IOS Dev (39) Do you understand UIApplicationDelegate?

IOS Dev (39) Do you understand UIApplicationDelegate?

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• application:didFinishLaunchingWithOptions:applicationWillResignActive:applicationDidBecomeActive:applicationWillEnterBackground:applicationWillEnterForeground:applicationDidReceiveMemoryWarning:

  Application: didfinishlaunchingwitexceptions

  This is the first protocol method triggered after the UIApplication is instantiated. The main task of this product is to create a UIWindow where the Controller view is displayed.

  ApplicationWillResignActive:

  This Protocol method is triggered when the application changes from Active to Inactive. For example, when a call is made.

  ApplicationDidBecomeActive

  This Protocol method is triggered when the application changes from Inactive to Active.

  ApplicationWillEnterBackground:

  This Protocol method is triggered when the application switches to the background.

  ApplicationWillEnterForeground:

  This Protocol method is triggered when the application switches to the foreground.

  ApplicationDidReceiveMemoryWarning:

  This Protocol is triggered when the device memory is insufficient. Here I have a question: is it triggered when Background is used?

  If the system still does not have enough memory after the application executes this method, the system may kill the application.

  What if I want to actively obtain AppDelegate?

  [[UIApplication sharedApplication] delegate]

  Haha, that's easy.

  Reprinted please indicate the blog from laruence: http://blog.csdn.net/prevention