swift - 如何根据条件停止按钮动画

Question

我有一个函数可以让某个按钮动画淡入和淡出。我在 viewDidLoad 中启动动画，所以一旦我打开应用程序，动画就会开始工作。该按钮将我带到一个输入窗口，当输入字段有输入时，我希望动画停止。我尝试从有条件的文本中删除动画，但即使满足条件，动画也会保持动画效果。我如何创建删除此动画的函数？

这是我的代码:

func animateText(){

    UIView.animate(withDuration: 0.5, animations: {
        self.EnterDet.alpha = 1
    }, completion:  {
        (Comnpleted : Bool) -> Void in

        UIView.animate(withDuration: 0.5, delay: 1.5, options: UIViewAnimationOptions.allowUserInteraction, animations: {
        self.EnterDet.alpha = 0.1

        }, completion: {
            (Completed : Bool) -> Void in
            self.animateText()
        })
    })
}

Answer 1

更改完成 block 以检查 completed 参数。 completed 在动画完成时为 true(即未取消时)。只有当 completed 为 true 时，您才会调用动画的下一步。

UIView.animate(withDuration: 0.5, animations: {
    self.EnterDet.alpha = 1
}, completion:  {

(completed : Bool) -> Void in
    if completed {
        UIView.animate(withDuration: 0.5, delay: 1.5, options: UIViewAnimationOptions.allowUserInteraction, animations: {
            self.EnterDet.alpha = 0.1

        }, completion: {
            (completed : Bool) -> Void in
            if completed {
                self.animateText()
            } else {
                self.EnterDet.alpha = 1
            }
        })
    }
})

然后，当你想结束动画时，调用:

self.EnterDet.layer.removeAllAnimations()