使用 panGesture 的交互式动画 iOS

Question

我有一个 sheetView，其上边缘始终居中于父视图中心。

我允许它使用平移手势垂直拖动，当手势结束时，我正在将 sheetView 动画化回父视图的中心。

但是我想在 sheetView 还在动画的时候与它交互，在平移的时候垂直改变它的位置，但是我做不到，它总是完成当前动画然后开始下一个动画。

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    sheetView.frame = CGRect(x: 0, y: 0, width: view.bounds.width, height: view.bounds.height)
    middlePoint = CGPoint(x: view.bounds.midX, y: view.bounds.height)
    sheetView.center = middlePoint
}

@IBAction func handlePan(_ sender: UIPanGestureRecognizer) {
    let recognizer = sender
    let translation = recognizer.translation(in: self.view)

    if recognizer.state == .began {
        if animator.isRunning {
            animator.stopAnimation(true)
        }
        animator.addAnimations {
            self.sheetView.center = self.middlePoint
        }
        animator.pauseAnimation()
    } else if recognizer.state == .changed {
        self.sheetView.center.y += translation.y

    } else if recognizer.state == .ended || recognizer.state == .cancelled {
        if animator.isRunning {
            animator.stopAnimation(true)
        }
        animator.addAnimations {
            self.sheetView.center = self.middlePoint
        }
        animator.startAnimation()
    }

    recognizer.setTranslation(CGPoint.zero, in: self.view)
}

您可以在这里找到整个项目：sheetView

Answer 1

@objc func panGestureAction(_ gestureRecognizer: UIPanGestureRecognizer) {

    guard gestureRecognizer.view != nil else {return}

    let directionVelocity = gestureRecognizer.velocity(in: myView)

    switch gestureRecognizer.state {

    case .changed:

        if directionVelocity.x > 0 {

            //print("swipe right")
        }

        if directionVelocity.x < 0 {

            //print("swipe left")
        }

        if directionVelocity.y > 0 {

            //print("swipe down")

        }

        if directionVelocity.y < 0 {

            //print("swipe up")

        }
        break

    case .ended :

       //print(“Ended”)  

    default:
        break
    }

}

希望对你有所帮助

Answer 2

因为你一直在应用动画。即使您正在移动视图，这也不是必需的。当您移动视图时，该动画会导致中断。

    @IBAction func handlePan(_ sender: UIPanGestureRecognizer) {
        let recognizer = sender
        let translation = recognizer.translation(in: self.view)

        if recognizer.state == .began{
                self.sheetView.center = self.middlePoint
        } else if recognizer.state == .changed{
            self.sheetView.center.y += translation.y

        }else if recognizer.state == .ended || recognizer.state == .cancelled{
            if animator.isRunning{
                animator.stopAnimation(true)
            }
            animator.addAnimations {
                self.sheetView.center = self.middlePoint
            }
            animator.startAnimation()
        }

        recognizer.setTranslation(CGPoint.zero, in: self.view)

    }

使用 panGesture 的交互式动画 iOS

interactive animation with panGesture iOS

core-animation

ios

swift

uiviewpropertyanimator