Android Canvas Clear With Transparency


Answer :

Use the following.

 canvas.drawColor(Color.TRANSPARENT,Mode.CLEAR);

The solution was to create a secondary canvas and bitmap to draw on. My Custom View's onSizeChanged() method looked like

@Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {     super.onSizeChanged(w, h, oldw, oldh);      bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);     bitmap.eraseColor(Color.TRANSPARENT);     temp = new Canvas(bitmap); }

and the onDrawMethod looks like

@Override protected void onDraw(Canvas canvas) {     super.onDraw(canvas);      temp.drawColor(Color.argb(80, 0, 0, 0));     temp.drawCircle(centerPosX, centerPosY, 200, transparentPaint);     canvas.drawBitmap(bitmap, 0, 0, null); }

where transparentPaint is declared in the onstructor as 

transparentPaint = new Paint(); transparentPaint.setColor(getResources().getColor(android.R.color.transparent)); transparentPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR)); transparentPaint.setAntiAlias(true);

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