为什么SegmentedControl在swift中单击时会向后移动

Question

我在SegmentedControl函数中设置viewdidAppear的变换并更改SegmentedControl的位置，当我点击SegmentedControl时，SegmentedControl的位置发生变化（向后移动） ）

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)
    self.videoSegmented.transform = CGAffineTransformRotate(self.videoSegmented.transform, CGFloat(self.degreesToRadians(90)));
    var frame = self.videoSegmented.frame
    self.videoSegmented.frame = self.seguementView.frame
}

func degreesToRadians(x:Double) -> Double{
    return M_PI * x / 180
}