在隐藏Label之前，UIView动画没有完成

Question

我的标签在动画运行之前就消失了。

按下按钮后动画应该会运行并滑出标签和按钮。但是当我按下按钮时，它们都会被隐藏，然后动画才能将它们滑出来。

2017-11-15 23:26:17.321465 [2442:245232] Animation started
2017-11-15 23:26:20.325137 [2442:245232] Animation stopped

这是NSLog。据说它正在运行完整的动画......

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提前感谢您的帮助！

Answer 1

您的代码完美无缺：

因此，不告诉我们的事情是造成问题的原因。

编辑：确实如此，您没有告诉我们的代码会导致问题。你告诉我们这个：

UIView.animate(withDuration: 3, delay: 0.0, options: .allowAnimatedContent, animations: {
        self.labelWinningPlayer.center = CGPoint(x: self.labelWinningPlayer.center.x + 500, y: self.labelWinningPlayer.center.y)
        self.buttonNextGameLabel.center = CGPoint(x: self.buttonNextGameLabel.center.x + 500, y: self.buttonNextGameLabel.center.y)
    }, completion: { (finished: Bool) in
        self.labelWinningPlayer.isHidden = true
        self.buttonNextGameLabel.isHidden = true
})

但是您没有告诉我们下一行行，这是：

labelWinningPlayer.center = CGPoint(x: labelWinningPlayer.center.x - 1000, y: labelWinningPlayer.center.y)
buttonNextGameLabel.center = CGPoint(x: buttonNextGameLabel.center.x - 1000, y: buttonNextGameLabel.center.y)

这些行取消了动画！

似乎你还没有理解动画是什么。首先制作动画，然后在动画之后完成 动画的任何内容，然后输入completion功能。但是这些行你想要在动画之后完成。所以把它们放到completion函数中！像这样：

UIView.animate(withDuration: 3, delay: 0.0, options: .allowAnimatedContent, animations: {
        self.labelWinningPlayer.center = CGPoint(x: self.labelWinningPlayer.center.x + 500, y: self.labelWinningPlayer.center.y)
        self.buttonNextGameLabel.center = CGPoint(x: self.buttonNextGameLabel.center.x + 500, y: self.buttonNextGameLabel.center.y)
    }, completion: { (finished: Bool) in
        self.labelWinningPlayer.isHidden = true
        self.buttonNextGameLabel.isHidden = true
        labelWinningPlayer.center = CGPoint(x: labelWinningPlayer.center.x - 1000, y: labelWinningPlayer.center.y)
        buttonNextGameLabel.center = CGPoint(x: buttonNextGameLabel.center.x - 1000, y: buttonNextGameLabel.center.y)
        // ... and everything else in the method goes here too
})

方法中的其他一切也需要移动到那里。 在完成动画之后发生的所有事情都会进入completion函数。这就是completion的含义！

Answer 2

将标签和按钮的超级视图clipsToBounds属性设置为true

UIView.animate(withDuration: 3, delay: 0.0, options: [], animations: {
        NSLog("Animation started")
        self.labelWinningPlayer.center = CGPoint(x: (self.labelWinningPlayer.center.x) * 3, y: self.labelWinningPlayer.center.y)
        self.buttonNextGameLabel.center = CGPoint(x: (self.buttonNextGameLabel.center.x) * 3, y: self.buttonNextGameLabel.center.y)
    }, completion: { (finished: Bool) in
        NSLog("Animation stopped")
        self.labelWinningPlayer.isHidden = true
        self.buttonNextGameLabel.isHidden = true
    })