UITabBarController showing only the first tab

Question

I am reasking this because the question in UITabbarController showing only first tab was not answered ... I don't understand why my UITabBarController is showing just the first tab .

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        self.window = UIWindow(frame: UIScreen.main.bounds)
        self.window?.backgroundColor = UIColor.darkGray
        self.window?.makeKeyAndVisible()
        let tab = UITabBarController()
        let v1 = VC1(nibName: "View1", bundle: nil)
        let v2 = VC2(nibName: "View2", bundle: nil)
        let v3 = VC3(nibName: "View3", bundle: nil)
        let myViews = [v1,v2,v3]
        tab.viewControllers = myViews
        self.window?.rootViewController = tab 
        return true
    }

}

VC1 Code:

class VC1: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        print("view 1 will load")
        self.title = "View 1"
        // Do any additional setup after loading the view.
    }

}

class VC2:

class VC1: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        print("view 2 will load")
        self.title = "View 2"
        // Do any additional setup after loading the view.
    }

}

VC3:

class VC1: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        print("view 3 will load")
        self.title = "View 3"
        // Do any additional setup after loading the view.
    }

}

I think this is a tested and proven way to create tabs but it doesn't seem to work, here's the result screenshot

score 3 · Answer 1 · answered Dec 10 '16 at 01:16

UITabBarController uses the title from each view controller to create the labels that appear on-screen. The problem here is that your view controllers don't have any value for the title property until viewDidLoad is called, which is too late.

You should be setting the title property during initialization; initWithNibName:bundle: would be a good place for this.

cromanelli · Accepted Answer · 2016-12-17T12:36:16.680

I found a cleaner way to implement this , View Controller's title is a property and can be set right after it's instanciated

So the updated code looks like :

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        self.window = UIWindow(frame: UIScreen.main.bounds)
        self.window?.backgroundColor = UIColor.darkGray
        self.window?.makeKeyAndVisible()
        let tab = UITabBarController()
        let v1 = VC1(nibName: "View1", bundle: nil)
        let v2 = VC2(nibName: "View2", bundle: nil)
        let v3 = VC3(nibName: "View3", bundle: nil)
        v1.title = "View 1"
        v2.title = "View 2"
        v3.title = "View 3"
        let myViews = [v1,v2,v3]
        tab.setViewControllers(myViews, animated: false)
        self.window?.rootViewController = tab 
        return true
    }

}

and the screenshot is :

UITabBarController showing only the first tab

2 Answers2