iOS 監聽 Home鍵和從新進入程序

//監聽是否觸發home鍵掛起程序.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillResignActive)                                               name:UIApplicationWillResignActiveNotification object:nil];

//監聽是否從新進入程序程序.

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidBecomeActive)                                                name:UIApplicationDidBecomeActiveNotification object:nil];