- View确实加载
[ViewController viewDidLoad] - View将要出现
[ViewController viewWillAppear:] - View 将要布局子控件
[ViewController viewWillLayoutSubviews] - View 布局子控件完成
[ViewController viewDidLayoutSubviews] - View 确实消失
[ViewController viewDidAppear:] - View 将要消失
[ViewController viewWillDisappear:]
