Swift 如何使用属性带有平移手势的动画器

Question

所以我有一个 UIView 附加了一个 PanGestureRecognizer 允许我上下移动视图。当我向上移动视图时，我想 减少按钮的 alpha，当我 向下移动视图时，我想将其增加到正常值 。

我曾尝试在按钮卡入某个位置时单独为按钮设置动画，但这会破坏我的 PropertyAnimator。

我目前的实现工作发现，前提是我的手指在视图上，因为这个 returns 来自识别器的 .changed 状态。但我也有实现，当视图在沿 y 轴 的某个点释放时，将视图捕捉到位。问题是它没有达到 .changed 状态，因此改变了我的 hideAnimator.fractionComplete 在动画中途离开按钮。

初始化属性动画师方法

func initPropertyAnimator() {

    hideAnimator = UIViewPropertyAnimator(duration: 0.18, curve: .easeInOut, animations: {
        self.requestButton.alpha = 0
    })
}

识别器状态为 panGesture(recognizer: UIPanGestureRecognizer)

let currentY = self.frame.minY

switch recognizer.state {
    case .began:
        print("Began")

    case .changed:

        // Property animator
        let offset: CGFloat = window!.frame.height-194
        let percentage: CGFloat = (offset-currentY)/100
        print(percentage)
        hideAnimator?.fractionComplete = CGFloat(percentage)

    case .ended:
        // Snap back below 80 (y)
        if currentY < 80 || currentY > 80 && currentY < halfWayPoint
        {
            self.animator?.stopAnimation(true)
            UIView.animate(withDuration:0.62, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations:
                {
                    recognizer.view!.frame = CGRect(x: 0, y: 80, width: self.frame.width, height: self.frame.height)
                    self.requestButton.alpha = 0
                    self.houseView.frame = CGRect(x: 16, y: 87, width: self.boxWidth, height: 68)
                    self.officeView.frame = CGRect(x: 16, y: 171, width: self.boxWidth, height: 68)
                    self.carView.frame = CGRect(x: 16, y: 255, width: self.boxWidth, height: 68)
                    self.gardenView.frame = CGRect(x: 16, y: 339, width: self.boxWidth, height: 68)
            }, completion: { (true) in

            })
        }

        // Snap back above partial (y)
        if currentY > partialY || currentY < partialY && currentY > halfWayPoint
        {
            self.animator?.stopAnimation(true)
            UIView.animate(withDuration:0.62, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations:
                {
                    recognizer.view!.frame = CGRect(x: 0, y: partialY, width: self.frame.width, height: self.frame.height)
                    self.requestButton.alpha = 1
                    self.houseView.frame = CGRect(x: 16, y: 87+200, width: self.boxWidth, height: 68)
                    self.officeView.frame = CGRect(x: 16, y: 171+200, width: self.boxWidth, height: 68)
                    self.carView.frame = CGRect(x: 16, y: 255+200, width: self.boxWidth, height: 68)
                    self.gardenView.frame = CGRect(x: 16, y: 339+200, width: self.boxWidth, height: 68)
            }, completion: { (true) in

            })
        }

Answer 1

我通过添加 布尔值 来检查视图当前是否展开然后根据 true 或 false 解决了这个问题我加载相应的动画。我知道这不是最好的做事方式，因为您可以 return 动画到其原始位置而无需编写太多代码。无论如何，它有效，所以我会使用它。

顺便说一句，我非常欢迎任何可以帮助改进此代码的人，它确实需要一些 TLC。

这是我的 处理我的 panGestureRecogniser

的整个方法

// MARK: - Pan gesture

@objc func panGesture(recognizer: UIPanGestureRecognizer) {
    let window = UIApplication.shared.keyWindow
    let translation = recognizer.translation(in: self)
    let currentY = self.frame.minY
    let partialY = (window?.frame.height)!-194
    let halfWayPoint = ((window?.frame.height)!/2)-40

    self.frame = CGRect(x: 0, y: currentY + translation.y, width: self.frame.width, height: self.frame.height)
    recognizer.setTranslation(CGPoint.zero, in: self)

    switch recognizer.state {
    case .began:
        print("Began")

