ios - 自定义转场 : Going from Top to Bottom

Question

我试图通过让源 View Controller 从上到下进行连接。我可以让过渡从上到下进行，但是当过渡发生时，有一个从上到下的黑色矩形。一旦完成，目标 View Controller 就会弹出。有人知道如何解决这个问题吗？我正在使用本教程:http://www.appcoda.com/custom-segue-animations/并改变它的一部分来完成我想要它做的事情。

import UIKit

class FirstCustomSegue: UIStoryboardSegue {
    override func perform() {
        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, 0, 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(2, animations: { () -> Void in
            firstVCView.frame = CGRectOffset(firstVCView.frame, 0.0, screenHeight)
            secondVCView.frame = CGRectOffset(secondVCView.frame, 0.0, screenHeight)

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

    }
}

Answer 1

像这样更新你的代码，它现在能正常工作了吗？

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