   length            int size   mTextCachedSizes get key           if  size    0                return size                    size   binarySearch start  end  sizeTester  availableSpace           mTextCachedSizes put key  size           return size             private static int binarySearch int start  int end  SizeTester sizeTester              RectF availableSpace            int lastBest   start          int lo   start          int hi   end - 1          int mid   0          while  lo  lt   hi                mid    lo   hi   gt  gt  gt  1              int midValCmp   sizeTester onTestSize mid  availableSpace               if  midValCmp  lt  0                    lastBest   lo                  lo   mid   1                else if  midValCmp  gt  0                    hi   mid - 1                  lastBest   hi                else                   return mid                                     Make sure to return the last best             This is what should always be returned          return lastBest               Override     protected void onTextChanged final CharSequence text  final int start              final int before  final int after            super onTextChanged text  start  before  after           adjustTextSize                Override     protected void onSizeChanged int width  int height  int oldwidth              int oldheight            mInitializedDimens   true          mTextCachedSizes clear            super onSizeChanged width  height  oldwidth  oldheight           if  width    oldwidth    height    oldheight                adjustTextSize                        Warning   Beware of this resolved bug in Android nbsp 3 1  Honeycomb  though

User · Answer

Convert the text view to an image  and the scale the image within the boundaries   Here s an example on how to convert a view to an Image  Converting a view to Bitmap without displaying it in Android   The problem is  your text will not be selectable  but it should do the trick  I haven t tried it  so I m not sure how it would look  because of the scaling

User · Answer

Ok I have used the last week to massively rewrite my code to precisely fit your test  You can now copy this 1 1 and it will immediately work - including setSingleLine    Please remember to adjust MIN TEXT SIZE and MAX TEXT SIZE if you re going for extreme values  Converging algorithm looks like this  for  float testSize   upperTextSize - lowerTextSize   gt  mThreshold             Go to the mean value        testSize    upperTextSize   lowerTextSize    2              inflate the dummy TextView by setting a scaled textSize and the text        mTestView setTextSize TypedValue COMPLEX UNIT SP  testSize   mScaledDensityFactor       mTestView setText text               call measure to find the current values that the text WANTS to occupy     mTestView measure MeasureSpec UNSPECIFIED  MeasureSpec UNSPECIFIED       int tempHeight   mTestView getMeasuredHeight                decide whether those values are appropriate      if  tempHeight  gt   targetFieldHeight            upperTextSize   testSize     Font is too big  decrease upperSize           else           lowerTextSize   testSize     Font is too small  increase lowerSize          And the whole class can be found here  The result is very flexible now  This works the same declared in xml like so   lt com example myProject AutoFitText     android id  quot   id textView quot      android layout width  quot match parent quot      android layout height  quot 0dp quot      android layout weight  quot 4 quot      android text  quot  string LoremIpsum quot    gt       as well as built programmatically like in your test  I really hope you can use this now  You can call setText CharSequence text  now to use it by the way  The class takes care of stupendously rare exceptions and should be rock-solid  The only thing that the algorithm does not support yet is   Calls to setMaxLines x  where x  gt   2  But I have added extensive comments to help you build this if you wish to   Please note  If you just use this normally without limiting it to a single line then there might be word-breaking as you mentioned before  This is an Android feature  not the fault of the AutoFitText  Android will always break words that are too long for a TextView and it s actually quite a convenience  If you want to intervene here than please see my comments and code starting at line 203  I have already written an adequate split and the recognition for you  all you d need to do henceforth is to devide the words and then modify as you wish  In conclusion  You should highly consider rewriting your test to also support space chars  like so  final Random  random   new Random    final String ALLOWED CHARACTERS    quot qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890 quot   final int textLength    random nextInt 80    20  final StringBuilder builder   new StringBuilder    for  int i   0  i  lt  textLength    i        if  i   7    0  amp  amp  i    0            builder append  quot   quot              builder append ALLOWED CHARACTERS charAt  random nextInt ALLOWED CHARACTERS length           AutoFitText  findViewById R id textViewMessage   setText builder toString      This will produce very beutiful  and more realistic  results  You will find commenting to get you started in this matter as well  Good luck and best regards

