iOS系統消息

1、鍵盤
一、UIKeyboardWillShowNotification-將要彈出鍵盤
二、UIKeyboardDidShowNotification-顯示鍵盤
三、UIKeyboardWillHideNotification-將要隱藏鍵盤
四、UIKeyboardDidHideNotification-鍵盤已經隱藏
五、UIKeyboardWillChangeFrameNotification-鍵盤將要改變frame
六、UIKeyboardDidChangeFrameNotification-鍵盤已經改變frame

2、窗口
一、UIWindowDidBecomeVisibleNotification-窗口可見
二、UIWindowDidBecomeHiddenNotification-窗口隱藏
三、UIWindowDidBecomeKeyNotification
四、UIWindowDidResignKeyNotification
3、程序消息
一、UIApplicationDidBecomeActiveNotification-程序從後臺激活
二、UIApplicationDidChangeStatusBarFrameNotification-狀態欄frame改變
三、UIApplicationDidChangeStatusBarOrientationNotification-狀態欄方向改變
四、UIApplicationDidEnterBackgroundNotification-進入後臺
五、UIApplicationDidFinishLaunchingNotification-程序加載完成
六、UIApplicationDidReceiveMemoryWarningNotification-內存警告
七、UIApplicationProtectedDataDidBecomeAvailable
八、UIApplicationProtectedDataWillBecomeUnavailable
九、UIApplicationSignificantTimeChangeNotification 重要的時間變化（新的一天開始或時區變化）
十、UIApplicationWillChangeStatusBarOrientationNotification-將要改變狀態欄方向
十一、UIApplicationWillChangeStatusBarFrameNotification-將要改變狀態欄frame
十二、UIApplicationWillEnterForegroundNotification
1三、UIApplicationWillResignActiveNotification
1四、UIApplicationWillTerminateNotification

4、電池、方向、傳感器
一、UIDeviceBatteryLevelDidChangeNotification //電池電量
二、UIDeviceBatteryStateDidChangeNotification //電池狀態
三、UIDeviceOrientationDidChangeNotification //方向
四、UIDeviceProximityStateDidChangeNotification //近距離傳感器

5、音視頻
一、MPMediaLibraryDidChangeNotification
二、MPMusicPlayerControllerPlaybackStateDidChangeNotification
三、MPMusicPlayerControllerNowPlayingItemDidChangeNotification
四、MPMusicPlayerControllerVolumeDidChangeNotification

6、其餘 
一、NSUserDefaultsDidChangeNotification 用戶默認設置變化
2   NSCurrentLocaleDidChangeNotification 本地化語言變化