Converting a view to Bitmap without displaying it in Android

Question

I will try to explain what exactly I need to do   I have 3 separate screens say A B C  There is another screen called say HomeScreen where all the 3 screens bitmap should be displayed in Gallery view and the user can select in which view does he wants to go    I have been able to get the Bitmaps of all the 3 screens and display it in Gallery view by placing all the code in HomeScreen Activity only  Now  this has complicated the code a lot and I will like to simplify it    So  can I call another Activity from HomeScreen and do not display it and just get the Bitmap of that screen  For example  say I just call HomeScreen and it calls Activity A B C and none of the Activities from A B C are displayed  It just gives the Bitmap of that screen by getDrawingCache    And then we can display those bitmaps in Gallery view in HomeScreen   I hope I have explained the problem very clearly   Please let me know if this is actually possible

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There is a great Kotlin extension function in Android KTX  View drawToBitmap Bitmap Config

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here is my solution   public static Bitmap getBitmapFromView View view        Bitmap returnedBitmap   Bitmap createBitmap view getWidth    view getHeight   Bitmap Config ARGB 8888       Canvas canvas   new Canvas returnedBitmap       Drawable bgDrawable  view getBackground        if  bgDrawable  null           bgDrawable draw canvas       else          canvas drawColor Color WHITE       view draw canvas       return returnedBitmap      Enjoy

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I know this may be a stale issue  but I was having problems getting any of these solutions to work for me  Specifically  I found that if any changes were made to the view after it was inflated that those changes would not get incorporated into the rendered bitmap   Here s the method which ended up working for my case  With one caveat  however  prior to calling getViewBitmap View  I inflated my view and asked it to layout with known dimensions  This was needed since my view layout would make it zero height width until content was placed inside   View view   LayoutInflater from context  inflate layoutID  null     Do some stuff to the view  like add an ImageView  etc  view layout 0  0  width  height    Bitmap getViewBitmap View view          Get the dimensions of the view so we can re-layout the view at its current size       and create a bitmap of the same size      int width   view getWidth        int height   view getHeight         int measuredWidth   View MeasureSpec makeMeasureSpec width  View MeasureSpec EXACTLY       int measuredHeight   View MeasureSpec makeMeasureSpec height  View MeasureSpec EXACTLY          Cause the view to re-layout     view measure measuredWidth  measuredHeight       view layout 0  0  view getMeasuredWidth    view getMeasuredHeight            Create a bitmap backed Canvas to draw the view into     Bitmap b   Bitmap createBitmap width  height  Bitmap Config ARGB 8888       Canvas c   new Canvas b          Now that the view is laid out and we have a canvas  ask the view to draw itself into the canvas     view draw c        return b      The  magic sauce  for me was found here  https   groups google com forum   topic android-developers BxIBAOeTA1Q  Cheers   Levi

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Hope this helps  View view  some view instance           view setDrawingCacheEnabled true   Bitmap bitmap view getDrawingCache    view setDrawingCacheEnabled false     Update getDrawingCache   method is deprecated in API level 28  So look for other alternative for API level   28

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there is a way to do this  you have to create a Bitmap and a Canvas and call view draw canvas    here is the code   public static Bitmap loadBitmapFromView View v        Bitmap b   Bitmap createBitmap  v getLayoutParams   width  v getLayoutParams   height  Bitmap Config ARGB 8888                       Canvas c   new Canvas b       v layout v getLeft    v getTop    v getRight    v getBottom         v draw c       return b      if the view wasn t displayed before the size of it will be zero  Its possible to measure it like this    if  v getMeasuredHeight    lt   0        v measure LayoutParams WRAP CONTENT  LayoutParams WRAP CONTENT       Bitmap b   Bitmap createBitmap v getMeasuredWidth    v getMeasuredHeight    Bitmap Config ARGB 8888       Canvas c   new Canvas b       v layout 0  0  v getMeasuredWidth    v getMeasuredHeight         v draw c       return b      EDIT  according to this post  Passing WRAP CONTENT as value to makeMeasureSpec   doesn t to do any good  although for some view classes it does work   and the recommended method is      Either this int specWidth   MeasureSpec makeMeasureSpec parentWidth  MeasureSpec AT MOST      Or this int specWidth   MeasureSpec makeMeasureSpec 0    any     MeasureSpec UNSPECIFIED   view measure specWidth  specWidth   int questionWidth   view getMeasuredWidth

