How to show different ViewControllers when tapping on tabBar in swift - ios

Question

I have three viewControllers and two of them connected to a tabBarController. So app should show one of the two vc’s depending Bool value when tapping on tabBar item here is my storyboard
import UIKit
class TabBarController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
let userLoggedIn: Bool!
if tabBarController.selectedIndex == 1{
if userLoggedIn == true{
// show firstVC
}else{
// show secondVC
}
}
}
}

Answer 1

You can use childViewController with the parent is ViewController fromStoryboard.
override func viewDidLoad() {
super.viewDidLoad()
///add two ChildVC here, hide 1 ifneeded
}
When click to this tab you check userLoggedIn.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if userLoggedIn == true {
/// show first childVC
/// hide second childVC
} else {
/// hide first childVC
/// show second childVC
}
}
You can check demo: Demo

Answer 2

Simply add .overCurrentContext to modalPresentationStyle in your viewDidLoad like this.
let newVC = self.storyboard?.instantiateViewController(withIdentifier:"secondVC")
newVC?.modalPresentationStyle = .overCurrentContext
self.present(newVC!, animated: false, completion: nil)

Answer 3

Simply set the viewController list when the userLoggedIn variable is modified (assuming userLoggedIn is TabBarCOntroller instance variable) :
class TabBarC: UITabBarController {
#IBOutlet var firstVC : FirstViewController!
#IBOutlet var secondVC : SecondViewController!
#IBOutlet var thirdVC : ThirdViewController!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
for vc in self.viewControllers! {
if let fv = vc as? FirstViewController {
firstVC = fv
} else if let fv = vc as? SecondViewController {
secondVC = fv
} else if let fv = vc as? ThirdViewController {
thirdVC = fv
}
}
}
var userLoggedIn : Bool = false {
didSet {
if userLoggedIn {
self.viewControllers = [firstVC, thirdVC]
} else {
self.viewControllers = [secondVC, thirdVC]
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self. userLoggedIn = false
}
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
if item.tag == 3 { // For purpose of test i set tag for 3 VC to 1 for firsttVC, 2 for secondVC, 3 for thirdVC
// for test : change login value each time thirdVC is selected
userLoggedIn = ! userLoggedIn
}
}
So each time from anywhere in your code you setup userLoggedIn, the tabor show the wanted tab bar items.
The 3 VC are added to the tabbar in the stpryboard.
When selecting thirdVC, the first tab bar item changes between one and two