How to apply a color filter to a view with all children

Question

How do I grey out a view uniformly which contains many different items - ImageViews, TextViews, background image. Do I have to grey out each thing individually? Or is there

Answer 1

It's easy to do that by defining a custom view group as follows:

public class MyViewContainer extends XXXLayout {
    //XXLayout could be LinearLayout, RelativeLayout or others
    private Paint m_paint;

    //define constructors here and call _Init() at the end of constructor function

    private void
    _Init()
    {
        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0);
        m_paint = new Paint();
        m_paint.setColorFilter(new ColorMatrixColorFilter(cm));
    }

    @Override protected void 
    dispatchDraw(Canvas canvas)
    {
        canvas.saveLayer(null, m_paint, Canvas.ALL_SAVE_FLAG);
        super.dispatchDraw(canvas);
        canvas.restore();
    }
}

All children views of MyViewContainer will be shown in grey. :-)