Question

我已使用UIView animateWithDuration来增加下面代码中的shapeLayer.frame.size.height，但无论持续时间如何，它都会非常快速地生成动画。我发现推荐的一些帖子使用了我已经完成的一些延迟时间，但它仍然很快动画，忽略了我设置的5秒持续时间。

private let minimalHeight: CGFloat = 50.0  
private let shapeLayer = CAShapeLayer()

override func loadView() {  
super.loadView()

shapeLayer.frame = CGRect(x: 0.0, y: 0.0, width: view.bounds.width, height: minimalHeight)
shapeLayer.backgroundColor = UIColor(red: 57/255.0, green: 67/255.0, blue: 89/255.0, alpha: 1.0).CGColor
view.layer.addSublayer(shapeLayer)

  }

func delay(delay:Double, closure:()->()) {
    dispatch_after(
        dispatch_time(
            DISPATCH_TIME_NOW,
            Int64(delay * Double(NSEC_PER_SEC))
        ),
        dispatch_get_main_queue(), closure)
}


override func viewDidAppear(animated: Bool) {
   delay(3)    {

    UIView.animateWithDuration(5.0) {
        self.shapeLayer.frame.size.height += 400.0
        }
    }

如何在5秒内完成动画制作？

Answer 1

试一试：

override func viewDidAppear(animated: Bool) {

    //You should not edit directly the frame here, or the change will be committed ASAP. Frame does not act like constraints.
    // create the new frame
    var newFrame = self.shapeLayer.frame
    newFrame.size.height += 400.0

    UIView.animateWithDuration(5.0, delay: 3.0, options: .CurveEaseOut, animations: {
        //assign the new frame in the animation block
        self.shapeLayer.frame = newFrame
    }, completion: { finished in

    })
}

Answer 2

也许你应该尝试CABasicAnimation

    let fromValue = view2.layer.bounds.height
    let toValue = view2.layer.bounds.height + 50
    CATransaction.setDisableActions(true) //Not necessary
    view2.layer.bounds.size.height = toValue
    let positionAnimation = CABasicAnimation(keyPath:"bounds.size.height")
    positionAnimation.fromValue = fromValue
    positionAnimation.toValue = toValue
    positionAnimation.duration = 1
    view2.layer.addAnimation(positionAnimation, forKey: "bounds")

Answer 3

不是将更改放在动画块内，而是在动画之前进行更改。
然后，在动画中，只调用superView.layoutIfNeeded（）

它对我有用，参考：How do I animate constraint changes?

Answer 4

在我的情况下，问题是代码动画中的其他地方被禁用了：

[UIView setAnimationsEnabled:false];

将其更改为真实即可解决问题：

[UIView setAnimationsEnabled:true];

UIView animateWithDuration太快了

4 个答案: