ios - 如果我显示 destinationViewController，自定义 Fade Segue 不会设置动画

Question

我已经编写了一个自定义 segue 来获得淡入淡出效果，我试图通过将 destination view controller 插入 source view controller 并设置动画来实现source view controller 的 alpha 为零。

但是，在源下方添加 destination view controller 似乎取消了动画，并且 segue 的执行就像是一个常规的 present 并且禁用了动画。

import UIKit

class FadeSegue: UIStoryboardSegue {

    override func perform() {
        // Get the view of the source
        let sourceViewControllerView = self.sourceViewController.view
        // Get the view of the destination
        let destinationViewControllerView = self.destinationViewController.view

        let screenWidth = UIScreen.mainScreen().bounds.size.width
        let screenHeight = UIScreen.mainScreen().bounds.size.height

        // Make the destination view the size of the screen
        destinationViewControllerView.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)

        if let window = UIApplication.sharedApplication().keyWindow {
            // Insert destination below the source
            // Without this line the animation works but the transition is not smooth as it jumps from white to the new view controller
            window.insertSubview(destinationViewControllerView, belowSubview: sourceViewControllerView)

            // Animate the fade, remove the destination view on completion and present the full view controller
            UIView.animateWithDuration(0.4, animations: {
                sourceViewControllerView.alpha = 0.0
                }, completion: { (finished) in
                    destinationViewControllerView.removeFromSuperview()
                    self.sourceViewController.presentViewController(self.destinationViewController, animated: false, completion: nil)
            })
        }
    }
}

Answer 1

你好，我想你需要的是这个

override func perform() {
        // Get the view of the source
        let sourceViewControllerView = self.sourceViewController.view
        // Get the view of the destination
        let destinationViewControllerView = self.destinationViewController.view

        let screenWidth = UIScreen.mainScreen().bounds.size.width
        let screenHeight = UIScreen.mainScreen().bounds.size.height

        // Make the destination view the size of the screen
        destinationViewControllerView.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)

            // Insert destination below the source
            // Without this line the animation works but the transition is not smooth as it jumps from white to the new view controller
            destinationViewControllerView.alpha = 0;
            sourceViewControllerView.addSubview(destinationViewControllerView);
            // Animate the fade, remove the destination view on completion and present the full view controller
            UIView.animateWithDuration(10, animations: {
                destinationViewControllerView.alpha = 1;
                }, completion: { (finished) in
                    destinationViewControllerView.removeFromSuperview()
                    self.sourceViewController.presentViewController(self.destinationViewController, animated: false, completion: nil)
            })
        }
    }

希望对你有帮助