iOS[Swift] -- Life cycle of UIViewContorller

uiviewcontroller_lifecycle

平时在讲ViewController的生命周期时，我们只大多只关注以下六个方法：

• viewDidLoad
  *viewWillAppear
• viewDidAppear
• viewWillDisappear
• viewDidDisappear
• viewDidUnload

其实ViewController的生命周期如下：

• loadView^[1]
• viewDidLoad^[1]
• viewWillAppear
• viewWillLayoutSubviews ^[2]

  Called to notify the view controller that its view is about to layout its subviews.

• viewDidLayoutSubviews^[2]

Called to notify the view controller that its view has just laid out its subviews.

• viewDidAppear
• viewWillLayoutSubviews
• viewDidLayoutSubviews
• viewWillDisappear
• viewDidDisappear
• viewDidUnload

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1. If you manually nil out your view during didReceiveMemoryWarning, loadView and viewDidLoad will be called again. That is, by default loadView and viewDidLoad only gets called once per view controller instance. ↩ ↩

2. May be called an additional 0 or more times .viewWillLayoutSubviews and viewDidLayoutSubviews will also be called at other times when subviews of the main view are loaded, for example when cells of a table view or collection view are loaded. ↩ ↩