How to set viewcontroller of UITabbarItem to default viewcontroller when switching tabs? - ios

Question

I have a UITabBarController. It has 4 tabBarItem.
Suppose I'm at 1st tabBarItem defaultViewController(1) and I
went to another ViewController(2) which is shown after some
actions in first defaultViewController(1).
Then I switched to 2nd tabBarItem defaultViewcontroller(2).
Again I switched back to 1st tabBarItem, it shows ViewController(2).
I want to show defaultViewController(1). How can I achieve this using swift 4.
defaultViewController(1) and defaultViewController(2) are the default ViewController for 1st and 2nd TabBarItem respectively.***

Answer 1

Let's say you have UINavigationController inside each tab of UITabBarController, and defaultViewController(1) is the rootViewController of your first tab, inside that there is a button that navigate to ViewController(2).
For this first of all, let's create generic solution. Create UIApplication Extension like this,
extension UIApplication {
class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
if let navigationController = controller as? UINavigationController {
return topViewController(controller: navigationController.visibleViewController)
}
return controller
}
}
Implement UITabBarControllerDelegate in AppDelegate and do below code,
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
if tabBarController.selectedIndex == 0 {
UIApplication.topViewController()?.navigationController?.popToRootViewController(animated: false)
}
}
In above code, I have taken tabBarController.selectedIndex to 0, you can make it different depending on your requirement.
Let me know in case of any queries.

Answer 2

Extend a subclass of UITabbarController and use it as your tabbar's class. In that implement UITabBarControllerDelegate, didSelect and use popToRootViewController to pop to your defaultViewController.
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController){
if viewController is UINavigationController {
//when you have `UINavigationController`
let rootNavigationController = viewController as! UINavigationController
rootNavigationController.popToRootViewController(animated: false)
} else {
//when you don't have `UINavigationController` then dismiss all viewcontroller that was presented.
let rootViewController = viewController
if rootViewController.presentingViewController != nil {
rootViewController.dismiss(animated: false, completion: nil)
}
}
}
Note: add self.delegate = self to conform the protocol inside viewDidLoad method.