將ImageView變成灰色竟是如此簡單

 ColorMatrix matrix = new ColorMatrix();
    matrix.setSaturation(0);
 
    ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrix);
    imageview.setColorFilter(filter);

另外PorterDuffColorFilter filter = new PorterDuffColorFilter(Color.GRAY, Mode.MULTIPLY);可以實現一些算數運算。