-(void)viewWillDisappear:(BOOL)animated

{

    [super viewWillDisappear:animated];

    //移除通知

    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"flag" object:nil];

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Do any additional setup after loading the view.

    //注册通知

    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(setMessages) name:@"flag" object:nil];

}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

    //执行通知的操作

    [[NSNotificationCenter defaultCenter]postNotificationName:@"flag" object:nil];

}

//通知所执行的操作

-(void)setMessages

{

    NSLog(@"---------I--love---you!!!---------");

}