UISwipeGestureRecognizerDirection问题

Question

在viewDidLoad 中设置：

 UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [swipeGesture setDirection:(UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight)];
    [self.view addGestureRecognizer:swipeGesture];

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
    NSLog(@"Swipe received.");
    UISwipeGestureRecognizerDirection temp = recognizer.direction;
    if (recognizer.direction == UISwipeGestureRecognizerDirectionLeft)
    {
        [self backCalendarPressed:nil];
    }
    else if (recognizer.direction == UISwipeGestureRecognizerDirectionRight)
    {
        [self nextCalendarPressed:nil];
    }
}

但是recognizer.direction总是等于3，这样的结果我没有办法判断是向左滑动还是向右滑动。

Answer 1

在初始时设置确定一个初始状态.比如下一步的动作是向左滑. 设置direction

 [swipeGesture setDirection:UISwipeGestureRecognizerDirectionLeft]; 

只添加对向左滑的手势支持,而不是两个方向的支持.可加一个BOOL类型的变量来标识当前的滑动方向

BOOL isLeft=NO;

在处理滑动的事件处理中,根据当前方向重置direction

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
    NSLog(@"Swipe received.");
    UISwipeGestureRecognizerDirection temp = recognizer.direction;
    if (!isLeft)
    {
        [swipeGesture setDirection:UISwipeGestureRecognizerDirectionRight];
        [self backCalendarPressed:nil];
    }
    else 
    {
        [swipeGesture setDirection:UISwipeGestureRecognizerDirectionLeft];
        [self nextCalendarPressed:nil];
    }
    isLeft=!isLeft;
}