Trouble with UITabBarController and Child View Controller Transitions in iOS 16
I recently switched to I'm learning this framework and After trying multiple solutions online, I still can't figure this out. I'm collaborating on a project where I tried several approaches but none seem to work. I am working on an iOS app using Swift and UIKit, and I’m encountering an issue with transitions between child view controllers within a UITabBarController. When I switch tabs, the new view controller does not appear with the expected animated transition. Instead, it just pops up abruptly, which makes the user experience feel jarring. Here’s a simplified version of my setup: ```swift class MainTabBarController: UITabBarController { override func viewDidLoad() { super.viewDidLoad() let firstVC = FirstViewController() let secondVC = SecondViewController() self.viewControllers = [firstVC, secondVC] } } ``` In both `FirstViewController` and `SecondViewController`, I am using standard navigation controllers and presenting a modal view on a button tap. The transition style for my tab bar controller is set to default, but I’ve tried setting it to `UIView.AnimationOptions.transitionFlipFromLeft`, and that didn't seem to help either. I have also verified that the child view controllers' view lifecycle methods are being called correctly: ```swift override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) print("View will appear") } ``` However, when I switch tabs, the log shows that the viewWillAppear is called for the newly selected tab, but visually, there’s no smooth transition. Additionally, I tried overriding the `tabBar(_:didSelect:)` method to add a custom transition but ran into issues with retaining the view hierarchy: ```swift func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) { guard let index = tabBar.items?.firstIndex(of: item) else { return } let selectedVC = viewControllers?[index] as? UIViewController selectedVC?.viewWillAppear(true) UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve) { self.selectedViewController = selectedVC } } ``` However, this results in a flash of the previous view controller's content before transitioning. I’ve also checked the `UIViewController` containment documentation to ensure I’m using the containment model correctly, but I’m still missing something. Has anyone encountered similar issues with transitions in UITabBarController? What am I doing wrong, or is there a better approach I should consider for smooth transitions? Any insights or examples would be greatly appreciated! My development environment is Linux. My development environment is Linux. What's the best practice here? For reference, this is a production application. I'm working with Swift in a Docker container on Debian. Could someone point me to the right documentation? This is my first time working with Swift stable. What would be the recommended way to handle this? What's the correct way to implement this?