用于Tinder风格的滑动屏幕的Swift iOS动画

Question

我已经构建了一个非常类似于Tinder主屏幕的屏幕。我已经在可拖动图标上设置了边框，并通过从屏幕顶部进行动画加载下一张卡片。此刻有2个按钮（1个接受按钮，1个拒绝按钮），当按下它们时，卡会旋转并以正确的方向从屏幕转换出来。此功能目前完成此动画......

byte

和

func rejectAnimation() {

    let scale = CGAffineTransformMakeScale(1, 1)
    let translate = CGAffineTransformMakeTranslation(0, 0)
    self.cardUIView.transform = CGAffineTransformConcat(scale, translate)

    springWithCompletion(0.75, animations: {

        let rotate = CGAffineTransformMakeRotation(CGFloat(-M_PI_2))
        let translate = CGAffineTransformMakeTranslation((-375), 0)
        self.cardUIView.transform = CGAffineTransformConcat(rotate, translate)

        }, completion: { finished in 0
            self.refreshView()
    })
}

我的问题是这个。我如何设置动画，以便当用户拖动卡片并将其放到右侧或左侧边界外时，卡片会在重置为新卡片之前按照刷卡的方向从屏幕上转换出来？

注意：springWithCompletion是一个在一段时间内在其中执行动画的函数。

Answer 1

检查一下。写于swift 4

func beingDragged(_ gestureRecognizer: UIPanGestureRecognizer) {

    xFromCenter = gestureRecognizer.translation(in: self).x
    yFromCenter = gestureRecognizer.translation(in: self).y
    switch gestureRecognizer.state {

    case .began:
        originalPoint = self.center;
        break;

    case .changed:
        let rotationStrength = min(xFromCenter / ROTATION_STRENGTH, ROTATION_MAX)
        let rotationAngel = .pi/8 * rotationStrength
        let scale = max(1 - fabs(rotationStrength) / SCALE_STRENGTH, SCALE_MAX)
        center = CGPoint(x: originalPoint.x + xFromCenter, y: originalPoint.y + yFromCenter)
        let transforms = CGAffineTransform(rotationAngle: rotationAngel)
        let scaleTransform: CGAffineTransform = transforms.scaledBy(x: scale, y: scale)
        self.transform = scaleTransform
        updateOverlay(xFromCenter)
        break;

    case .ended:
        afterSwipeAction()
        break;

    case .possible:break
    case .cancelled:break
    case .failed:break
    }
}

https://github.com/nickypatson/TinderSwipeView

感谢

Answer 2

只需使用UIPanGestureRecognizer并计算两点之间的差异，以了解动画的方向（处理程序被多次调用）。如果你需要同时为x和y轴设置动画，那么它会变得更加复杂。

let panGesture = UIPanGestureRecognizer(target: self, action: Selector("onPan:"))
cardView.addGestureRecognizer(panGesture)

func onPan(gestureRecognizer: UIPanGestureRecognizer) {
    let point = gestureRecognizer.locationInView(maskView)