UIButton object is • Native iOS SDK interface components. • Optimized for touch interactions. • Interaction elements that are familiar to every iPhone/iPad user. • Can be extended and enhanced.
the view controller gets: • Instantiated/loaded (viewDidLoad) • Before it appears (viewWillAppear) • After it appears (viewDidAppear) • Before it disappears (viewWillDisappear) • After it disappears (viewDidDisappear) • After its unloaded (viewDidUnload)