Selected Index on Tab Bar not working on Swift

Question

I want to change the default selected view controller of a UITabBar / UITabBarController via selectedIndex.

I tried other solutions I saw in other threads, like changing it in the AppDelegate or in ViewDidAppear like this:

class MainTabBarController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        setupTabBar()
    }


    override func viewDidAppear(_ animated: Bool) {
        // this is the attempt to set the selected index that doesn't work 
        self.tabBarController?.selectedIndex = 2
    }

    func setupTabBar(){
        let vc1 = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "mainvc")
        let vc2 = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "secondvc")
        let vc3 = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "thirdvc")
        let FirstController = UINavigationController(rootViewController: vc1)
        let SecondController = UINavigationController(rootViewController: vc2)
        let ThirdController = UINavigationController(rootViewController: vc3)

        viewControllers = [FirstController, SecondController, ThirdController]
    }

}

Nothing worked so far, and it always shows the selected index = 0.

I set the tab bar view controller as the initial view controller in the Main storyboard. Should I be doing this in the AppDelegate instead?

score 4 · Accepted Answer · answered Jun 05 '19 at 05:40

You are saying that

class MainTabBarController: UITabBarController {

so self refers to a UITabBarController, but you are setting the selected index of tabBarController of self:

self.tabBarController?.selectedIndex = 2

There are no tab bar controllers embedded in self. self itself is a tab bar controller! You can just set self.selectedIndex:

self.selectedIndex = 2

Also, you should do that in viewDidLoad instead of viewDidAppear, because viewDidAppear can happen many times (every time some modal controller is dismissed for example). viewDidLoad will only be called once.

Selected Index on Tab Bar not working on Swift

1 Answers1