User · Answer

Quick fix for the issue described by  Malachiasz  I ve fixed the issue by adding custom support for this in the auto resize class   public void setTextCompat final CharSequence text        setTextCompat text  BufferType NORMAL      public void setTextCompat final CharSequence text  BufferType type           Quick fix for Android Honeycomb and Ice Cream Sandwich which sets the text only on the first call     if  Build VERSION SDK INT  gt   Build VERSION CODES HONEYCOMB MR1  amp  amp          Build VERSION SDK INT  lt   Build VERSION CODES ICE CREAM SANDWICH MR1            super setText DOUBLE BYTE WORDJOINER   text   DOUBLE BYTE WORDJOINER  type         else           super setText text  type             Override public CharSequence getText         String originalText   super getText   toString        if  Build VERSION SDK INT  gt   Build VERSION CODES HONEYCOMB MR1  amp  amp          Build VERSION SDK INT  lt   Build VERSION CODES ICE CREAM SANDWICH MR1               We try to remove the word joiners we added using compat method - if none found - this will do nothing          return originalText replaceAll DOUBLE BYTE WORDJOINER             else           return originalText            Just call yourView setTextCompat newTextValue  instead of yourView setText newTextValue

User · Answer

Try this  TextWatcher changeText   new TextWatcher           Override             public void onTextChanged CharSequence s  int start  int before  int count                    tv3 setText et getText   toString                     tv3 post new Runnable                                     Override                     public void run                         while tv3 getLineCount    gt   3                                                    tv3 setTextSize  tv3 getTextSize   -1                                                                                                                        Override public void beforeTextChanged CharSequence s  int start  int count  int after                   Override public void afterTextChanged Editable s

User · Answer

If you are looking for something easier    public MyTextView extends TextView       public void resize String text  float textViewWidth  float textViewHeight           Paint p   new Paint           Rect bounds   new Rect           p setTextSize 1          p getTextBounds text  0  text length    bounds          float widthDifference    textViewWidth  bounds width           float heightDifference    textViewHeight          textSize   Math min widthDifference  heightDifference          setTextSize TypedValue COMPLEX UNIT PX  textSize

User · Answer

There s now an official solution to this problem  Autosizing TextViews introduced with Android O are available in the Support Library 26 and is backwards compatible all the way down to Android 4 0   https   developer android com preview features autosizing-textview html  I m not sure why https   stackoverflow com a 42940171 47680 which also included this information was deleted by an admin

User · Answer

I ll explain how works this attribute lower android versions step by step   1- Import android support library 26 x x on your project gradle file  If there is no support library on IDE  they will download automatically   dependencies       compile  com android support support-v4 26 1 0      compile  com android support appcompat-v7 26 1 0      compile  com android support support-v13 26 1 0     allprojects       repositories           jcenter           maven               url  https   maven google com                      2- Open your layout XML file and refactor like this tag your TextView  This scenario is  when incrased font size on system  fit text to avaliable width  not word wrap    lt android support v7 widget AppCompatTextView             android id    id textViewAutoSize              android layout width  match parent              android layout height  25dp              android ellipsize  none              android text  Auto size text with compatible lower android versions               android textSize  12sp              app autoSizeMaxTextSize  14sp              app autoSizeMinTextSize  4sp              app autoSizeStepGranularity  0 5sp              app autoSizeTextType  uniform    gt

