longPress 时启用 UIPanGestureRecognizer

Question

当customView 执行longPress 时，我想在customView 上启用UIPanGestureRecognizer。
（我希望当你longPresscustomView时，customView会切换到“移动模式”，你可以通过拖动来移动customView。）

但在这段代码中，只有longPressAction: 被调用。 panAction: 没有打电话。
如何修复它以启用PanAction:？

- (void)viewDidLoad
{
    [self.view addSubview:customView];

    UILongPressGestureRecognizer *longPressRecognizer = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPressAction:)];
    [customView addGestureRecognizer:longPressRecognizer];
    UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panAction:)];
    [customView addGestureRecognizer:panRecognizer];
}

- (void)longPressAction:(UILongPressGestureRecognizer *)recognizer
{
    if ([recognizer state] == UIGestureRecognizerStateBegan) {
        CustomView *customView = (CustomView *)recognizer.view;
        customView.panRecongnizerEnabled = YES; //panRecongnizerEnabled is CustomView's property
    }
    if ([recognizer state] == UIGestureRecognizerStateEnded) {
        CustomView *customView = (CustomView *)recognizer.view;
        customView.panRecongnizerEnabled = NO;
    }
}

- (void)panAction:(UIPanGestureRecognizer *)recognizer
{
    CustomView *customView = (CustomView *)recognizer.view;
    if (customCell.panRecongnizerEnabled == NO) return;
    NSLog(@"running panAction");
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

Answer 1

您的 ViewController 需要符合 UIGestureRecognizerDelegate。我怀疑你要么已经这样做了 要么 否则 shouldRecognizeSimultaneouslyWithGestureRecognizer 将没有任何意义。但是您绝对缺少的是将gestureRecognizer 的委托设置为您的视图控制器：

longPressRecognizer.delegate = self;
panRecognizer.delegate = self;

现在您应该同时收到长按和平移。

注意： 我在没有任何 customView 的情况下进行了测试，只是将它们添加到 self.view。至少在这种情况下，上面的代码按预期工作。

Answer 2

我知道这个问题已经关闭了一段时间，但我最近不得不做类似的事情，并且有一个更清洁的解决方案。 UILongPressGestureRecognizer 是您执行此操作所需的全部内容。

长按手势是连续的。手势开始 (UIGestureRecognizerStateBegan) 当允许的手指数 (numberOfTouchesRequired) 已按指定时间段 (minimumPressDuration) 并且触摸不会超出 允许的移动范围（allowableMovement）。手势 每当手指移动时，识别器都会转换到 Change 状态， 并且它在任何手指时结束（UIGestureRecognizerStateEnded） 被提升了。

因此，对于您所需要的，不需要UIPanGestureRecognizer。只需添加 UILongPressGestureRecognizer 并将其附加到您的主视图。

- (void)viewDidLoad {
    [super viewDidLoad];

    UILongPressGestureRecognizer *longPressRecognizer = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPressAction:)];
    // set this to your desired delay before the pan action will start.
    longPressRecognizer.minimumPressDuration = 0.5; 
    [self.view addGestureRecognizer:longPressRecognizer];
}

然后，实现 longPressAction 方法，不仅查看UIGestureRecognizerStateBegan 或UIGestureRecognizerStateEnded 状态，还查看UIGestureRecognizerStateChanged 状态：

- (void)longPressAction:(UIGestureRecognizer *)recognizer
{
    if ([recognizer state] == UIGestureRecognizerStateBegan || [recognizer state] == UIGestureRecognizerStateChanged ) {
        CGPoint touchPoint =  [recognizer locationInView:self.view];
        [self.viewToMove setCenter: touchPoint];
        NSLog(@"running panAction");
    }
}

在我的示例中，我只是移动了一个虚拟视图来跟踪用户手指的中心，但是您可以将任何您可以放入 UIPanGestureRecognizer 的代码中的逻辑。只需将它放在 if 块中，它就会大大简化您的代码，并且您不需要处理两个手势识别器之间的交互。当用户只是在屏幕上移动手指（但没有长按）时，您的代码还会导致对 panAction 方法的许多不必要的调用。

Answer 3

您可以通过在长按后启用平移来做到这一点。无论如何，您必须保存一个标志才能知道是否调用了 longPress。为了在长按后启用平移手势，您可以使用平移手势委托，如下所示：

let previewLongPress = UILongPressGestureRecognizer(target: self, action: #selector(onLongPressed(sender:)))
let previewPanGesture = UIPanGestureRecognizer(target: self, action: #selector(onPanGesture(sender:)))

previewPanGesture?.delegate = self

你的委托应该是这样的：

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return gestureRecognizer == previewPanGesture && otherGestureRecognizer == previewLongPress
}

现在您可以在长按手势后进行平移手势。

希望它可以帮助其他人。