我有一个倒计时的动画计时器栏，我希望能够在满足某些条件时取消动画并重置栏，这样它就不会一直到 0。同样，如果它确实做到了到 0 我想调用一个函数。
现在我只连接了一个按钮进行测试。再次按下按钮确实可以防止它一直向下，但它会在屏幕上弹跳，并且完成块中的打印语句总是返回 true。我认为多个动画彼此堆叠在一起。
如何停止动画？
var countDownBar = UIView()
var button = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
// Place the countDownBar in the center of the view
countDownBar.frame = CGRectMake(0, 0, 150, 15)
countDownBar.center = view.center
countDownBar.backgroundColor = UIColor.blueColor()
view.addSubview(countDownBar)
// Add in a button
button = UIButton.buttonWithType(UIButtonType.System) as UIButton
button.frame = CGRectMake(0, 0, 50, 20)
button.center = CGPointMake(view.center.x, view.center.y + 30)
button.backgroundColor = UIColor.lightGrayColor()
button.setTitle("button", forState: UIControlState.Normal)
button.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside)
view.addSubview(button)
}
// Do this when the button is pressed
func buttonAction (sender: UIButton) {
// Shrink the bar down to 0 width
UIView.animateWithDuration(3.0,
animations: ({
self.countDownBar.frame = CGRectMake(self.countDownBar.frame.minX, self.countDownBar.frame.minY, 0, self.countDownBar.frame.height)
}),
completion: {finished in
// When finished, reset the bar to its original length
self.countDownBar.frame = CGRectMake(0, 0, 150, 15)
self.countDownBar.center = self.view.center
// Display if completed fully or interrupted
if finished {
print("animation finished")
} else {
print("animation interrupted")
}
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}