        if isExpanded
        {
            animator = UIViewPropertyAnimator(duration: 0.18, curve: .easeInOut, animations: {
                self.requestButton.alpha = 1
                self.houseView.alpha = 0
                self.officeView.alpha = 0
                self.gardenView.alpha = 0
                self.carView.alpha = 0
                self.houseView.frame = CGRect(x: 16, y: 87+200, width: self.boxWidth, height: 68)
                self.officeView.frame = CGRect(x: 16, y: 171+200, width: self.boxWidth, height: 68)
                self.carView.frame = CGRect(x: 16, y: 255+200, width: self.boxWidth, height: 68)
                self.gardenView.frame = CGRect(x: 16, y: 339+200, width: self.boxWidth, height: 68)
            })
            self.animator?.isReversed = true
        }
        else
        {
            animator = UIViewPropertyAnimator(duration: 0.18, curve: .easeInOut, animations: {
                self.requestButton.alpha = 0
                self.houseView.alpha = 1
                self.officeView.alpha = 1
                self.gardenView.alpha = 1
                self.carView.alpha = 1
                self.houseView.frame = CGRect(x: 16, y: 87, width: self.boxWidth, height: 68)
                self.officeView.frame = CGRect(x: 16, y: 171, width: self.boxWidth, height: 68)
                self.carView.frame = CGRect(x: 16, y: 255, width: self.boxWidth, height: 68)
                self.gardenView.frame = CGRect(x: 16, y: 339, width: self.boxWidth, height: 68)
            })
            self.animator?.isReversed = false
        }

        animator?.startAnimation()
        animator?.pauseAnimation()

    case .changed:

        // Property animator
        let offset: CGFloat = window!.frame.height-194
        let fraction: CGFloat = (offset-currentY)/4
        let percentage = fraction/100
        print(percentage)
        animator?.fractionComplete = CGFloat(percentage)

        // Prevent scrolling up past y:0
        if currentY <= 0
        {
            self.frame = CGRect(x: 0, y: 0, width: self.frame.width, height: self.frame.height)
        }

    case .ended:

        // Snap to 80 (y) (expanded)
        if currentY < 80 || currentY > 80 && currentY < halfWayPoint
        {
            self.animator?.stopAnimation(true)
            UIView.animate(withDuration:0.62, delay: 0.0, usingSpringWithDamping: 0.62, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations:
                {
                    recognizer.view!.frame = CGRect(x: 0, y: 80, width: self.frame.width, height: self.frame.height)
                    self.requestButton.alpha = 0
                    self.houseView.alpha = 1
                    self.officeView.alpha = 1
                    self.gardenView.alpha = 1
                    self.carView.alpha = 1
                    self.houseView.frame = CGRect(x: 16, y: 87, width: self.boxWidth, height: 68)
                    self.officeView.frame = CGRect(x: 16, y: 171, width: self.boxWidth, height: 68)
                    self.carView.frame = CGRect(x: 16, y: 255, width: self.boxWidth, height: 68)
                    self.gardenView.frame = CGRect(x: 16, y: 339, width: self.boxWidth, height: 68)
            }, completion: { (true) in
                self.isExpanded = true
            })
        }

        // Snap back to partial (y) (original position)
        if currentY > partialY || currentY < partialY && currentY > halfWayPoint
        {
            self.animator?.stopAnimation(true)
            UIView.animate(withDuration:0.62, delay: 0.0, usingSpringWithDamping: 0.62, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations:
                {
                    recognizer.view!.frame = CGRect(x: 0, y: partialY, width: self.frame.width, height: self.frame.height)
                    self.requestButton.alpha = 1
                    self.houseView.alpha = 0
                    self.officeView.alpha = 0
                    self.gardenView.alpha = 0
                    self.carView.alpha = 0
                    self.houseView.frame = CGRect(x: 16, y: 87+200, width: self.boxWidth, height: 68)
                    self.officeView.frame = CGRect(x: 16, y: 171+200, width: self.boxWidth, height: 68)
                    self.carView.frame = CGRect(x: 16, y: 255+200, width: self.boxWidth, height: 68)
                    self.gardenView.frame = CGRect(x: 16, y: 339+200, width: self.boxWidth, height: 68)
            }, completion: {(true) in
                self.isExpanded = false
            })
        }

    case .cancelled:
        print("Cancelled")

    case .failed:
        print("Failed")

    default:
        print("Default")
    }
}

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Swift 如何使用属性带有平移手势的动画器