Adding Animated Elements to Buttons

When working with buttons, you can creatively layer art in front of or behind them. Use the standard UIView hierarchy to do this, making sure to disable user interaction for any view that might otherwise obscure your button (setUserInteractionEnabled:NO). Figure 9-7 shows what happens when you combine semitranslucent button art with an animated UIImageView behind it. The image view contents “leak” through to the viewer, enabling you to add live animation elements to the button.

Figure 9-7. Combine semitranslucent button art with animated UIImageViews to build eye-catching UI elements. In this concept, the butterfly flaps “within” the button.