Fix TabBarView with no animation not navigating (#110985)

packages/flutter/lib/src/material/tabs.dart

@@ -1532,13 +1532,14 @@ class _TabBarViewState extends State<TabBarView> {
 
     if (duration == Duration.zero) {
       _pageController.jumpToPage(_currentIndex!);
-      return Future<void>.value();
-    }
+    } else {
+      await _pageController.animateToPage(_currentIndex!, duration: duration, curve: Curves.ease);
 
-    await _pageController.animateToPage(_currentIndex!, duration: duration, curve: Curves.ease);
-    if (!mounted) {
-      return Future<void>.value();
+      if (!mounted) {
+        return Future<void>.value();
+      }
     }
+
     setState(() {
       _warpUnderwayCount -= 1;
       if (widget.children != _children) {

packages/flutter/test/material/tabs_test.dart

@@ -1354,6 +1354,108 @@ void main() {
     expect(position.pixels, 800);
   });
 
+  testWidgets('TabBarView skips animation when disabled in controller - skip tabs twice', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/110970
+    final List<String> tabs = <String>['A', 'B', 'C'];
+    final TabController tabController = TabController(
+      vsync: const TestVSync(),
+      length: tabs.length,
+      animationDuration: Duration.zero,
+    );
+    await tester.pumpWidget(boilerplate(
+      child: Column(
+        children: <Widget>[
+          TabBar(
+            tabs: tabs.map<Widget>((String tab) => Tab(text: tab)).toList(),
+            controller: tabController,
+          ),
+          SizedBox(
+            width: 400.0,
+            height: 400.0,
+            child: TabBarView(
+              controller: tabController,
+              children: const <Widget>[
+                Center(child: Text('0')),
+                Center(child: Text('1')),
+                Center(child: Text('2')),
+              ],
+            ),
+          ),
+        ],
+      ),
+    ));
+
+    expect(tabController.index, 0);
+
+    final PageView pageView = tester.widget(find.byType(PageView));
+    final PageController pageController = pageView.controller;
+    final ScrollPosition position = pageController.position;
+
+    // The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
+    // page 1 is at 400.0, page 2 is at 800.0.
+    expect(position.pixels, 0);
+    await tester.tap(find.text('C'));
+    await tester.pump();
+    expect(position.pixels, 800);
+
+    await tester.tap(find.text('A'));
+    await tester.pump();
+    expect(position.pixels, 0);
+  });
+
+  testWidgets('TabBarView skips animation when disabled in controller - skip tabs followed by single tab navigation', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/110970
+    final List<String> tabs = <String>['A', 'B', 'C'];
+    final TabController tabController = TabController(
+      vsync: const TestVSync(),
+      length: tabs.length,
+      animationDuration: Duration.zero,
+    );
+    await tester.pumpWidget(boilerplate(
+      child: Column(
+        children: <Widget>[
+          TabBar(
+            tabs: tabs.map<Widget>((String tab) => Tab(text: tab)).toList(),
+            controller: tabController,
+          ),
+          SizedBox(
+            width: 400.0,
+            height: 400.0,
+            child: TabBarView(
+              controller: tabController,
+              children: const <Widget>[
+                Center(child: Text('0')),
+                Center(child: Text('1')),
+                Center(child: Text('2')),
+              ],
+            ),
+          ),
+        ],
+      ),
+    ));
+
+    expect(tabController.index, 0);
+
+    final PageView pageView = tester.widget(find.byType(PageView));
+    final PageController pageController = pageView.controller;
+    final ScrollPosition position = pageController.position;
+
+    // The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
+    // page 1 is at 400.0, page 2 is at 800.0.
+    expect(position.pixels, 0);
+    await tester.tap(find.text('C'));
+    await tester.pump();
+    expect(position.pixels, 800);
+
+    await tester.tap(find.text('B'));
+    await tester.pump();
+    expect(position.pixels, 400);
+
+    await tester.tap(find.text('A'));
+    await tester.pump();
+    expect(position.pixels, 0);
+  });
+
   testWidgets('TabBarView skips animation when disabled in controller - two tabs', (WidgetTester tester) async {
     final List<String> tabs = <String>['A', 'B'];
     final TabController tabController = TabController(