当点击icon图标进入应用时首先会调用
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
- (void)applicationDidBecomeActive:(UIApplication *)application
当点击home键进入后台
- (void)applicationWillResignActive:(UIApplication *)application
- (void)applicationDidEnterBackground:(UIApplication *)application
点击图标重新进入应用
- (void)applicationWillEnterForeground:(UIApplication *)application
- (void)applicationDidBecomeActive:(UIApplication *)application
双击home键
- (void)applicationWillResignActive:(UIApplication *)application
再点击home键
- (void)applicationDidBecomeActive:(UIApplication *)application
在前台双击home键,退出应用
- (void)applicationWillResignActive:(UIApplication *)application
- (void)applicationDidEnterBackground:(UIApplication *)application
- (void)applicationWillTerminate:(UIApplication *)application
在后台 双击home键,退出应用不会接受消息