UITapGestureRecognizer *atap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(atapAction)];
    [self.view addGestureRecognizer:atap];
    
    UITapGestureRecognizer *doubleClick = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleClickAction)];
    doubleClick.numberOfTapsRequired = 2;
    [self.view addGestureRecognizer:doubleClick];
    
    //當系統檢測不到雙擊手勢時執行再識別單擊手勢
    [atap requireGestureRecognizerToFail:doubleClick];