Call Swift ViewController from Obj C didSelectionRow

Question

I have an Obj C project that I have added a Swift viewController to.

I'm trying to attach a storyboard to the viewController.

I can programmatically add things to the view but I can not get the storyboard to show up.

I have also tried to use a xib as a vie for the Swift viewController with no luck.

Calling the Swift vie form Obj C from a didSelectRowAtInexPath:

SwiftController *sc = [[SwiftController alloc] init];
[self.navigationController pushViewController:sc animated:YES];

SwiftController.swift:

import Foundation
import UIKit

@objc class SwiftController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

        // This prints
        println("in the scrolling view")
        // This works
        self.view.backgroundColor = .redColor();
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

Storyboard is hooked up correctly:

And this is what I get every time:

Same results happen with a xib.

There are a lot of things in the Apple Docs and on the web and here on SO that deal with many issues "around" this one but I have not found anything that helps me see what I'm doing wrong here. Doing things the way that works or Obj C does not seem to work. Clearly I'm a noob with Swift. Any help would be great. Thanks.

Answer 1

There are two basic approaches when using storyboards:

1. When you have Objective-C code that needs to transition to another scene in the storyboard, you can:

   • give that destination scene a storyboard id (e.g. SwiftControllerScene) in Interface Builder;

   • use the storyboard instantiateViewControllerWithIdentifier to instantiate that destination view controller; and

   • transition to that new scene (i.e. push or present that view controller).

   Thus:

   SwiftController *sc = [self.storyboard instantiateViewControllerWithIdentifier:@"SwiftControllerScene"];
   [self.navigationController pushViewController:sc animated:YES];
   

2. Alternatively, when using storyboards, rather than manually instantiating the destination's view controller and then calling pushViewController, I'd prefer to set up a segue in the storyboard between the view controllers (see https://stackoverflow.com/a/27650207/1271826). I'd then programmatically perform the segue (referencing, of course, whatever storyboard identifier you gave the segue):

   [self performSegueWithIdentifier:@"SegueToSwiftScene" sender:self];
   

   This way, the storyboard continues to represent the visual flow of the app.

Note, the fact that the destination scene's view controller is written in Swift vs Objective-C is largely immaterial. The question is merely what language the source view controller uses (hence the above examples are in Objective-C) and the process is otherwise largely the same regardless of the language of the destination view controller.

Answer 2

Because in this case, you're initializing a new SwiftController instead of using the one from the storyboard. You will want to either perform a segue to the new storyboard vc or get the vc from

self.storyboard.instantiateViewControllerWithIdentifier(_controller id_)

Answer 3

in case you use a xib for your swift viewController you must init it like this:

SwiftController* controller = [[SwiftController alloc]  initWithNibName:@"SwiftController" bundle:nil]

Where SwiftController is also the name of your xib.

I notice this issue in iOS 8, but it works normally in iOS 9 and iOS 10 when you init the controller simply like this:

SwiftController* controller = [[SwiftController alloc]  init];