How to use

layout

method

in

android.view.SurfaceView

@SuppressLint("DrawAllocation")
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
  containerSized(new Size(r - l, b - t));
  if(surfaceView != null) {
    if (surfaceRect == null) {
      // Match the container, to reduce the risk of issues. The preview should never be drawn
      // while the surface has this size.
      surfaceView.layout(0, 0, getWidth(), getHeight());
    } else {
      surfaceView.layout(surfaceRect.left, surfaceRect.top, surfaceRect.right, surfaceRect.bottom);
    }
  } else if(textureView != null) {
    textureView.layout(0, 0, getWidth(), getHeight());
  }
}

 public class CroppedCameraPreview extends ViewGroup {
 private SurfaceView cameraPreview;
 public CroppedCameraPreview( Context context ) {
  super( context );
  // i'd probably create and add the SurfaceView here, but it doesn't matter
 }
 @Override
 protected void onMeasure( int widthMeasureSpec, int heightMeasureSpec ) {
  setMeasuredDimension( croppedWidth, croppedHeight );
 }
 @Override
 protected void onLayout( boolean changed, int l, int t, int r, int b ) {
  if ( cameraPreview != null ) {
   cameraPreview.layout( 0, 0, actualPreviewWidth, actualPreviewHeight );
  }
 }
}

 public class CroppedCameraPreview extends ViewGroup {
 private SurfaceView cameraPreview;
 public CroppedCameraPreview( Context context ) {
  super( context );
  // i'd probably create and add the SurfaceView here, but it doesn't matter
 }
 @Override
 protected void onMeasure( int widthMeasureSpec, int heightMeasureSpec ) {
  setMeasuredDimension( croppedWidth, croppedHeight );
 }
 @Override
 protected void onLayout( boolean changed, int l, int t, int r, int b ) {
  if ( cameraPreview != null ) {
   cameraPreview.layout( 0, 0, actualPreviewWidth, actualPreviewHeight );
  }
 }
}

 public class BarcodeCameraPreview extends ViewGroup {

private SurfaceView mSurfaceView;

public BarcodeCameraPreview(final Context context, AttributeSet attrs) {
  super(context, attrs);

  mSurfaceView = new SurfaceView(context);
  mSurfaceView.getHolder().addCallback(new SurfaceCallback());
  addView(mSurfaceView);
}

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    // crop view
    int actualPreviewWidth = getResources().getDisplayMetrics().widthPixels;
    int actualPreviewHeight = getResources().getDisplayMetrics().heightPixels;


    if (mSurfaceView != null) {
      mSurfaceView.layout(0, 0, actualPreviewWidth, actualPreviewHeight);
    }
  }

// camera methods

}

mSurfaceView.layout(0, 0, actualPreviewWidth, actualPreviewHeight);