ios app響應background，foreground 事件實現

1 經過AppDelegate 實現

App進入後臺事件方法

- (void)applicationDidEnterBackground:(UIApplication *)application

APP進入前臺的事件方法

- (void)applicationWillEnterForeground:(UIApplication *)application

 

2UIViewController類中經過對Background ，Foreground事件的通知的偵聽，進行實現

舉例

- (void) viewWillAppear:(BOOL)animated{  

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appWillEnterForegroundNotification) name:UIApplicationWillEnterForegroundNotification object:nil];  

}  

- (void) appWillEnterForegroundNotification{  

    NSLog(@"trigger event when will enter foreground.");  

}  

-(void) viewDidDisappear:(BOOL)animated{  

    [[NSNotificationCenter defaultCenter] removeObserver:self];      

}  

注意：在UIViewController類中viewDidUnload方法在ios6之後過時失效