Flutter - listening to updates in TabBar when using DefaultTabController

tab_controller_demo.dart

// listening to updates in TabBar when using DefaultTabController.
import 'package:flutter/material.dart';

void main() {
  runApp(TabControllerDemo());
}

class TabControllerDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
          length: 3,
          child: Builder(builder: (BuildContext context) {
            final TabController controller = DefaultTabController.of(context)!;
            controller.addListener(() {
              if (!controller.indexIsChanging) {
                print(controller.index);
                // add code to be executed on TabBar change
              }
            });
            return Scaffold(
              appBar: AppBar(
                bottom: const TabBar(
                  tabs: [
                    Tab(text: "Tab 0"),
                    Tab(text: "Tab 1"),
                    Tab(text: "Tab 2"),
                  ],
                ),
                title: const Text('Tabs Demo'),
              ),
              body: const TabBarView(
                children: [
                  Center(child: Text('View 0')),
                  Center(child: Text('View 1')),
                  Center(child: Text('View 2')),
                ],
              ),
            );
          })),
    );
  }
}