问题描述
如何快速实现类似于以下的效果：
How can I make a effect in swift similar to this:
我希望动画能够永远循环。
I want the animation to loop forever.
推荐答案
对于iOS
UIViewAnimationOptions set提供了方便的选项，以实现精美和复杂的动画组合。对于您的特定情况，您将需要两个选项。
UIViewAnimationOptions set provides different handy options to achieve a combination of beautiful and complex animations. For your particular scenario you will require two of the options.
UIViewAnimationOptions.Repeat
UIViewAnimationOptions.AutoReverse
查看下面的代码以进行实施。
Check out the code below for implementation.
代码：
class MyViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let view = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
view.backgroundColor = UIColor.blueColor()
self.view.addSubview(view)
UIView.animateWithDuration(1,
delay: 0,
options: [UIViewAnimationOptions.Autoreverse, UIViewAnimationOptions.Repeat],
animations: {
view.backgroundColor = UIColor.clearColor()
},
completion: nil)
}
}
说明：
我已经创建了一个具有特定框架的视图以进行演示。
Explanation:I have created a view with a specific frame for demo purpose.
您感兴趣的部分是 UIView .animateWithDuration 方法。请注意，我在 options 参数中提供了数组 [UIViewAnimationOptions.AutoReverse，UIViewAnimationOptions.Repeat] 。
The part you are interested in is the UIView.animateWithDuration method. Notice that I have provided an array [UIViewAnimationOptions.AutoReverse, UIViewAnimationOptions.Repeat] in the options parameter.
这两个选项足以实现平滑且永久的循环动画，如下所示。
These two options are enough to achieve a smooth and forever looping animation like below.https://s3.amazonaws.com/uploads.hipchat.com/37040/1764070/6Iow7n7WiWf6Naz/autoReverse.gif
如果您不想反转动画，只需删除 UIViewAnimationOptions.AutoReverse 从数组中的 options 参数中。您将获得这样的动画。
If you don't want to reverse the animation, just remove UIViewAnimationOptions.AutoReverse from the array in the options parameter. You will get an animation like this.https://s3.amazonaws.com/uploads.hipchat.com/37040/1764070/8fyRUlzqNHSQI47/noreverse.gif
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