iOS系统消息

1、键盘
一、UIKeyboardWillShowNotification-将要弹出键盘
二、UIKeyboardDidShowNotification-显示键盘
三、UIKeyboardWillHideNotification-将要隐藏键盘
四、UIKeyboardDidHideNotification-键盘已经隐藏
五、UIKeyboardWillChangeFrameNotification-键盘将要改变frame
六、UIKeyboardDidChangeFrameNotification-键盘已经改变frame

2、窗口
一、UIWindowDidBecomeVisibleNotification-窗口可见
二、UIWindowDidBecomeHiddenNotification-窗口隐藏
三、UIWindowDidBecomeKeyNotification
四、UIWindowDidResignKeyNotification
3、程序消息
一、UIApplicationDidBecomeActiveNotification-程序从后台激活
二、UIApplicationDidChangeStatusBarFrameNotification-状态栏frame改变
三、UIApplicationDidChangeStatusBarOrientationNotification-状态栏方向改变
四、UIApplicationDidEnterBackgroundNotification-进入后台
五、UIApplicationDidFinishLaunchingNotification-程序加载完成
六、UIApplicationDidReceiveMemoryWarningNotification-内存警告
七、UIApplicationProtectedDataDidBecomeAvailable
八、UIApplicationProtectedDataWillBecomeUnavailable
九、UIApplicationSignificantTimeChangeNotification 重要的时间变化（新的一天开始或时区变化）
十、UIApplicationWillChangeStatusBarOrientationNotification-将要改变状态栏方向
十一、UIApplicationWillChangeStatusBarFrameNotification-将要改变状态栏frame
十二、UIApplicationWillEnterForegroundNotification
1三、UIApplicationWillResignActiveNotification
1四、UIApplicationWillTerminateNotification

4、电池、方向、传感器
一、UIDeviceBatteryLevelDidChangeNotification //电池电量
二、UIDeviceBatteryStateDidChangeNotification //电池状态
三、UIDeviceOrientationDidChangeNotification //方向
四、UIDeviceProximityStateDidChangeNotification //近距离传感器

5、音视频
一、MPMediaLibraryDidChangeNotification
二、MPMusicPlayerControllerPlaybackStateDidChangeNotification
三、MPMusicPlayerControllerNowPlayingItemDidChangeNotification
四、MPMusicPlayerControllerVolumeDidChangeNotification

6、其余 
一、NSUserDefaultsDidChangeNotification 用户默认设置变化
2   NSCurrentLocaleDidChangeNotification 本地化语言变化