Question

我正在尝试使用两个视图创建动画，并且在执行时遇到了一些意外行为。

我想在制作第二个动画transitionFlipFromBottom

时为两个视图位置设置动画

以下是代码：

let initialFrame = CGRect(x: xpos, y: -310, width: 300, height: 300)

let firstView = UIView()
firstView.backgroundColor = .red
firstView.frame = initialFrame

let secondView = UIView()
secondView.backgroundColor = .white
secondView.frame = initialFrame
secondView.isHidden = false


self.view.addSubview(firstView)
self.view.addSubview(secondView)


// Here I try to move the views on screen while fliping them
UIView.animate(withDuration: 1, delay: 0, options: .curveEaseOut, animations: {
    secondView.center = self.view.center
    firstView.center = self.view.center
    self.flip(firstView: firstView, secondView: secondView)
}, completion: nil)



// This function flips the views vertically while it animates the transition from the first to the second view
fileprivate func flip(firstView: UIView, secondView: UIView) {
    let transitionOptions: UIViewAnimationOptions = [.transitionFlipFromBottom, .showHideTransitionViews]
    UIView.transition(with: firstView, duration: 0.5, options: transitionOptions, animations: {
        firstView.isHidden = true
    })

    UIView.transition(with: secondView, duration: 0.5, options: transitionOptions, animations: {
        secondView.isHidden = false
    })
}

上面的代码无法同时执行这两个动画。

只有在第一个动画（移动框架）完成后，在flip块内放置completion函数调用时，它才有效，如下所示：

UIView.animate(withDuration: 1, delay: 0, options: .curveEaseOut, animations: {
    secondView.center = self.view.center
    firstView.center = self.view.center
}, completion: {(_) in
    self.flip(firstView: dummyView, secondView: newGroupView)
})

我甚至尝试使用UIView.animateKeyframes，但它仍无效。

我在这里遗漏了什么吗？

谢谢。

Answer 1

有几件事：

在transition中，指定.allowAnimatedContent选项。

推迟动画：

DispatchQueue.main.async {
    UIView.animate(withDuration: 1, delay: 0, options: [.curveEaseOut], animations: {
        secondView.center = CGPoint(x: self.view.bounds.midX, y: self.view.bounds.midY)
        firstView.center = CGPoint(x: self.view.bounds.midX, y: self.view.bounds.midY)
        self.flip(firstView: firstView, secondView: secondView)
    }, completion: { _ in
    })
}

有些不相关，你不想要：
```
secondView.center = self.view.center
```
相反，请执行：
```
secondView.center = CGPoint(x: self.view.bounds.midX, y: self.view.bounds.midY)
```
您想在secondView.center的{{1}}的坐标空间中设置bounds，而不是view的{{1}}。
< / LI>

同时运行两个动画

1 个答案: