Navigation Controller in iOS

Properties of NavigationController

There are several properties that the UINavigationController class provides us to use the different features of this class.

Here we have discussed some of its important properties rest you can find them on the official site of developer.apple.

Methods of NavigationController

Apart from the properties, this class also provides us with a number of methods.

Example on Navigation Controller

Here we discuss an example, we create two screens one is the home screen, and another contains the color which we send through the home screen.

Class to make the navigations.

Code:

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        ...
        let navigationController = UINavigationController(rootViewController: pickColorVC)


        window = UIWindow(frame: UIScreen.main.bounds)
        if let window = window {
          window.rootViewController = navigationController
          window.makeKeyAndVisible()
        }
        return true
    }
    ...
}

Explanation: In this example, we create a navigation controller and give it the color picker view controller as its root view controller. The navigation controller is also assigned as the window object's root view controller.

This class applies the navigation.

Code:

class ColorPickerViewController: UIViewController {


    @IBAction func didTapRedButton(sender: Any) {
        pushViewController(title: "Red", color: UIColor.red)
    }


    @IBAction func didTapBlueButton(sender: Any) {
        pushViewController(title: "Blue", color: UIColor.blue)
    }


    private func pushViewController(title: String, color: UIColor) {
        let vc = UIViewController()
        vc.view.backgroundColor = color
        vc.title = title
        self.navigationController?.pushViewController(vc, animated: true)
    }
}

Explanation: When a button is pressed, we create a new view controller and put it onto the navigation stack using pushViewController.

Output:

Frequently Asked Questions

What is the UIApplicationDelegate?

UIApplicationDelegate is a protocol that your app must implement to be notified of user events like app launch, app switching to the background or foreground, app termination, or the opening of a push notification.

What is the UIResponder?

In a nutshell, UIResponder instances are objects that can handle and respond to various events. UIResponders are used by UIView, UIViewController, UIWindow, UIApplication, and UIApplicationDelegate in iOS.  

What is the UIColorPickerViewController?

To give your app additional control over the process, the UIColorPickerViewController logs user involvement using a UIColorWell. For example, you can alter supportsAlpha to false to hide the alpha slider and only allow opaque colors by setting the initial selectedColor.

Conclusion

In this article, we have extensively discussed the Navigation Controller in iOS. We discussed how this navigation works and also one simple example to clarify the concept.

We hope that this blog has helped you enhance your knowledge regarding the Navigation Controller. Do check out the awesome content on the Coding Ninjas Website, Android Development, Coding Ninjas Studio Problems, Coding Ninjas Studio Interview Bundle, Coding Ninjas Studio Interview Experiences, Coding Ninjas Courses, Coding Ninjas Studio Contests, and Coding Ninjas Studio Test Series. Do upvote our blog to help other ninjas grow. 

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