Swift中的自定义Segue

Question

@objc(SEPushNoAnimationSegue)
class SEPushNoAnimationSegue: UIStoryboardSegue {
    override func perform () {
      self.sourceViewController.navigationController.pushViewController(self.destinationViewController, animated:false)
    }
}

In the above code, I have 2 questions: 1). it has a compile error: 'UINavigationController!' does not have a member named 'pushViewController'

But in that class, it did has a pushViewController method.

2). I have to add the annotation: @objc(SEPushNoAnimationSegue), otherwise, in storyboard, it only recognize the random generated name, like, _tcxxxxSEPushNoAnimationSegue.

why these 2 issues happen here?

Answer 1

Issue #1

UIStoryboardSegue has an irritating flaw: its sourceViewController and destinationViewController properties are typed as AnyObject! (that's the case even in Objective-C (Id type)) and not as UIViewController , as it should be.

That same flaw creates havoc in your perfect and simple code. Here's how to rewrite it in order to fix the compile errors:

@objc(SEPushNoAnimationSegue)
class SEPushNoAnimationSegue: UIStoryboardSegue {
    override func perform () {
        let src = self.sourceViewController as UIViewController
        let dst = self.destinationViewController as UIViewController
        src.navigationController.pushViewController(dst, animated:false)
    }
}

NOTE: Apple fixed this thing in iOS 9. sourceViewController and destinationViewController are now correctly declared as UIViewController .

Issue #2

The Swift compiler stores its symbols using its own name mangling , and good ol' Objective-C does not recognize it in Xcode. Using an explicit @obj() solves the issue.

Answer 2

This works fine for me

@objc(SEPushNoAnimationSegue) class SEPushNoAnimationSegue: UIStoryboardSegue {

override func perform() {
    let sourceViewController = self.sourceViewController as UIViewController
    let destinationViewController = self.destinationViewController as UIViewController

    sourceViewController.presentViewController(destinationViewController, animated: true, completion: nil)
}

}

Answer 3

Even Better:

import UIKit

class CustomSegue: UIStoryboardSegue {
    override func perform() {
        self.sourceViewController.presentViewController(self.destinationViewController as UIViewController, animated: false, completion: nil)
    }
}

Answer 4

Swift 3.0:

import UIKit

class CustomNoAnimationSegue: UIStoryboardSegue {

    override func perform() {
        if let navigation = source.navigationController {
            navigation.pushViewController(destination, animated: false)
        }
    }
}