Question

I’m trying to draw some addition to my ImageView‘s content, which is represented by Drawable from resources. I know that all Drawables from resources are immutable by default, but even after I call mutable() method and get Bitmap from this Drawable to pass it to Canvas object I get java.lang.IllegalStateException: Immutable bitmap passed to Canvas constructor. Here is the code:

Drawable homeImage = mHomeImage.getBackground(); // my ImageView
homeImage.mutate();
Canvas c = new Canvas(((BitmapDrawable)homeImage).getBitmap());

Is there any way to modify this Bitmap without creating it’s copy?

Answer 1

Try this

Bitmap bmp1 = (((BitmapDrawable)homeImage).getBitmap())
        .copy(Config.ARGB_8888, true);
Canvas c = new Canvas(bmp1);

You will need to create a new bitmap for the canvas. As the canvas uses the bitmap we pass to store whats drawn, the bitmap should be mutable.