Application Activate and Deactivate

When waking up i.e. relaunching an app (either through springboard, app switching or URL)applicationWillEnterForeground: is called. It is only executed once when the app becomes ready for use, after being put into the background, while applicationDidBecomeActive: may be called multiple times after launch. This makes applicationWillEnterForeground: ideal for setup that needs to occur just once after relaunch.

applicationWillEnterForeground: is called:

• when app is relaunched
• before applicationDidBecomeActive:

applicationDidBecomeActive: is called:

• when app is first launched after application:didFinishLaunchingWithOptions:
• after applicationWillEnterForeground: if there's no URL to handle.
• after application:handleOpenURL: is called.
• after applicationWillResignActive: if user ignores interruption like a phone call or SMS.

applicationWillResignActive: is called:

• when there is an interruption like a phone call.
  • if user takes call applicationDidEnterBackground: is called.
  • if user ignores call applicationDidBecomeActive: is called.
• when the home button is pressed or user switches apps.
• docs say you should
  • pause ongoing tasks
  • disable timers
  • pause a game
  • reduce OpenGL frame rates

applicationDidEnterBackground: is called:

• after applicationWillResignActive:
• docs say you should:
  • release shared resources
  • save user data
  • invalidate timers
  • save app state so you can restore it if app is terminated.
  • disable UI updates
• you have 5 seconds to do what you need to and return the method
  • if you dont return within ~5 seconds the app is terminated.
  • you can ask for more time with beginBackgroundTaskWithExpirationHandler:

1.程序启动时触发：一致

iOS4.3与iOS5.0

didFinishLaunchingWithOptions->UIApplicationStateInactive

applicationDidBecomeActive->UIApplicationStateActive

 

2.锁屏键：不同

Lock：

iOS4.3

applicationWillResignActive->UIApplicationStateActive

 

iOS5.0

applicationWillResignActive->UIApplicationStateActive

applicationDidEnterBackground->UIApplicationStateInactive

 

Unlock:

iOS4.3

applicationDidBecomeActive->UIApplicationStateActive

 

iOS5.0

applicationWillEnterForeground->UIApplicationStateInactive

applicationDidBecomeActive->UIApplicationStateActive

 

3.单击Home键：一致

进入：

iOS4.3与iOS5.0

applicationWillResignActive->UIApplicationStateActive

applicationDidEnterBackground->UIApplicationStateBackground

 

返回：

iOS4.3与iOS5.0

applicationWillEnterForeground->UIApplicationStateBackground

applicationDidBecomeActive->UIApplicationStateActive

 

4.双击Home键：一致

进入：

iOS4.3与iOS5.0

applicationWillResignActive->UIApplicationStateActive

 

返回：

iOS4.3与iOS5.0

applicationDidBecomeActive->UIApplicationStateActive

 

 

5.终结程序时：一致

iOS4.3与iOS5.0

applicationWillResignActive->UIApplicationStateActive

applicationDidEnterBackground->UIApplicationStateBackground