ScrollView 平移手势和 panGestureRecognizer 冲突

Question

我在UIViewController 中有一个UIScrollView，它通过segue 模态显示，另外一个UIPanGestureRecognizer 通过平移关闭视图控制器。此手势仅在

时有效

 scrollView.contentOffset.y == 0

问题是，现在两个平移手势相互冲突，我无法再滚动视图。

为了解决这个问题，我尝试使用gestureRecognizer(_: shouldRecognizeSimultaneouslyWith:) 方法，返回是，并且我尝试将自定义平移手势添加到UIScrollView 平移手势识别器，如下所示：

 scrollView.panGestureRecognizer.addTarget(self, action: #selector(handlePanGesture(_:)))

但这些并不能解决问题 如果您知道如何解决此问题，我将不胜感激。

已编辑

以下是我的平移手势关闭视图控制器的代码：

     @IBAction func handlePanGesture(_ sender: UIPanGestureRecognizer) {
    let percentThreshold: CGFloat = 0.3

    if scrollView.contentOffset.y == 0 {
        let translation = sender.translation(in: view)
        let verticalMovement = translation.y / view.bounds.height
        let downwardMovement = fmaxf(Float(verticalMovement), 0.0)
        let downwardMovementPercent = fminf(downwardMovement, 1.0)
        let progress = CGFloat(downwardMovementPercent)

        guard let interactor = interactor else {return}
        switch sender.state {
        case .began:
            interactor.hasStarted = true
            dismiss(animated: true, completion: nil)
        case .changed:
            interactor.shouldFinish = progress > percentThreshold
            interactor.update(progress)
        case .cancelled:
            interactor.hasStarted = false
            interactor.cancel()
        case .ended:
            interactor.hasStarted = false
            interactor.shouldFinish ? interactor.finish() : interactor.cancel()
        default:
            break
        }

    }
}

EDITED_2 这是Interactor的代码：

class Interactor: UIPercentDrivenInteractiveTransition {
var hasStarted = false
var shouldFinish = false 

}

附：我知道有很多类似的问题，但它们对我不起作用。

Answer 1

要在 UIPanGestureRecognizer 位于 ScrollView 上时允许滚动，您需要创建一个在 gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:) 上返回 true 的 UIGestureRecognizerDelegate

如果您不这样做，则 ScrollView 上将无法滚动。

这样做是这样的：

let scrollViewPanGesture = UIPanGestureRecognizer(target: self, action: #selector(onPan(_:)))
scrollViewPanGesture.delegate = self
scrollView.addGestureRecognizer(scrollViewPanGesture)

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

Answer 2

我不确定，但您可以尝试将ViewController 添加为滑动的UIPanGestureRecognizer 代表以关闭平移手势并实现gestureRecognizerShouldBegin(_:)；

func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    return scrollView.contentOffset.y == 0
}

所以只有当内容偏移量为零时才会开始关闭手势。

Answer 3

在滚动视图下添加一个子视图并将平移手势添加到它而不是将其添加到 self.view 肯定会与滚动视图的冲突

Answer 4

你在实施时做对了gestureRecognizer(_: shouldRecognizeSimultaneouslyWith:)
但是您必须先将手势委托设置为当前的 View Controller：

let panGesture = UIPanGestureRecognizer.init(target: self, action: #selector(handlePanGesture(_:)))
panGesture.delegate = self // <--THIS
scrollView.addGestureRecognizer(panGesture)