User · Answer

Below is avalancha TextView with added functionality for custom Font   Usage    lt  xml version  1 0  encoding  utf-8   gt   lt FrameLayout xmlns android  http   schemas android com apk res android      xmlns foo  http   schemas android com apk res-auto      android layout width  wrap content      android layout height  match parent   gt                    lt de meinprospekt androidhd view AutoFitText                 android layout width  wrap content                  android layout height  10dp                  android text  Small Text                  android textColor   FFFFFF                  android textSize  100sp                  foo customFont  fonts Roboto-Light ttf    gt    lt  FrameLayout gt    Don t forget to add  xmlns foo  http   schemas android com apk res-auto   Font should be in assets firectory  import java util ArrayList  import java util List   import android annotation SuppressLint  import android content Context  import android content res TypedArray  import android graphics Paint  import android graphics Typeface  import android os Build  import android util AttributeSet  import android util Log  import android util TypedValue  import android view View  import android view ViewGroup LayoutParams  import android view ViewTreeObserver  import android view ViewTreeObserver OnGlobalLayoutListener  import android widget TextView  import de meinprospekt androidhd R  import de meinprospekt androidhd adapter BrochuresHorizontalAdapter  import de meinprospekt androidhd util LOG          https   stackoverflow com a 16174468 2075875 This class builds a new android Widget named AutoFitText which can be used instead of a TextView to    have the text font size in it automatically fit to match the screen width  Credits go largely to Dunni  gjpc  gregm and speedplane from    Stackoverflow  method has been  style-  optimized and rewritten to match android coding standards and our MBC  This version upgrades the original     AutoFitTextView  to now also be adaptable to height and to accept the different TextView types  Button  TextClock etc           author pheuschk     createDate  18 04 2013        combined with  https   stackoverflow com a 7197867 2075875      SuppressWarnings  unused   public class AutoFitText extends TextView        private static final String TAG   AutoFitText class getSimpleName             Global min and max for text size  Remember  values are in pixels         private final int MIN TEXT SIZE   10      private final int MAX TEXT SIZE   400           Flag for singleLine        private boolean mSingleLine   false                  A dummy   link TextView  to test the text size without actually showing anything to the user             private TextView mTestView                  A dummy   link Paint  to test the text size without actually showing anything to the user             private Paint mTestPaint                  Scaling factor for fonts  It s a method of calculating independently     from the actual density of the screen that is used so users have the        same experience on different devices  We will use DisplayMetrics in the Constructor to get the value of the factor and then calculate SP from        pixel values             private float mScaledDensityFactor                  Defines how close we want to be to the factual size of the Text-field  Lower values mean higher precision but also exponentially higher        computing cost  more loop runs              private final float mThreshold   0 5f                  Constructor for call without attributes -- gt  invoke constructor with AttributeSet null                 param context             public AutoFitText Context context            this context  null              public AutoFitText Context context  AttributeSet attrs            super context  attrs           init context  attrs              public AutoFitText Context context  AttributeSet attrs  int defStyle            super context  attrs  defStyle           init context  attrs              private void init Context context  AttributeSet attrs              TextViewPlus part https   stackoverflow com a 7197867 2075875         TypedArray a   context obtainStyledAttributes attrs  R styleable AutoFitText           String customFont   a getString R styleable AutoFitText customFont           setCustomFont context  customFont           a recycle                AutoFitText part         mScaledDensityFactor   context getResources   getDisplayMetrics   scaledDensity          mTestView   new TextView context            mTestPaint   new Paint            mTestPaint set this getPaint              this getViewTreeObserver   addOnGlobalLayoutListener new OnGlobalLayoutListener                   Override             public void onGlobalLayout                        make an initial call to onSizeChanged to make sure that refitText is triggered                 onSizeChanged AutoFitText this getWidth    AutoFitText this getHeight    0  0                      Remove the LayoutListener immediately so we don t run into an infinite loop                   AutoFitText this getViewTreeObserver   removeOnGlobalLayoutListener this                   removeOnGlobalLayoutListener AutoFitText this  this                                        public boolean setCustomFont Context ctx  String asset            Typeface tf   null          try           tf   Typeface createFromAsset ctx getAssets    asset               catch  Exception e                LOG e TAG   Could not get typeface    e getMessage                 return false                     setTypeface tf             return true              SuppressLint  NewApi       public static void removeOnGlobalLayoutListener View v  ViewTreeObserver OnGlobalLayoutListener listener           if  Build VERSION SDK INT  lt  16                v getViewTreeObserver   removeGlobalOnLayoutListener listener             else               v getViewTreeObserver   removeOnGlobalLayoutListener listener                                   Main method of this widget  Resizes the font so the specified text fits in the text box assuming the text box has the specified width  This is        done via a dummy text view that is refit until it matches the real target width and height up to a certain threshold factor                 param targetFieldWidth The width that the TextView currently has and wants filled         param targetFieldHeight The width that the TextView currently has and wants filled             private void refitText String text  int targetFieldWidth  int targetFieldHeight                Variables need to be visible outside the loops for later use  Remember size is in pixels         float lowerTextSize   MIN TEXT SIZE          float upperTextSize   MAX TEXT SIZE              Force the text to wrap  In principle this is not necessary since the dummy TextView            already does this for us but in rare cases adding this line can prevent flickering         this setMaxWidth targetFieldWidth               Padding should not be an issue since we never define it programmatically in this app            but just to to be sure we cut it off here         targetFieldWidth   targetFieldWidth - this getPaddingLeft   - this getPaddingRight            targetFieldHeight   targetFieldHeight - this getPaddingTop   - this getPaddingBottom                Initialize the dummy with some params  that are largely ignored anyway  but this is            mandatory to not get a NullPointerException          mTestView setLayoutParams new LayoutParams targetFieldWidth  targetFieldHeight                maxWidth is crucial  Otherwise the text would never line wrap but blow up the width         mTestView setMaxWidth targetFieldWidth            if  mSingleLine                   the user requested a single line  This is very easy to do since we primarily need to                respect the width  don t have to break  don t have to measure                                              Converging algorithm 1                                                  for  float testSize   upperTextSize - lowerTextSize   gt  mThreshold                         Go to the mean value                    testSize    upperTextSize   lowerTextSize    2                   mTestView setTextSize TypedValue COMPLEX UNIT SP  testSize   mScaledDensityFactor                   mTestView setText text                   mTestView measure MeasureSpec UNSPECIFIED  MeasureSpec UNSPECIFIED                    if  mTestView getMeasuredWidth    gt   targetFieldWidth                        upperTextSize   testSize     Font is too big  decrease upperSize                   else                       lowerTextSize   testSize     Font is too small  increase lowerSize                                                                                                                                                      In rare cases with very little letters and width  gt  height we have vertical overlap              mTestView measure MeasureSpec UNSPECIFIED  MeasureSpec UNSPECIFIED                if  mTestView getMeasuredHeight    gt  targetFieldHeight                    upperTextSize   lowerTextSize                  lowerTextSize   MIN TEXT SIZE                                                Converging algorithm 1 5                                                for  float testSize   upperTextSize - lowerTextSize   gt  mThreshold                             Go to the mean value                        testSize    upperTextSize   lowerTextSize    2                       mTestView setTextSize TypedValue COMPLEX UNIT SP  testSize   mScaledDensityFactor                       mTestView setText text                       mTestView measure MeasureSpec UNSPECIFIED  MeasureSpec UNSPECIFIED                        if  mTestView getMeasuredHeight    gt   targetFieldHeight                            upperTextSize   testSize     Font is too big  decrease upperSize                       else                           lowerTextSize   testSize     Font is too small  increase lowerSize                                                                                                                                                                      else                                         Converging algorithm 2                                                         Upper and lower size converge over time  As soon as they re close enough the loop                stops                TODO probe the algorithm for cost  ATM possibly O n 2   and optimize if possible             for  float testSize   upperTextSize - lowerTextSize   gt  mThreshold                         Go to the mean value                    testSize    upperTextSize   lowerTextSize    2                          inflate the dummy TextView by setting a scaled textSize and the text                    mTestView setTextSize TypedValue COMPLEX UNIT SP  testSize   mScaledDensityFactor                   mTestView setText text                           call measure to find the current values that the text WANTS to occupy                 mTestView measure MeasureSpec UNSPECIFIED  MeasureSpec UNSPECIFIED                   int tempHeight   mTestView getMeasuredHeight                       int tempWidth   mTestView getMeasuredWidth                        LOG debug  Measured      tempWidth    x    tempHeight                      LOG debug  TextSize      testSize   mScaledDensityFactor                           decide whether those values are appropriate                  if  tempHeight  gt   targetFieldHeight                        upperTextSize   testSize     Font is too big  decrease upperSize                   else                       lowerTextSize   testSize     Font is too small  increase lowerSize                                                                                                                                                      It is possible that a single word is wider than the box  The Android system would                wrap this for us  But if you want to decide fo yourself where exactly to break or to                add a hyphen or something than you re going to want to implement something like this              mTestPaint setTextSize lowerTextSize               List lt String gt  words   new ArrayList lt String gt                  for  String s   text split                         Log i  tag    Word      s                   words add s                             for  String word   words                    if  mTestPaint measureText word   gt   targetFieldWidth                        List lt String gt  pieces   new ArrayList lt String gt                            pieces   breakWord word  mTestPaint measureText word   targetFieldWidth                           Add code to handle the pieces here                                                                      We are now at most the value of threshold away from the actual size  To rather undershoot than overshoot use the lower value  To match            different screens convert to SP first  See   link http   developer android com guide topics resources more-resources html Dimension  for            more details                     this setTextSize TypedValue COMPLEX UNIT SP  lowerTextSize   mScaledDensityFactor           return                        This method receives a call upon a change in text content of the TextView  Unfortunately it is also called - among others - upon text size        change which means that we MUST NEVER CALL   link  refitText String   from this method  Doing so would result in an endless loop that would        ultimately result in a stack overflow and termination of the application                So for the time being this method does absolutely nothing  If you want to notify the view of a changed text call   link  setText CharSequence                Override     protected void onTextChanged CharSequence text  int start  int lengthBefore  int lengthAfter               Super implementation is also intentionally empty so for now we do absolutely nothing here         super onTextChanged text  start  lengthBefore  lengthAfter               Override     protected void onSizeChanged int width  int height  int oldWidth  int oldHeight            if  width    oldWidth  amp  amp  height    oldHeight                refitText this getText   toString    width  height                                   This method is guaranteed to be called by   link TextView setText CharSequence   immediately  Therefore we can safely add our modifications        here and then have the parent class resume its work  So if text has changed you should always call   link TextView setText CharSequence   or          link TextView setText CharSequence  BufferType   if you know whether the   link BufferType  is normal  editable or spannable  Note  the        method will default to   link BufferType NORMAL  if you don t pass an argument               Override     public void setText CharSequence text  BufferType type             int targetFieldWidth   this getWidth            int targetFieldHeight   this getHeight             if  targetFieldWidth  lt   0    targetFieldHeight  lt   0    text equals                       Log v  tag    Some values are empty  AutoFitText was not able to construct properly              else               refitText text toString    targetFieldWidth  targetFieldHeight                     super setText text  type                         TODO add sensibility for   link  setMaxLines int   invocations              Override     public void setMaxLines int maxLines               TODO Implement support for this  This could be relatively easy  The idea would probably            be to manipulate the targetHeight in the refitText-method and then have the algorithm do            its job business as usual  Nonetheless  remember the height will have to be lowered            dynamically as the font size shrinks so it won t be a walk in the park still         if  maxLines    1                this setSingleLine true             else               throw new UnsupportedOperationException  MaxLines    1 are not implemented in AutoFitText yet  use TextView instead                          Override     public void setSingleLine boolean singleLine               save the requested value in an instance variable to be able to decide later         mSingleLine   singleLine          super setSingleLine singleLine             known bugs  Doesn t work with Android 4 03 - fonts are invisible or very small  original avalancha doesn t work too  below is workaround for that bug  https   stackoverflow com a 21851239 2075875

