Android : Android Photo Background Eraser need help- Not erasing bitmap but just draws black lines

I am developing 1 app in that i need to erase the Bitmap for that i have done is

@Override
        protected void onDraw(Canvas canvas) {

            canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
            for (PathPoints p : paths) {
                mPaint.setColor(p.getColor());
                mPaint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
                Log.v("", "Color code : " + p.getColor());
                if (p.isTextToDraw()) {
                    canvas.drawText(p.textToDraw, p.x, p.y, mPaint);
                } else {
                    canvas.drawPath(p.getPath(), mPaint);
                }
            }

But the above code only draws the black lines on Bitmap I have Seen this link But not getting Actually I want it LIKE THIS