How to draw an overlay on a SurfaceView used by Camera on Android

Question

I have a simple program that draws the preview of the Camera into a SurfaceView  What I m trying to do is using the onPreviewFrame method  which is invoked each time a new frame is drawn into the SurfaceView  in order to execute the invalidate method which is supposed to invoke the onDraw method  In fact  the onDraw method is being invoked  but nothing there is being printed  I guess the camera preview is overwriting the text I m trying to draw    This is a simplify version of the SurfaceView subclass I have   public class Superficie extends SurfaceView implements SurfaceHolder Callback    SurfaceHolder mHolder   public Camera camera   Superficie Context context      super context     mHolder   getHolder      mHolder addCallback this     mHolder setType SurfaceHolder SURFACE TYPE PUSH BUFFERS       public void surfaceCreated final SurfaceHolder holder      camera   Camera open      try      camera setPreviewDisplay holder      camera setPreviewCallback new PreviewCallback         public void onPreviewFrame byte   data  Camera arg1         invalidar                     catch  IOException e         public void invalidar      invalidate        public void surfaceChanged SurfaceHolder holder  int format  int w  int h      Camera Parameters parameters   camera getParameters      parameters setPreviewSize w  h     camera setParameters parameters     camera startPreview         Override  public void draw Canvas canvas      super draw canvas        nothing gets drawn      Paint p   new Paint Color RED     canvas drawText  PREVIEW   canvas getWidth     2      canvas getHeight     2  p

User · Accepted Answer

SurfaceView probably does not work like a regular View in this regard   Instead  do the following    Put your SurfaceView inside of a FrameLayout or RelativeLayout in your layout XML file  since both of those allow stacking of widgets on the Z-axis Move your drawing logic into a separate custom View class Add an instance of the custom View class to the layout XML file as a child of the FrameLayout or RelativeLayout  but have it appear after the SurfaceView   This will cause your custom View class to appear to float above the SurfaceView   See here for a sample project that layers popup panels above a SurfaceView used for video playback

User · Answer

Try calling setWillNotDraw false  from surfaceCreated   public void surfaceCreated SurfaceHolder holder        try           setWillNotDraw false            mycam setPreviewDisplay holder           mycam startPreview          catch  Exception e            e printStackTrace            Log d TAG  Surface not created              Override protected void onDraw Canvas canvas         canvas drawRect area  rectanglePaint       Log w this getClass   getName     On Draw Called        and calling invalidate from onTouchEvent   public boolean onTouch View v  MotionEvent event         invalidate        return true

User · Answer

I think you should call the super draw   method first before you do anything in surfaceView s draw method

[android] How to draw an overlay on a SurfaceView used by Camera on Android?

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