Change the TabController should make both TabBar and TabBarView return to the initial index (#94339)
diff --git a/packages/flutter/lib/src/material/tabs.dart b/packages/flutter/lib/src/material/tabs.dart
index ea0aac1..fe3483c 100644
--- a/packages/flutter/lib/src/material/tabs.dart
+++ b/packages/flutter/lib/src/material/tabs.dart
@@ -1348,15 +1348,18 @@
void didChangeDependencies() {
super.didChangeDependencies();
_updateTabController();
- _currentIndex = _controller?.index;
- _pageController = PageController(initialPage: _currentIndex ?? 0);
+ _currentIndex = _controller!.index;
+ _pageController = PageController(initialPage: _currentIndex!);
}
@override
void didUpdateWidget(TabBarView oldWidget) {
super.didUpdateWidget(oldWidget);
- if (widget.controller != oldWidget.controller)
+ if (widget.controller != oldWidget.controller) {
_updateTabController();
+ _currentIndex = _controller!.index;
+ _pageController.jumpToPage(_currentIndex!);
+ }
if (widget.children != oldWidget.children && _warpUnderwayCount == 0)
_updateChildren();
}
diff --git a/packages/flutter/test/material/tabs_test.dart b/packages/flutter/test/material/tabs_test.dart
index 7e0adf8..1311ce1 100644
--- a/packages/flutter/test/material/tabs_test.dart
+++ b/packages/flutter/test/material/tabs_test.dart
@@ -4183,6 +4183,79 @@
semantics.dispose();
});
+
+ testWidgets('Change the TabController should make both TabBar and TabBarView return to the initial index.', (WidgetTester tester) async {
+ // This is a regression test for https://github.com/flutter/flutter/issues/93237
+
+ Widget buildFrame(TabController controller, bool showLast) {
+ return boilerplate(
+ child: Column(
+ children: <Widget>[
+ TabBar(
+ controller: controller,
+ tabs: <Tab>[
+ const Tab(text: 'one'),
+ const Tab(text: 'two'),
+ if (showLast) const Tab(text: 'three'),
+ ],
+ ),
+ Flexible(
+ child: TabBarView(
+ controller: controller,
+ children: <Widget>[
+ const Text('PAGE1'),
+ const Text('PAGE2'),
+ if (showLast) const Text('PAGE3'),
+ ],
+ ),
+ ),
+ ],
+ ),
+ );
+ }
+
+ final TabController controller1 = TabController(
+ vsync: const TestVSync(),
+ length: 3,
+ );
+
+ final TabController controller2 = TabController(
+ vsync: const TestVSync(),
+ length: 2,
+ );
+
+ final TabController controller3 = TabController(
+ vsync: const TestVSync(),
+ length: 3,
+ );
+
+ await tester.pumpWidget(buildFrame(controller1, true));
+ final PageView pageView = tester.widget(find.byType(PageView));
+ final PageController pageController = pageView.controller;
+
+ await tester.tap(find.text('three'));
+ await tester.pumpAndSettle();
+ expect(controller1.index, 2);
+ expect(pageController.page, 2);
+
+ // Change TabController from 3 items to 2.
+ await tester.pumpWidget(buildFrame(controller2, false));
+ await tester.pumpAndSettle();
+ expect(controller2.index, 0);
+ expect(pageController.page, 0);
+
+ // Change TabController from 2 items to 3.
+ await tester.pumpWidget(buildFrame(controller3, true));
+ await tester.pumpAndSettle();
+ expect(controller3.index, 0);
+ expect(pageController.page, 0);
+
+ await tester.tap(find.text('three'));
+ await tester.pumpAndSettle();
+
+ expect(controller3.index, 2);
+ expect(pageController.page, 2);
+ });
}
class KeepAliveInk extends StatefulWidget {
