以随机延迟（一个接一个）和随机水平位置动画滚动图像

Question

我有一张包含 x 张图片的列表。对于每个图像，我创建一个 UIImageView，其中 y 是视图高度，随机 x

func computeImageFrame() -> CGRect {
    let imageWidth: CGFloat = 91
    let imageHeight: CGFloat = 131

    var x = xPos()
    let y = yPos()

    if (x > ((self.backgroundView?.bounds.width)! - (self.backgroundView?.bounds.width)! * 0.20)){
        x = x.truncatingRemainder(dividingBy: ((self.backgroundView?.bounds.width)! - (self.backgroundView?.bounds.width)! * 0.20))}

    return CGRect(x: x, y: y, width: imageWidth, height: imageHeight)
}

哪里

func xPos() -> CGFloat {
    return CGFloat(arc4random_uniform(UInt32((self.backgroundView?.frame.size.width)!)))
}
func yPos() -> CGFloat {
    return self.backgroundView.bounds.height
}

此时，我在 UIImageViews 上有一个列表，其中 x 是随机的，y 是 viewHeight，现在我正在尝试制作动画

func animateBackgroundFor(_ imageViews: [UIImageView]) {
    for imageView in imageViews {
        self.backgroundView.addSubview(imageView)
    }

    // Animate background
    UIView.animate(withDuration: 6.0, delay: 0.0, options: [UIViewAnimationOptions.repeat, UIViewAnimationOptions.curveLinear], animations: {
        for imageView in imageViews {
            imageView.frame = imageView.frame.offsetBy(dx: 0.0, dy: -7 * imageView.frame.size.height)
        }
    }, completion: nil)
}

我的问题是如何让它们一个接一个地拍摄，而不是同时拍摄，以及如何在每次循环时重新计算每张图像的水平位置。

谢谢

编辑：忘记说了，我试过了

func animateBackgroundFor(_ imageViews: [UIImageView]) {
    for imageView in imageViews {
        self.backgroundView.addSubview(imageView)
    }
    for imageView in imageViews {
        UIView.animate(withDuration: 6.0, delay: 1.2, options: [UIViewAnimationOptions.repeat, UIViewAnimationOptions.curveLinear], animations: {
            imageView.frame = imageView.frame.offsetBy(dx: 0.0, dy: -7 * imageView.frame.size.height)
        }, completion: nil)
    }
}

Answer 1

尝试以下解决方案。添加到您的控制器私有属性：

private var imageViews = [UIImageView]()

然后这样修改你的animateBackgroundFor(_)方法：

func animateBackgroundFor(_ imageViews: [UIImageView]) {
    for imageView in imageViews {
        self.backgroundView.addSubview(imageView)
    }
    self.imageViews = imageViews
    animateImage(at: 0)
}

func animateImage(at index: NSInteger) {
    guard index >= 0 && index < imageViews.count else { return }
    let imageView = imageViews[index]
    imageView.frame = computeImageFrame()

    UIView.animate(withDuration: 6.0,
                   delay: 0.0,
                   options: UIViewAnimationOptions.curveLinear,
                   animations: { 
                    imageView.frame = imageView.frame.offsetBy(dx: 0.0, dy: -7 * imageView.frame.size.height)
    },
                   completion: {
        [weak self] finished in
                    guard finished && self != nil else { return }
                    let nextIndex = index + 1 < self!.imageViews.count ? index + 1 : 0
                    self!.animateImage(at: nextIndex)
    })
}

以随机延迟（一个接一个）和随机水平位置动画滚动图像

Animate scrolling images with random delay (one after another) and random horizontal position

animation

uiview

uiviewanimation

swift