Navigation bar not showing iOS swift

问题:

I am having multiple view controller in my application. I want to hide navigationbar in my first view controller. So I use the following code to hide the navigation bar

navigationController?.setNavigationBarHidden(navigationController?.navigationBarHidden == false, animated: true);

Now I want to add navigation bar in some other viewController but, my navigation bar not visible in that viewcontroller. Why it is happening?

My storyboard showing the navigation bar but once I try to run my application it is gone.

If I hide navigation bar from one view controller then we can't use navigation controller, Is it so? I hope I am wrong. Then what are the reasons for navigation bar not shown?

EDIT:

Also I want my view controller in portrait mode only. So I did the following Is that causing the issue?

extension UINavigationController{
    public override func shouldAutorotate() -> Bool {
        if (UIDevice.currentDevice().orientation == UIDeviceOrientation.LandscapeLeft ||
            UIDevice.currentDevice().orientation == UIDeviceOrientation.LandscapeRight ||
            UIDevice.currentDevice().orientation == UIDeviceOrientation.Unknown) {
                return false
        }
        else {
            return true
        }
    }

    public override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
        return [UIInterfaceOrientationMask.Portrait ,UIInterfaceOrientationMask.PortraitUpsideDown]
    }


}

Edit 1:

I am using following code to move from one view controller not link from the storyboard. Is that causing issue now?

 let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let secondViewController = storyboard.instantiateViewControllerWithIdentifier("HomeVC")
        presentViewController(secondViewController, animated: false, completion: nil)

Edit 2:

Please check my following screenshots. Which are my settings for secondview controller

Edit 3:

Here is my navigation controller attribute inspector

回答1:

Navigation Controller is a controller, which has stack of view controllers. So if you have something like this:

NAV -> A -> (segue) B

Even if you'll hide navigation bar you still should be able to make segues. Also can't you just unhide navigation bar in second (B) view controller in viewWillAppear? And in first the same way hide it on viewWillAppear.

edit: Final solution to the problem: Use:

 let controller = storyboard.instantiateViewControllerWithIdentifier("HomeVC")
 self.navigationController!.pushViewController(controller) 

instead of:

let secondViewController = storyboard.instantiateViewControllerWithIdentifier("HomeVC")
presentViewController(secondViewController, animated: false, completion: nil)

Because pushViewController will add secondViewController to its stack. presentViewController was replacing your navigation controller that's why you couldn't see navigation bar.

回答2:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Hide the navigation bar on the this view controller
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    // Show the navigation bar on other view controllers
    self.navigationController?.setNavigationBarHidden(false, animated: animated)
}

回答3:

in viewDidLoad method of the view controller in which you don't want to show navigation bar add the line

navigationController.navigationBarHidden = true

you are presently hiding in all view controllers

Edit: You are presenting view controller instead it should be

self.navigationController!.pushViewController(controller) 

回答4:

I am having same requirement in my swift project.

this is how I have handled Navigation bar

Make sure your first screen is embedded into Navigation controller

example we have two screens A and B

In screen A you need to hide navigation bar in viewWillAppear

override func viewWillAppear(animated: Bool)
    {
         super.viewWillAppear(animated)

        //hide navigation for screen A
        self.navigationController?.navigationBarHidden = true
    }

for enabling Navigation in screen B you need to add below code in screen A

override func prepareForSegue(segue: (UIStoryboardSegue!), sender: AnyObject!)
    {
        if (segue.identifier == "screen B's segue identifier here")
        {
           //enable navigation for screen B       
            navigationController?.setNavigationBarHidden(navigationController?.navigationBarHidden == false, animated: true)
        }

    }

Using above style, I can enable or disable navigation bar for specific screen, whenever I want

回答5:

If you need to have this navigation bar hidden only in this controller, the best way is to show it in viewWillDisappear() and hide in viewWillAppear().

回答6:

do like in viewcontroller based hidden using Swift 4.0

To hide navigationController in viewWillAppear

override func viewWillAppear(animated: Bool) {
     super.viewWillAppear(animated)
    self.navigationController?.isNavigationBarHidden = true
}

To unhide navigationController in viewWillDisappear

override func viewWillDisappear(animated: Bool)
{
    super.viewWillDisappear(animated)
    self.navigationController?.isNavigationBarHidden = false
}

回答7:

It's too late to reply and there are other good answers but I would like to share what worked for me.

let controller = self.storyboard?.instantiateViewControllerWithIdentifier("HomeVC")
    self.navigationController!.pushViewController(controller!, animated:true)