Fade in/out 一系列点的动画

Question

我有一个上传 UIButton 并且我正在尝试实现一个动画，其中我有一组单独的点在按钮下方水平排列并且最左边的点淡出 in/out ，然后让它旁边的点淡出 in/out，依此类推一直到最右边的点，然后从左边重新开始循环。我可以让这个对一个点起作用，但是对多个点来说最有效的方法是什么？

func dotAnimation(){
    let xCoord = self.recButt.frame.origin.x + 25
    let yCoord = self.recButt.frame.origin.y + 5
    let radius = 3

    let dotPath = UIBezierPath(ovalIn: CGRect(x: Int(xCoord), y: Int(yCoord), width: radius, height: radius))
    let layer = CAShapeLayer()
    layer.path = dotPath.cgPath
    layer.strokeColor = UIColor(red: 95.00/255, green: 106.00/255, blue: 255/255, alpha: 1.00).cgColor
    self.view.layer.addSublayer(layer)

    let animation : CABasicAnimation = CABasicAnimation(keyPath: "opacity");
    animation.autoreverses = true
    animation.fromValue = 0
    animation.toValue = 1
    animation.duration = 2.0
    layer.add(animation, forKey: nil)
}

Answer 1

您正在描述 CAReplicatorLayer。这是一个做你想要的事情的人，使用条而不是点：

这是它的代码。注意只有一个红条层；复制成五个，偏移淡化动画，由包含复制器层处理：

    let lay = CAReplicatorLayer()
    lay.frame = CGRect(0,0,100,20)
    let bar = CALayer()
    bar.frame = CGRect(0,0,10,20)
    bar.backgroundColor = UIColor.red.cgColor
    lay.addSublayer(bar)
    lay.instanceCount = 5
    lay.instanceTransform = CATransform3DMakeTranslation(20, 0, 0)
    let anim = CABasicAnimation(keyPath: #keyPath(CALayer.opacity))
    anim.fromValue = 1.0
    anim.toValue = 0.2
    anim.duration = 1
    anim.repeatCount = .infinity
    bar.add(anim, forKey: nil)
    lay.instanceDelay = anim.duration / Double(lay.instanceCount)
    // and now just add `lay` to the interface

Answer 2

这里是动画三点任意的另一个版本UILabel

private var displayLink: CADisplayLink?

private var loadingLabeltext: String = ""
private var loadingLabel: UILabel? = {
    let label = UILabel()
    label.textColor = UIColor.appRed
    label.textAlignment = .center
    label.font = UIFont.init(name: "CirceRounded-Bold", size: 15)
    label.minimumScaleFactor = 0.6
    return label
}()

override func viewDidLoad(_ animated: Bool) {
    super.viewDidLoad(animated)
    
    view.addSubview(loadingLabel!)
    loadingLabel!.text = "Loading ..."
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    
    animateLabelDots(label: loadingLabel!)
}

private func animateLabelDots(label: UILabel) {
    guard var text = label.text else { return }
    text = String(text.dropLast(3))
    loadingLabeltext = text
    displayLink = CADisplayLink(target: self, selector: #selector(showHideDots))
    displayLink?.add(to: .main, forMode: .common)
    displayLink?.preferredFramesPerSecond = 4
}

@objc private func showHideDots() {
    if !loadingLabeltext.contains("...") {
        loadingLabeltext = loadingLabeltext.appending(".")
    } else {
        loadingLabeltext = "Loading "
    }
    
    loadingLabel!.text = loadingLabeltext
}

当您想停止它时，只需像这样使显示 link 无效并初始化即可：

private func hideLoadingSpinner() {
    displayLink?.invalidate()
    displayLink = nil
    
    UIView.animate(withDuration: 0.5, animations: {
        loadingLabel?.text = "Finished!"
        loadingLabel?.alpha = 0
    })
}

Fade in/out 一系列点的动画

Fade in/out animation for a series of dots

ios

swift3

uiviewanimation

cabasicanimation