Android ImageButton that automatically darkens on press, as with iOS UIButton's default highlight. The draw() method is overridden to alpha out the button if disabled. The idea is you quickly get button states without providing state list drawables.

AutoHighlightImageButton

// if you're wanting to put these inside an AdapterView, replace ImageButton below with ImageView
public class AutoHighlightImageButton extends ImageButton {
  private boolean mIsPressed;

	public AutoHighlightImageButton(Context context) {
	    super(context);
	    init();
	}   

	public AutoHighlightImageButton(Context context, AttributeSet attrs) {
	    super(context, attrs);
	    init();
	}   

	public AutoHighlightImageButton(Context context, AttributeSet attrs, int defStyle) {
	    super(context, attrs, defStyle);
	    init();
	}
	
	private void init() {
	    mIsPressed = false;
	}
	
	@Override
	public void draw(Canvas canvas) {
	  // alpha to 0.5 when disabled
	  canvas.saveLayerAlpha(null, isEnabled() ? 255 : 127, Canvas.ALL_SAVE_FLAG);
	  super.draw(canvas);
	  canvas.restore();
	}
	
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		if(isEnabled()) {
			if (event.getAction() == MotionEvent.ACTION_DOWN && !mIsPressed) {
				setColorFilter(0x99000000);
				mIsPressed = true;
				return true;
				
			} else if (event.getAction() == MotionEvent.ACTION_CANCEL || event.getAction() == MotionEvent.ACTION_UP) {
				if(mIsPressed) {
					setColorFilter(Color.TRANSPARENT);
					mIsPressed = false;
				}
			}
			
		}
	  return super.onTouchEvent(event);
	}
}