从UICollectionView cellForItemAt indexPath为CAShapeLayer动画设置toValue

时间:2017-12-15 20:18:19

标签: swift animation uicollectionview cashapelayer

我有以下几个部分: - 我的主视图是一个带有UICollectionView的UIViewController - UICollectionView的单元格 - 使用CABasicAnimation构建CAShapeLayer的UIView的子类

在我的主视图中,我有一个UICollectionView,它会渲染一堆带有标签等的单元格。它还显示了一个进度图。

在我的子类ProgressCirclePath()中,我正在绘制一个CAShapeLayer,它充当在我的UICollectionView的每个单元格中呈现的进度图。

我已经能够将数据传递到每个单元格,例如标签以及CAShapeLayer strokeEnd值。

在我尝试将CABasicAnimation添加到路径之前,一切都很好。在这种情况下,我无法设置动画toValue的值。使用打印控制台测试显示该值在我的UICollectionView中可用,但在我的子类中的动画块中不可用(它只是返回nil)。我试过简单地设置toValue以及在我的ProgressCirlePath中创建一个变量并从UICollectionView设置它。都没有奏效。

我很欣赏有关为什么会发生这种情况以及如何解决这个问题的任何提示。谢谢!

在我的UICollectionView中:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
      let cell = decksCollectionView.dequeueReusableCell(withReuseIdentifier: "DeckCell", for: indexPath) as! DeckCell

  cell.creatorLabel.text = deckCellCreator[indexPath.item]
  cell.titleLabel.text = deckCellTitle[indexPath.item]
  cell.progressLabel.text = "\(deckCellCompletionPercentage[indexPath.item])%"

  cell.progressGraphView.animation.toValue = CGFloat(deckCellCompletionPercentage[indexPath.item])/100

  return cell
}

我的单元格类中的设置:

let progressGraphView: ProgressCirclePath = {
    let circlePath = ProgressCirclePath(frame: CGRect(x:0, y:0, width: 86, height: 86))
    circlePath.progressLayer.position = circlePath.center
    circlePath.progressBackgroundLayer.position = circlePath.center
    circlePath.translatesAutoresizingMaskIntoConstraints = false
    return circlePath
}()

这里是我的ProgressCirclePath()

class ProgressCirclePath: UIView {
let progressLayer = CAShapeLayer()
let progressBackgroundLayer = CAShapeLayer()
let animation = CABasicAnimation(keyPath: "strokeEnd")
//    var percentageValue = CGFloat()


override init(frame: CGRect) {
    super.init(frame: frame)

    layer.addSublayer(progressBackgroundLayer)
    layer.addSublayer(progressLayer)

    let circularPath = UIBezierPath(arcCenter: .zero, radius: 43, startAngle: 0, endAngle: 2*CGFloat.pi, clockwise: true)

    progressBackgroundLayer.path = circularPath.cgPath
    progressBackgroundLayer.lineWidth = 10
    progressBackgroundLayer.strokeStart = 0
    progressBackgroundLayer.strokeEnd = 1
    progressBackgroundLayer.strokeColor = UIColor(red: 221/255.0, green: 240/255.0, blue: 226/255.0, alpha: 1.0).cgColor
    progressBackgroundLayer.fillColor = UIColor.clear.cgColor
    progressBackgroundLayer.transform = CATransform3DMakeRotation(-CGFloat.pi/2, 0, 0, 1)

    progressLayer.path = circularPath.cgPath
    progressLayer.lineWidth = 10
    progressLayer.lineCap = kCALineCapRound
    progressLayer.strokeColor = UIColor(red: 72/255.0, green: 172/255.0, blue: 104/255.0, alpha: 1.0).cgColor
    progressLayer.fillColor = UIColor.clear.cgColor
    progressLayer.transform = CATransform3DMakeRotation(-CGFloat.pi/2, 0, 0, 1)


    animation.duration = 1
    animation.fromValue = 0
    // animation.toValue = percentageValue
    animation.fillMode = kCAFillModeForwards
    animation.isRemovedOnCompletion = false
    progressLayer.add(animation, forKey: "animateGraph")
    print("animation.toValue \(animation.toValue)")
}

required init?(coder aDecoder: NSCoder) {
    fatalError("has not been implemented")
}

}

1 个答案:

答案 0 :(得分:1)

您在自定义视图的生命周期中过早地处理数据和动画的注入。不要在对象的初始化程序中处理它们,而是将它们移到更晚的更合适的方法,例如layoutSubviews

override open func layoutSubviews() {
    super.layoutSubviews()

    // handle post-init stuff here, like animations and passing in data
    // when it doesn't get passed in on init

}