UIStoryboardSegue：动画期间不显示视图

Question

当我的自定义segue动画正在执行时，目标视图显示为黑色。动画结束后，视图会显示并且看起来很好。

以下是截图：

动画场景：

完成segue /动画后查看：

这是自定义segue类：

class SegueToPreview: UIStoryboardSegue {

override func perform() {
    // Assign the source and destination views to local variables.
    var firstVCView = self.sourceViewController.view as UIView!
    var secondVCView = self.destinationViewController.view as UIView!

    // Get the screen width and height.
    let screenWidth = UIScreen.mainScreen().bounds.size.width
    let screenHeight = UIScreen.mainScreen().bounds.size.height

    // Specify the initial position of the destination view.
    secondVCView.frame = CGRectMake(0.0, screenHeight, screenWidth, screenHeight)

    // Access the app's key window and insert the destination view above the current (source) one.
    let window = UIApplication.sharedApplication().keyWindow
    window?.insertSubview(secondVCView, aboveSubview: firstVCView)

    // Animate the transition.
    UIView.animateWithDuration(0.2, animations: { () -> Void in

        firstVCView.frame = CGRectOffset(firstVCView.frame, -screenWidth, 0.0)
        secondVCView.frame = CGRectOffset(secondVCView.frame, -screenWidth, 0.0)

        }) { (Finished) -> Void in
            self.sourceViewController.presentViewController(self.destinationViewController as! UIViewController,
                animated: false,
                completion: nil)
    }

}

虽然展开segue工作得很好，但同时显示两个视图。

我认为在执行动画时未加载视图，但不知道如何修复它。

Answer 1

目标vc视图的初始位置设置不正确（假设您希望视图从右侧移入）;你把它放在屏幕下方，而不是屏幕右侧，

secondVCView.frame = CGRectMake(0.0, screenHeight, screenWidth, screenHeight)

这应该是，

secondVCView.frame = CGRectMake(screenWidth, 0, screenWidth, screenHeight)