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My requirement is to    Click on the ScalableTextView Open a listActivity and display various length string items  Select a text from list  Set the text back to the ScalableTextView in another activity     I referred the link  Auto Scale TextView Text to Fit within Bounds  including comments  and also the DialogTitle java  I found that the solution provided is nice and simple but it does not dynamically change the size of the text box  It works great when the selected text length from the list view is greater in size than the existing text lenght in the ScalableTextView  When selected the text having length smaller than the existing text in the ScalableTextView  it do not increase the size of the text  showing the text in the smaller size    I modified the ScalableTextView java to readjust the text size based on the text length  Here is my ScalableTextView java  public class ScalableTextView extends TextView   float defaultTextSize   0 0f   public ScalableTextView Context context  AttributeSet attrs  int defStyle        super context  attrs  defStyle       setSingleLine        setEllipsize TruncateAt END       defaultTextSize   getTextSize       public ScalableTextView Context context  AttributeSet attrs        super context  attrs       setSingleLine        setEllipsize TruncateAt END       defaultTextSize   getTextSize       public ScalableTextView Context context        super context       setSingleLine        setEllipsize TruncateAt END       defaultTextSize   getTextSize        Override protected void onMeasure int widthMeasureSpec  int heightMeasureSpec        setTextSize TypedValue COMPLEX UNIT PX  defaultTextSize       super onMeasure widthMeasureSpec  heightMeasureSpec        final Layout layout   getLayout        if  layout    null                final int lineCount   layout getLineCount            if  lineCount  gt  0                        int ellipsisCount   layout getEllipsisCount lineCount - 1               while  ellipsisCount  gt  0                                final float textSize   getTextSize                        textSize is already expressed in pixels                 setTextSize TypedValue COMPLEX UNIT PX   textSize - 1                     super onMeasure widthMeasureSpec  heightMeasureSpec                   ellipsisCount   layout getEllipsisCount lineCount - 1                                       Happy Coding

