Question

我喜欢将UILongPressGestureRecognizer与UIPanGestureRecognizer结合使用。

UIPanGestureRecognizer应该从长按开始。有一个简单的方法吗？还是我真的要写自己的手势识别器？

我不喜欢在主屏幕上。你按下一个图标，一段时间后图标开始摇晃。之后我没有从屏幕上松开手指，我可以开始拖动手指下的图标。

Answer 1

实际上，您不必组合手势识别器 - 您只能使用UILongPressGestureRecognizer执行此操作...一旦您的触摸在'allowableMovement'中保持'minimumPressDuration'，您就进入StateBegan。只要你不抬起任何手指，你就会保持连续的longPressGesture - 所以你可以开始移动手指并通过StateChanged跟踪运动。

长按手势是连续的。当指定时间段（minimumPressDuration）按下允许的手指数（numberOfTouchesRequired）并且触摸不超出允许的移动范围（allowableMovement）时，手势开始（UIGestureRecognizerStateBegan）。每当手指移动时，手势识别器都会转换到更改状态，并且当任何手指抬起时，手势识别器会结束（UIGestureRecognizerStateEnded）。

Answer 2

我遇到这个问题有点困难。接受的答案还不够。无论我在该方法中使用什么，都会调用pan或longpress处理程序。我找到的解决方案如下：

确保将手势识别器的代理分配到同一个类（在我自己的情况下）并确保代理类为UIGestureRecognizerDelegate。

将以下委托方法添加到您的班级（根据上面的答案）：

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

将以下委托方法添加到您的班级：

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
     if([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]] && ! shouldAllowPan) {
          return NO;
     }
     return YES;
}

然后添加一个属性或ivar，它将跟踪是否应该允许平底锅开始（参见上面的方法）。就我而言BOOL shouldAllowPan。

将BOOL设置为NO或init中的viewDidLoad。在longPress处理程序中，将BOOL设置为YES。我是这样做的：

- (void) longPressHandler: (UILongPressGestureRecognizer *) gesture {

     if(UIGestureRecognizerStateBegan == gesture.state) {
        shouldAllowPan = NO;
     }

     if(UIGestureRecognizerStateChanged == gesture.state) {
        shouldAllowPan = YES;
     }
}

在panHandler中我检查BOOL：

- (void)panHandler:(UIPanGestureRecognizer *)sender{
    if(shouldAllowPan) {
          // do your stuff
    }

最后在panHandler中重置BOOL：

else if(sender.state == UIGestureRecognizerStateEnded || sender.state == UIGestureRecognizerStateFailed || sender.state == UIGestureRecognizerStateCancelled) {
    shouldAllowPan = NO;
}

然后去喝啤酒祝贺自己。 ;）

Answer 3

我找到了一个解决方案：这个UIGestureRecognizerDelegate方法完全符合我的要求：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer 
shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer

Answer 4

Andy B在Swift中的方法，

将 UIGestureRecognizerDelegate 委托添加到班级

class ViewController: UIViewController, UIGestureRecognizerDelegate

添加成员变量
```
var shouldAllowPan: Bool = false
```

添加手势，需要将平移手势委托添加到VC。这需要触发shouldRecognizeSimultaneouslyWithGestureRecognizer和gestureRecognizerShouldBegin函数

// long press
let longPressRec = UILongPressGestureRecognizer(target: self, action: "longPress:")
yourView.addGestureRecognizer(longPressRec)

// drag
let panRec = UIPanGestureRecognizer(target: self, action: "draggedView:")
panRec.delegate = self
yourView.addGestureRecognizer(panRec)

允许同步手势

func gestureRecognizer(UIGestureRecognizer,
shouldRecognizeSimultaneouslyWithGestureRecognizer:UIGestureRecognizer) -> Bool {
    // println("shouldRecognizeSimultaneouslyWithGestureRecognizer");
    return true
}

func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
     // We only allow the (drag) gesture to continue if it is within a long press
     if((gestureRecognizer is UIPanGestureRecognizer) && (shouldAllowPan == false)) {
         return false;
     }
     return true;
}

长按处理程序内部：

func longPress(sender: UILongPressGestureRecognizer) {

    if(sender.state == .Began) {
        // handle the long press
    }
    else if(sender.state == .Changed){
        shouldAllowPan = true

    }
    else if (sender.state == .Ended) {
        shouldAllowPan = false
    }
}

Answer 5

阅读Apple的UIGestureRecognizer类参考的“Subclassing Notes”部分：

https://developer.apple.com/library/prerelease/tvos/documentation/UIKit/Reference/UIGestureRecognizer_Class/

Answer 6

要组合更多手势：

创建局部变量var shouldAllowSecondGesture : Bool = false
创建两个识别器

let longPressRec = UILongPressGestureRecognizer(target: self, action: #selector(self.startDrag(sender:))) cell.addGestureRecognizer(longPressRec) let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(self.handlePan(sender:))) cell.isUserInteractionEnabled = true cell.addGestureRecognizer(panGestureRecognizer)

扩展您的VC并实现GestureRecognizerDelegate以实现此方法。

扩展YourViewController：UIGestureRecognizerDelegate {

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }



func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
         // We only allow the (drag) gesture to continue if it is within a long press
         if((gestureRecognizer is UIPanGestureRecognizer) && (shouldAllowPan == false)) {
             return false
         }
         return true
    }


@objc func startDrag(sender:UIPanGestureRecognizer) {

    if(sender.state == .began) {
            // handle the long press
        }
    else if(sender.state == .changed){
            shouldAllowPan = true

        }
        else if (sender.state == .ended) {
            shouldAllowPan = false
        }
    }

Answer 7

我通过实现“操作：选择器？”的所需功能解决了这个问题。 “动作：选择器？”中 UIPanGestureRecognizer 的函数UILongPressGestureRecognizer 的函数。

由于“UILongPressGestureRecognizer”没有成员“translation”，我通过保存原始触摸的位置并从实际触摸位置中提取来计算翻译。


// in target class
var initialTouchX : CGFloat
var initialTouchX : CGFloat


// in the @objc func for the UILongPressGestureRecognizer
if sender.state == .began {
   initialTouchX = sender.location(in: sender.view).x
   initialTouchY = sender.location(in: sender.view).y
}

let translation = CGVector(dx: sender.location(in: sender.view).x - initialTouchX, dy: sender.location(in: sender.view).y - initialTouchY)

将UILongPressGestureRecognizer与UIPanGestureRecognizer组合在一起

7 个答案: