ios - 用于 Tinder 风格滑动屏幕的 Swift iOS 动画

Question

我构建了一个与 Tinder 主屏幕非常相似的屏幕。我已经在可拖动图标上设置了边框，下一张卡片通过从屏幕顶部动画加载。目前有 2 个按钮(1 个接受按钮，1 个拒绝按钮)，当它们被按下时，卡片会旋转并以正确的方向从屏幕中移出。这个函数目前完成这个动画...

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()
    })
}

和

func acceptAnimation() {

    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()
    })
}

我的问题是这样的。我如何制作动画，以便当用户将卡片拖放到右侧或左侧边界之外时，卡片会继续按照在重置为新卡片之前滑动的方向平移出屏幕？

注意:springWithCompletion 是一个在特定时间段内执行动画的函数。

Answer 1

检查一下。用swift 4写的

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

谢谢