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I ve modified M-WaJeEh s answer a bit to take into account compound drawables on the sides   The getCompoundPaddingXXXX   methods return padding of the view   drawable space  See for example  TextView getCompoundPaddingLeft    Issue  This fixes the measurement of the width and height of the TextView space available for the text  If we don t take the drawable size into account  it is ignored and the text will end up overlapping the drawable     Updated segment adjustTextSize String    private void adjustTextSize final String text      if   mInitialized        return        int heightLimit   getMeasuredHeight   - getCompoundPaddingBottom   - getCompoundPaddingTop      mWidthLimit   getMeasuredWidth   - getCompoundPaddingLeft   - getCompoundPaddingRight       mAvailableSpaceRect right   mWidthLimit    mAvailableSpaceRect bottom   heightLimit     int maxTextSplits   text split      length    AutoResizeTextView super setMaxLines Math min maxTextSplits  mMaxLines       super setTextSize        TypedValue COMPLEX UNIT PX        binarySearch  int  mMinTextSize   int  mMaxTextSize                     mSizeTester  mAvailableSpaceRect

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Warning  bug in Android nbsp 3  Honeycomb  and Android nbsp 4 0  Ice Cream Sandwich   Androids versions  3 1 - 4 04 have a bug  that setTextSize   inside of TextView works only for the first time  first invocation    The bug is described in Issue 22493  TextView height bug in Android 4 0 and Issue 17343  button s height and text does not return to its original state after increase and decrease the text size on HoneyComb   The workaround is to add a newline character to text assigned to TextView before changing size   final String DOUBLE BYTE SPACE     u3000   textView append DOUBLE BYTE SPACE     I use it in my code as follow   final String DOUBLE BYTE SPACE     u3000   AutoResizeTextView textView    AutoResizeTextView  view findViewById R id aTextView   String fixString       if  android os Build VERSION SDK INT  gt   android os Build VERSION CODES HONEYCOMB MR1     amp  amp  android os Build VERSION SDK INT  lt   android os Build VERSION CODES ICE CREAM SANDWICH MR1          fixString   DOUBLE BYTE SPACE    textView setText fixString    The text    fixString     I add this   u3000  character on left and right of my text  to keep it centered  If you have it aligned to left then append to the right only  Of course it can be also embedded with AutoResizeTextView widget  but I wanted to keep fix code outside

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Since Android O  it s possible to auto resize text in xml   https   developer android com preview features autosizing-textview html     lt TextView     android layout width  wrap content      android layout height  wrap content      app autoSizeTextType  uniform      app autoSizeMinTextSize  12sp      app autoSizeMaxTextSize  100sp      app autoSizeStepGranularity  2sp      gt       Android O allows you to instruct a TextView to let the text size   expand or contract automatically to fill its layout based on the   TextView s characteristics and boundaries  This setting makes it   easier to optimize the text size on different screens with dynamic   content       The Support Library 26 0 Beta provides full support to the autosizing   TextView feature on devices running Android versions prior to Android   O  The library provides support to Android 4 0  API level 14  and   higher  The android support v4 widget package contains the   TextViewCompat class to access features in a backward-compatible   fashion

[android] Auto-fit TextView for Android

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