未调用 UISwipeGestureRecognizer UIGestureRecognizerStateChanged

Question

我在我的应用程序中定义了两个 UISwipeGestureRecognizer：

UISwipeGestureRecognizer *swipeLeftVolume = [[UISwipeGestureRecognizer alloc]  initWithTarget:self action:@selector(handleSwipeGestureVolume:)];
swipeLeftVolume.direction = UISwipeGestureRecognizerDirectionLeft;
[self.playerView addGestureRecognizer:swipeLeftVolume];

UISwipeGestureRecognizer *swipeRightVolume = [[UISwipeGestureRecognizer alloc]  initWithTarget:self action:@selector(handleSwipeGestureVolume:)];
swipeRightVolume.direction = UISwipeGestureRecognizerDirectionRight;
[self.playerView addGestureRecognizer:swipeRightVolume];

在目标方法中我有 3 个状态：

UIGestureRecognizerStateBegan
UIGestureRecognizerStateChanged
UIGestureRecognizerStateEnded

我注意到只有 UIGestureRecognizerStateEnded 被调用了。

知道问题出在哪里吗？我想识别特定 UIView 上的滑动：

- (void)handleSwipeGestureVolume:(UISwipeGestureRecognizer *)sender {
    if (sender.state == UIGestureRecognizerStateBegan) {
        NSLog(@"Start");
    } else if (sender.state == UIGestureRecognizerStateChanged) {
        NSLog(@"Changed");
    } else if (sender.state == UIGestureRecognizerStateEnded) {
        NSLog(@"Finish");
    }
}

Answer 1

确保为 self.playerView.

启用 UserInteraction

Answer 2

对于任何手势识别器，必须启用用户交互才能工作。没有它 none 的手势将被触发，包括 touchBegan:、touchMove: 等

所以你需要[self.playerView setUserInteractionEnabled:TRUE];

还有一件事我想让你知道，如果你实现了 touchBegan:、touchMove: 等，那么该方法将首先针对手势触发，而不是 UIGestureRecognizer 盾牌。

Answer 3

您似乎对 UISwipeGestureRecognizer 和 UIPanGestureRecognizer 感到困惑。

UISwipeGestureRecognizer 将仅生成 UIGestureRecognizerStateEnded 状态 而 UIPanGestureRecognizer 具有您想要的 3 个状态。

如果您需要同时接收 UIGestureRecognizerStateBegan、UIGestureRecognizerStateChanged、UIGestureRecognizerStateEnded，请改用 UIPanGestureRecognizer。

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc]  initWithTarget:self action:@selector(handleSwipeGestureVolume:)];
[self.playerView addGestureRecognizer:panGesture];