android如何在画布上绘制半透明的位图

Question

我试图修改一个Paint变量，但是一直不成功 - 我怎样才能让位图显示为“半透明”？

Answer 1

canvas.drawColor(Color.WHITE);   
BitmapDrawable bd = (BitmapDrawable) getResources().getDrawable(R.drawable.loading);    
Bitmap bm = bd.getBitmap();    
Paint paint = new Paint();    
paint.setAlpha(60);                             //you can set your transparent value here    
canvas.drawBitmap(bm, 0, 0, paint);

Answer 2

Paint p = new Paint();
p.setAlpha(70);

Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.wallpaper);
canvas.drawBitmap(image, xPosition, yPosition, p);