UIViewPropertyAnimator 根据平移方向动画移动

Question

大家好，我正在尝试让我的动画根据用户平移的方式向任意一侧移动，但它不起作用，我也不知道出了什么问题。当我只使用一个方向时，手势工作正常，但当我将逻辑移至 moveLabel() 函数时，它不再工作。动画甚至没有开始。我的目标是制作相同的动画（因为我会向它添加更多细节），但让这个特定标签根据平移方向向左或向右移动。这是我现在的感冒

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var labelDummy: UILabel!

    var labelAnimation = UIViewPropertyAnimator()

    override func viewDidLoad() {
        super.viewDidLoad()

        labelDummy.center.x = view.bounds.maxX/2

        view.addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(self.moveLabel)))

    }


    func moveLabel(gesture: UIPanGestureRecognizer){

        let trans = gesture.translation(in: view)

        if trans.x >= 0{
            labelAnimation = UIViewPropertyAnimator(duration: 1.0, curve: .easeInOut) {

                let yPos = self.labelDummy.center.y
                self.labelDummy.center = CGPoint(x: 100 + (self.labelDummy.frame.size.width/2), y: yPos)
            }
        }

        if trans.x < 0 {
            labelAnimation = UIViewPropertyAnimator(duration: 1.0, curve: .easeInOut) {

                let yPos = self.labelDummy.center.y
                self.labelDummy.center = CGPoint(x: 10 + (self.labelDummy.frame.size.width/2), y: yPos)
            }
        }

        labelAnimation.fractionComplete = abs((trans.x/100))


        if gesture.state == .ended{

            labelAnimation.fractionComplete = 0
        }

        print("fractionCompleted: ", labelAnimation.fractionComplete)
    }
}

我该如何解决这个问题？

有效的代码：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var labelDummy: UILabel!

var labelAnimation = UIViewPropertyAnimator()

override func viewDidLoad() {
    super.viewDidLoad()


    labelDummy.center.x = view.bounds.maxX/2

    // Pan for hele viewen som spiller label animasjon

    view.addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(self.moveLabel)))

    // animasjon

    labelAnimation = UIViewPropertyAnimator(duration: 1.0, curve: .easeInOut) {

        let yPos = self.labelDummy.center.y
        self.labelDummy.center = CGPoint(x: 10 + (self.labelDummy.frame.size.width/2), y: yPos)
    }

    //labelAnimation.startAnimation()
}

func moveLabel(gesture: UIPanGestureRecognizer){

    print("retning: ", gesture.velocity(in: view).x)
    let trans = gesture.translation(in: view)
    print("trans: ", trans)

    labelAnimation.fractionComplete = trans.x/100
    print("fractionCompletet prøver å settes til : ", trans.x/100)
    print(trans.x)

    if gesture.state == .ended{
        print("-ENDED-")
        labelAnimation.fractionComplete = 0
    }

    print("fractionCompletet: ", labelAnimation.fractionComplete)
}

}

Answer 1

最终为 x 位置创建了一个全局变量，在 moveLabel 函数中我使用了类似 "if .began " 的 if 语句，然后检查翻译。根据翻译是高于还是低于 0，将 xposition 设置在左侧某处，或者设置在右侧某处。

if gesture.state == .began {

        if gesture.velocity(in: view).x > 0{

            // Panning right, Animate Left
            self.animationDirection = .left
            self.animateToXPos = CGPoint(x: headerLabelPositionLeft!, y: headerLabelPositionY!)
            self.setAnimation(direction: AnimationDirection.left)
            self.dayLabel.textAlignment = .left

        } else {

            // Panning left, Animate Right
            self.animationDirection = AnimationDirection.right
            self.animateToXPos = CGPoint(x: self.view.bounds.width - (self.dayLabel.frame.size.width/2), y: headerLabelPositionY)
            self.setAnimation(direction: AnimationDirection.right)
            self.dayLabel.textAlignment = .right
        }
    }

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