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Layout or view  to bitmap    private Bitmap createBitmapFromLayout View tv              int spec   View MeasureSpec makeMeasureSpec 0  View MeasureSpec UNSPECIFIED       tv measure spec  spec       tv layout 0  0  tv getMeasuredWidth    tv getMeasuredHeight         Bitmap b   Bitmap createBitmap tv getMeasuredWidth    tv getMeasuredWidth                Bitmap Config ARGB 8888       Canvas c   new Canvas b       c translate  -tv getScrollX      -tv getScrollY          tv draw c       return b      Calling Method    Bitmap src   createBitmapFromLayout View inflate this  R layout sample  null    or pass your view object

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I think this is a bit better           draws the view s content to a bitmap  code initially based on      http   nadavfima com android-snippet-inflate-a-layout-draw-to-a-bitmap       Nullable public static Bitmap drawToBitmap final View viewToDrawFrom  int width  int height        boolean wasDrawingCacheEnabled   viewToDrawFrom isDrawingCacheEnabled        if   wasDrawingCacheEnabled          viewToDrawFrom setDrawingCacheEnabled true       if  width  lt   0    height  lt   0            if  viewToDrawFrom getWidth    lt   0    viewToDrawFrom getHeight    lt   0                viewToDrawFrom measure MeasureSpec makeMeasureSpec 0  MeasureSpec UNSPECIFIED   MeasureSpec makeMeasureSpec 0  MeasureSpec UNSPECIFIED                width   viewToDrawFrom getMeasuredWidth                height   viewToDrawFrom getMeasuredHeight                      if  width  lt   0    height  lt   0                final Bitmap bmp   viewToDrawFrom getDrawingCache                final Bitmap result   bmp    null   null   Bitmap createBitmap bmp               if   wasDrawingCacheEnabled                  viewToDrawFrom setDrawingCacheEnabled false               return result                    viewToDrawFrom layout 0  0  width  height         else           viewToDrawFrom measure MeasureSpec makeMeasureSpec width  MeasureSpec EXACTLY   MeasureSpec makeMeasureSpec height  MeasureSpec EXACTLY            viewToDrawFrom layout 0  0  viewToDrawFrom getMeasuredWidth    viewToDrawFrom getMeasuredHeight               final Bitmap drawingCache   viewToDrawFrom getDrawingCache        final Bitmap bmp   ThumbnailUtils extractThumbnail drawingCache  width  height       final Bitmap result   bmp    null    bmp    drawingCache   bmp   Bitmap createBitmap bmp       if   wasDrawingCacheEnabled          viewToDrawFrom setDrawingCacheEnabled false       return result      Using the above code  you don t have to specify the size of the bitmap  use 0 for width amp height  if you want to use the one of the view itself   Also  if you wish to convert special views  SurfaceView  Surface or Window  for example  to a bitmap  you should consider using PixelCopy class instead  It requires API 24 and above though  I don t know how to do it before

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Try this           Draw the view into a bitmap      public static Bitmap getViewBitmap View v        v clearFocus        v setPressed false        boolean willNotCache   v willNotCacheDrawing        v setWillNotCacheDrawing false           Reset the drawing cache background color to fully transparent        for the duration of this operation     int color   v getDrawingCacheBackgroundColor        v setDrawingCacheBackgroundColor 0        if  color    0            v destroyDrawingCache              v buildDrawingCache        Bitmap cacheBitmap   v getDrawingCache        if  cacheBitmap    null            Log e TAG   failed getViewBitmap     v        new RuntimeException             return null             Bitmap bitmap   Bitmap createBitmap cacheBitmap           Restore the view     v destroyDrawingCache        v setWillNotCacheDrawing willNotCache       v setDrawingCacheBackgroundColor color        return bitmap

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I used this just a few days ago  fun generateBitmapFromView view  View   Bitmap       val specWidth   View MeasureSpec makeMeasureSpec 1324  View MeasureSpec AT MOST      val specHeight   View MeasureSpec makeMeasureSpec 521  View MeasureSpec AT MOST      view measure specWidth  specHeight      val width   view measuredWidth     val height   view measuredHeight     val bitmap   Bitmap createBitmap width  height  Bitmap Config ARGB 8888      val canvas   Canvas bitmap      view layout view left  view top  view right  view bottom      view draw canvas      return bitmap    This code is based in this gist

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view setDrawingCacheEnabled true   Bitmap bitmap   Bitmap createBitmap view getDrawingCache     view setDrawingCacheEnabled false

[android] Converting a view to Bitmap without displaying it in Android?

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