Android - Touch To Erase Portions Of Foreground Imageview To Expose Background View

So I've been struggling with this for a better part of a day. Suppose I have a custom ImageView that I want to overlay over a background View (both within a RelativeLayout), which

Solution 1:

I know this is a really old question but here is what I did to fix a similar problem I had. Maybe it helps someone in the future.

From API level 11 and up you have to specify this piece of code for your ImageView to unveil the image in the back and not a black area.

if (Build.VERSION.SDK_INT >= 11) {
    imageview.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}

This helped me displaying the back image successfully

Solution 2:

Can you try this solution it will help you with the erasing images in android on touch .. Or download a demo example

publicclassMainActivityextendsActivity {

    Bitmap bp;
    Canvas bitmapCanvas;
    DrawView drawImg;
    LinearLayout ln1;

    @OverrideprotectedvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        ln1 = (LinearLayout) findViewById(R.id.ln1);
        drawImg = newDrawView(this);
        ln1.addView(drawImg);

    }



    publicclassDrawViewextendsViewimplementsView.OnTouchListener {

        privateintx=0;
        privateinty=0;

        Bitmap bitmap;
        Path circlePath;
        Paint circlePaint;

        privatefinalPaintpaint=newPaint();
        privatefinalPainteraserPaint=newPaint();


        publicDrawView(Context context){
            super(context);
            setFocusable(true);
            setFocusableInTouchMode(true);
            this.setOnTouchListener(this);

            // Set backgroundthis.setBackgroundColor(Color.CYAN);
            bp = BitmapFactory.decodeResource(getResources(), R.drawable.bg);

            // Set bitmap
            bitmap = Bitmap.createBitmap(320, 480, Bitmap.Config.ARGB_8888);
            bitmapCanvas = newCanvas();
            bitmapCanvas.setBitmap(bitmap);
            bitmapCanvas.drawColor(Color.TRANSPARENT);
            bitmapCanvas.drawBitmap(bp, 0, 0, null);

            circlePath = newPath();
            circlePaint = newPaint();
            circlePaint.setAntiAlias(true);
            circlePaint.setColor(Color.BLUE);
            circlePaint.setStyle(Paint.Style.STROKE);
            circlePaint.setStrokeJoin(Paint.Join.MITER);
            circlePaint.setStrokeWidth(4f);

            // Set eraser paint properties
            eraserPaint.setAlpha(0);
            eraserPaint.setStrokeJoin(Paint.Join.ROUND);
            eraserPaint.setStrokeCap(Paint.Cap.ROUND);
            eraserPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.CLEAR));
            eraserPaint.setAntiAlias(true);

        }

        @OverridepublicvoidonDraw(Canvas canvas) {

            canvas.drawBitmap(bitmap, 0, 0, paint);
            bitmapCanvas.drawCircle(x, y, 30, eraserPaint);

            canvas.drawPath(circlePath, circlePaint);
        }

        publicbooleanonTouch(View view, MotionEvent event) {
            x = (int) event.getX();
            y = (int) event.getY();

            bitmapCanvas.drawCircle(x, y, 30, eraserPaint);

            circlePath.reset();
            circlePath.addCircle(x, y, 30, Path.Direction.CW);

            int ac=event.getAction();
            switch(ac){
                case MotionEvent.ACTION_UP:
                    Toast.makeText(MainActivity.this, String.valueOf(x), Toast.LENGTH_SHORT).show();
                    circlePath.reset();
                    break;
            }
            invalidate();
            returntrue;
        }
    }
}