[teddyxfire1992]

PR Description

Closes #593.

The fix was proposed by @pawarren in the issue; this PR applies it and adds a changeset.

hideTabBar is a @ViewBuilder that branched on flag, so toggling tabBarHidden swapped the _ConditionalContent case and changed the view's structural identity. SwiftUI then rebuilt the tab content, which dismissed sheets presented from inside the tab and dropped text input focus. A common trigger is hiding the tab bar while the keyboard is up: focusing a field raises the keyboard, the app hides the tab bar, and the field loses focus and the sheet is dismissed.

This branches only on #available, which is constant at runtime, and passes the flag as the value: .toolbar(flag ? .hidden : .automatic, for: .tabBar). .automatic is the default visibility, so the visible tab bar behaves as before. The pre-iOS 16 fallback is unchanged.

On iOS 18+ (NewTabView) the modifier wraps each tab's content. On older iOS (LegacyTabView) it wraps the whole TabView, so the fix covers both.

How to test?

1. Create an app with react-native-bottom-tabs and @expo/ui. In a tab, render a BottomSheet containing a TextField.
2. Hide the tab bar while the keyboard is up:

   useEffect(() => {
     const show = Keyboard.addListener('keyboardWillShow', () => setTabBarHidden(true))
     const hide = Keyboard.addListener('keyboardWillHide', () => setTabBarHidden(false))
     return () => {
       show.remove()
       hide.remove()
     }
   }, [])

3. Open the sheet and tap the text field.
4. Before: the keyboard closes at once, typing does nothing, and the sheet's onDismiss fires (2–3 times) before it is presented again.
5. After: the field keeps focus, typing works, onDismiss does not fire, and the tab bar hides while the keyboard is up.

The same issue shows without a sheet: a plain TextInput in a tab loses focus as soon as the keyboard hides the tab bar.

Verified with agent-device in a fresh Expo SDK 57 app (React Native 0.86.3, @expo/ui 57.0.26, react-native-bottom-tabs 1.5.0 patched in place), plus the example app's Tab Bar Hidden screen with a TextInput.

Recordings

iOS 26 before

before-ios26.mov

iOS 26 after

after-ios26.mov

iOS 17 before

before-ios17.mov

iOS 17 after

after-ios17.mov