TabController addListener TabBar click double listener received

[120011676]

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget { // This widget is the root of your application. @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( // This is the theme of your application. // // Try running your application with "flutter run". You'll see the // application has a blue toolbar. Then, without quitting the app, try // changing the primarySwatch below to Colors.green and then invoke // "hot reload" (press "r" in the console where you ran "flutter run", // or simply save your changes to "hot reload" in a Flutter IDE). // Notice that the counter didn't reset back to zero; the application // is not restarted. primarySwatch: Colors.blue, // This makes the visual density adapt to the platform that you run // the app on. For desktop platforms, the controls will be smaller and // closer together (more dense) than on mobile platforms. visualDensity: VisualDensity.adaptivePlatformDensity, ), home: MyHomePage(title: 'Flutter Demo Home Page'), ); } }

class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key);

// This widget is the home page of your application. It is stateful, meaning // that it has a State object (defined below) that contains fields that affect // how it looks.

// This class is the configuration for the state. It holds the values (in this // case the title) provided by the parent (in this case the App widget) and // used by the build method of the State. Fields in a Widget subclass are // always marked "final".

final String title;

@override _MyHomePageState createState() => _MyHomePageState(); }

class _MyHomePageState extends State with SingleTickerProviderStateMixin { int _counter = 0; double _width = 200.0; final List tabs = ['直播', "拍照", "文档", "彩图"]; var _tabController; var defaultPage = 1;

void _incrementCounter() { setState(() { // This call to setState tells the Flutter framework that something has // changed in this State, which causes it to rerun the build method below // so that the display can reflect the updated values. If we changed // _counter without calling setState(), then the build method would not be // called again, and so nothing would appear to happen. _counter++; }); }

@override void initState() { super.initState(); _tabController = TabController( length: tabs.length, vsync: this, initialIndex: defaultPage); _tabController.addListener(() { print('----${_tabController.index}-----'); switch (_tabController.index) { case 0: break; case 1: break; case 2: break; } }); }

@override Widget build(BuildContext context) { // This method is rerun every time setState is called, for instance as done // by the _incrementCounter method above. // // The Flutter framework has been optimized to make rerunning build methods // fast, so that you can just rebuild anything that needs updating rather // than having to individually change instances of widgets. return Scaffold( appBar: AppBar( // Here we take the value from the MyHomePage object that was created by // the App.build method, and use it to set our appbar title. title: Text(widget.title), bottom: TabBar( //生成Tab菜单 controller: _tabController, tabs: tabs.map((e) => Tab(text: e)).toList()), ), body: Center( // Center is a layout widget. It takes a single child and positions it // in the middle of the parent. child: Column( // Column is also a layout widget. It takes a list of children and // arranges them vertically. By default, it sizes itself to fit its // children horizontally, and tries to be as tall as its parent. // // Invoke "debug painting" (press "p" in the console, choose the // "Toggle Debug Paint" action from the Flutter Inspector in Android // Studio, or the "Toggle Debug Paint" command in Visual Studio Code) // to see the wireframe for each widget. // // Column has various properties to control how it sizes itself and // how it positions its children. Here we use mainAxisAlignment to // center the children vertically; the main axis here is the vertical // axis because Columns are vertical (the cross axis would be // horizontal). mainAxisAlignment: MainAxisAlignment.center, children: [ Text( 'You have pushed the button this many times:', ), Text( '$_counter', style: Theme.of(context).textTheme.headline4, ), GestureDetector( child: Image.network( "http://a0.att.hudong.com/27/10/01300000324235124757108108752.jpg", width: _width, ), onScaleUpdate: (ScaleUpdateDetails details) { setState(() { _width = 200 * details.scale.clamp(0.7, 10.0); }); }) ], ), ), floatingActionButton: FloatingActionButton( onPressed: _incrementCounter, tooltip: 'Increment', child: Icon(Icons.add), ), // This trailing comma makes auto-formatting nicer for build methods. ); } }

I/flutter ( 7211): ----0----- I/flutter ( 7211): ----0-----

say@SaylideMacBook-Pro t % flutter upgrade Flutter is already up to date on channel stable Flutter 1.17.0 • channel stable • https://github.com/flutter/flutter.git Framework • revision e6b34c2b5c (10 days ago) • 2020-05-02 11:39:18 -0700 Engine • revision 540786dd51 Tools • Dart 2.8.1 say@SaylideMacBook-Pro t %

[jonahwilliams]

The Github issue tracker is for bugs and features requests for the Flutter SDK. Help and support questions like these are better suited for Q&A sites like StackOverflow or on one of the flutter community sites at https://flutter.dev/community .

[120011676]

@jonahwilliams Is this a TabBar bug? Do you need to reopen?

[120011676]

Other ways

_tabController.indexIsChanging

[github-actions[bot]]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.