iOS - Getting black view upon changing root view controller

Question

I am trying to change the root view controller upon the button taps from ViewController1 to ViewController2 and vice versa. Problem is I am getting black screen after I set my second view controller as root view controller. I am enclosing my code.

My AppDelegate.swift

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        let storyBoard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
        let vc1 = storyBoard.instantiateViewControllerWithIdentifier("VC1") as! VC1
        let nc = UINavigationController(rootViewController: vc1)
        self.window?.rootViewController = nc
        self.window?.makeKeyAndVisible()

        return true
    }

First View Controller (VC1.swift)

class VC1: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    deinit {
        print("Deinit of VC1")
    }

    @IBAction func btnTapped(sender: AnyObject) {
        let window = UIApplication.sharedApplication().windows[0]
        let rootNavigationControl = window.rootViewController as! UINavigationController

        let storyBoard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
        let vc2 = storyBoard.instantiateViewControllerWithIdentifier("VC2") as! VC2
        let nc = UINavigationController(rootViewController: vc2)

        rootNavigationControl.presentViewController(nc, animated: true) { () -> Void in
            // ------- Becomes black screen here ----------
            rootNavigationControl.viewControllers = [vc2]
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}

Second View Controller (VC2.swift)

class VC2: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    deinit {
        print("Deinit of VC2")
    }

    @IBAction func btnTapped(sender: AnyObject) {
        let window = UIApplication.sharedApplication().windows[0]
        let rootNavigationControl = window.rootViewController as! UINavigationController

        let storyBoard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
        let vc1 = storyBoard.instantiateViewControllerWithIdentifier("VC1") as! VC1
        let nc = UINavigationController(rootViewController: vc1)

        rootNavigationControl.presentViewController(nc, animated: true) { () -> Void in
            rootNavigationControl.viewControllers = [vc1]
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}

Please can somebody help me out in figuring what is the problem. Thanks in advance for all the help.

score 1 · Answer 1 · answered Oct 28 '15 at 20:56

I would do something like this:

AppDelegate.swift

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool
{
    let storyBoard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
    let vc1 = storyBoard.instantiateViewControllerWithIdentifier("VC1")
    let nc = UINavigationController(rootViewController: vc1)
    self.window?.rootViewController = nc

    return true
}

VC1.swift

class VC1: UIViewController 
{

    @IBAction func btnTapped(sender: AnyObject)
    {
        if let vc2 = self.storyboard?.instantiateViewControllerWithIdentifier("VC2")
        {
            self.navigationController?.pushViewController(vc2, animated: true)
        }
    }
}

VC2.swift

class VC2: UIViewController 
{

    @IBAction func btnTapped(sender: AnyObject)
    {
        if let vc1 = self.storyboard?.instantiateViewControllerWithIdentifier("VC1")
        {
            self.navigationController?.pushViewController(vc1, animated: true)
        }
    }
}

While I agree pushing VC2 in the navigation controller's stack is more common in iOS and probably a better UX, iOSFresher explicitly asked that VC1 be **replaced** with VC2. Not that VC2 be pushed on the stack. — Guillaume Algis, Oct 28 '15 at 21:15
if you really want to replace a view controller i would do it with self.navigationController?.setViewControllers([vc2], animated: true) instead of self.navigationController?.pushViewController(vc2, animated: true) — Manuel Blum, Oct 28 '15 at 22:16

iOS - Getting black view upon changing root view controller

1 Answers1