【代碼筆記】iOS-NSNotificationCenter

代碼：

-(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.
    
    //註冊通知
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(setMessages) name:@"flag" object:nil];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    //執行通知的操作
    [[NSNotificationCenter defaultCenter]postNotificationName:@"flag" object:nil];
    
}
//通知所執行的操作
-(void)setMessages
{
    NSLog(@"---------I--love---you!!!---------");
}