Question

I have a button that is a nine-patch image. I do not want to provide another image for “pressed” state (that is what StateListDrawable requires). I just want it to become “darker” when it is pressed (like iOS buttons do). How can I achieve this?

Answer 1

Use something like this:

public class MyStateDrawable extends LayerDrawable {

    public MyStateDrawable(Drawable[] layers) {
        super(layers);
    }

    @Override
    protected boolean onStateChange(int[] states) {
        for (int state : states) {
            if (state == R.attr.state_activated || state == android.R.attr.state_pressed) {
                super.setColorFilter(0x7f000000, Mode.SRC_ATOP);
                return true;
            } else if(state == -android.R.attr.state_activated || state == -android.R.attr.state_pressed){
                super.setColorFilter(0x00000000, Mode.SRC_ATOP);
                return true;
            }else {
                super.setColorFilter(null);
            }
        }
        return super.onStateChange(states);
    }

    @Override
    public boolean isStateful() {
        return true;
    }
}

And then

StateDrawable state = new MyStateDrawable(new Drawable[]{mDefaultDrawable});
view.setImageDrawable(state);

Hope this will help you 🙂