ios - 隐藏标签之前，UIView 动画未完成

Question

我的标签在动画运行前就消失了。

动画应在按下按钮并滑出标签和按钮后运行。但是当我按下按钮时，在动画将它们滑出之前它们都被隐藏了。

func nextGame() {

    UIView.animate(withDuration: 3, delay: 0.0, options: .allowAnimatedContent, animations: {
            NSLog("Animation started")
            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
            NSLog("Animation stopped")
            self.labelWinningPlayer.isHidden = true
            self.buttonNextGameLabel.isHidden = true
    })


    //sets buttons to start position
    labelWinningPlayer.center = CGPoint(x: labelWinningPlayer.center.x - 1000, y: labelWinningPlayer.center.y)
    buttonNextGameLabel.center = CGPoint(x: buttonNextGameLabel.center.x - 1000, y: buttonNextGameLabel.center.y)

    //hides buttons that lay under the animated buttons 
    for i in 1...9 {

        if let button = view.viewWithTag(i) as? UIButton {
            button.setImage(nil, for: .normal)
        }
    }
    activeGame = true
}

//animation should get started with this button
@IBAction func buttenNextGameAction(_ sender: Any) {
    nextGame()
}

//slides buttons in
func slideNextGameButtons() {

    labelWinningPlayer.isHidden = false
    buttonNextGameLabel.isHidden = false

    UIView.animate(withDuration: 0.5, 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)
    })
}

这是 NSLog。据此，它正在运行完整的动画...

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

提前感谢您的帮助!

Answer 1

您的代码完美运行:

因此，无论问题是什么，您没有告诉我们的事情都是造成问题的原因。

编辑:是的，确实是您没有告诉我们的代码导致了问题。你告诉我们这件事:

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
})

但是你没有告诉我们下的内容，它们是:

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

那些行取消了动画!

看来你还没有明白什么是动画。您首先制作动画，然后在动画之后将您想要完成的任何事情放入completion 函数中。但是那些行是您希望在动画之后完成的事情。所以将它们放入 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
})

并且方法中的所有其他内容也需要移到那里。动画完成之后发生的所有事情都将进入completion 函数。这就是 completion 的意思!