viewDidLoad， viewWillDisappear， viewWillAppear等差别

躯体老是以惹人腻烦了却。除思惟以外，没有什么精美和有意思的器材留下来，因为思惟就是生命。viewWillAppear:?
Called when the view is about to made visible. Default does nothing
视图即将可见时调用。默认景象下不履行任何操纵
viewDidAppear:?
Called when the view has been fully transitioned onto the screen. Default does nothing
视图已完全过渡到屏幕上时调用
viewWillDisappear:
Called when the view is dismissed， covered or otherwise hidden. Default does nothing
视图被驳回时调用，覆盖或以其他体式格式隐蔽。默认景象下不履行任何操纵
viewDidDisappear:
Called after the view was dismissed， covered or otherwise hidden. Default does nothing
视图被驳回后调用，覆盖或以其他体式格式隐蔽。默认景象下不履行任何操纵

loadView;?
This is where subclasses should create their custom view hierarchy if they aren""t using a nib. Should never be called directly.
这是当他们没有正在应用nib视图页面，子类将会创建本身的自定义视图层。毫不克不及直接调用。
viewDidLoad;
Called after the view has been loaded. For view controllers created in code， this is after -loadView. For view controllers unarchived a nib， this is after the view is set.
在视图加载后被调用，若是是在代码中创建的视图加载器，他将会在loadView办法后被调用，若是是从nib视图页面输出，他将会在视图设置好后后被调用