UITabBarController
|
|
VC_Tab1 --------------------------- VC_Tab2
| |
| |
VC_Tab1_Child VC_Tab2_Child
|
(HeaderView)
|
(MyButton)
The structure of the view controllers and views in the project is as described above.
<case 1>
self.navigationController?.popToRootViewController(animated: false)
tabBarController.selectedIndex = 1
When popToRootViewController(animated: false) is called in VC_Tab1_Child, followed by setting the tab controller’s selectedIndex = 1, the following results are observed:
viewWillAppear(_:), <VC_Tab2_Child>
deinit, <VC_Tab1_Child>
viewDidAppear(_:), <VC_Tab2_Child>
The originally expected results are as follows
viewWillDisappear(_:), <VC_Tab1_Child>
viewDidDisappear(_:), <VC_Tab1_Child>
deinit, <VC_Tab1_Child>
deinit, <HeaderView>
deinit, <MyButton>
headerView.backButton.rx.tap -> Event completed
headerView.backButton.rx.tap -> isDisposed
viewWillAppear(_:), <VC_Tab2_Child>
viewDidAppear(_:), <VC_Tab2_Child>
The HeaderView belonging to VC_Tab1_Child was not deallocated, and the resources associated with that view were also not released. Similarly, VC_Tab1_Child.viewWillDisappear and VC_Tab1_Child.didDisappear were not called.
<case 2>
self.navigationController?.popToRootViewController(animated: false)
DispatchQueue.main.async {
tabBarController.selectedIndex = 1
}
After performing the pop operation as shown in the code and waiting for a short period before testing, the expected results were generally achieved. (However, rarely, the results were similar to those observed when called without async.)”
<case 3>
self.navigationController?.popToRootViewController(animated: false)
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
tabBarController.selectedIndex = 1
}
When a sufficient delay was ensured as described above, the expected results were achieved 100% of the time.”
The abnormal behavior is more pronounced in iOS versions prior to 18 and varies depending on the iOS version.
I couldn’t find any documentation explaining the unexpected behavior shown in the results above. What could be the cause? The simulation code is provided below.