swift - 防止关键帧动画完成后 View 弹回

Question

我有一个 View ，我正在以这样的方式对其进行动画处理，使其扩展并移动到 View Controller 中的一组新坐标。我正在使用关键帧执行此操作:

UIView.animateKeyframesWithDuration(0.5, delay: 0, options: .CalculationModeCubic, animations: {
    UIView.addKeyframeWithRelativeStartTime(0.0, relativeDuration: 0.5) {

        //Moving main View
        tappedView.frame = CGRectMake((self.screenSize.width/2)-250, (self.screenSize.height/2)-250, 500, 500)

    }
}, completion: nil)

问题在于，一旦动画完成， View 就会返回到其原始位置和大小。

有没有办法防止这种情况在 Swift 中发生？

Answer 1

如果使用自动布局，这是一个问题。在这种情况下，必须将最终坐标放入完成处理程序中才能使其正常工作。

swift 2

UIView.animateKeyframesWithDuration(0.5, delay: 0, options: .CalculationModeCubic, animations: {
    UIView.addKeyframeWithRelativeStartTime(0.0, relativeDuration: 0.5) {
        // Moving main View
        tappedView.frame = CGRectMake((self.screenSize.width/2)-250, (self.screenSize.height/2)-250, 500, 500)
    }
}, completion: {(finished: Bool) -> Void in
    tappedView.frame = CGRectMake((self.screenSize.width/2)-250, (self.screenSize.height/2)-250, 500, 500)
})

swift 3、4、5

UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: .calculationModeCubic, animations: {
    UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.5) {
        // Moving main View
        tappedView.frame = CGRect(x: (self.screenSize.width/2)-250, y: (self.screenSize.height/2)-250, width: 500, height: 500)
    }
}, completion: {(finished: Bool) -> Void in
    tappedView.frame = CGRect(x: (self.screenSize.width/2)-250, y: (self.screenSize.height/2)-250, width: 500, height: 500)
})