Flutter：使用按钮在标签栏视图中更改当前标签 [英] Flutter: Changing the current tab in tab bar view using a button

问题描述

我正在创建一个应用，该应用的首页上包含一个标签栏。我希望能够使用我的 FloatingActionButton 导航到一个选项卡。另外，我想保留导航到该选项卡的默认方法，即通过在屏幕上滑动或单击该选项卡。

I am creating an app that contains a tab bar on its homepage. I want to be able to navigate to one of the tabs using my FloatingActionButton. In addition, I want to keep the default methods of navigating to that tab, i.e. by swiping on screen or by clicking the tab.

我还想知道如何链接该标签到其他按钮。

I also want to know how to link that tab to some other button.

这是我主页的屏幕截图。

Here is a screenshot of my homepage.

推荐答案

您需要获取 TabBar 控制器，并从按钮<$ c中调用其 animateTo（）方法$ c> onPressed（）句柄。

You need to get the TabBar controller and call its animateTo() method from the button onPressed() handle.

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      home: new MyTabbedPage(),
    );
  }
}

class MyTabbedPage extends StatefulWidget {
  const MyTabbedPage({Key key}) : super(key: key);

  @override
  _MyTabbedPageState createState() => new _MyTabbedPageState();
}

class _MyTabbedPageState extends State<MyTabbedPage> with SingleTickerProviderStateMixin {
  final List<Tab> myTabs = <Tab>[
    new Tab(text: 'LEFT'),
    new Tab(text: 'RIGHT'),
  ];

  TabController _tabController;

  @override
  void initState() {
    super.initState();
    _tabController = new TabController(vsync: this, length: myTabs.length);
  }

  @override
  void dispose() {
    _tabController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text("Tab demo"),
        bottom: new TabBar(
          controller: _tabController,
          tabs: myTabs,
        ),
      ),
      body: new TabBarView(
        controller: _tabController,
        children: myTabs.map((Tab tab) {
          return new Center(child: new Text(tab.text));
        }).toList(),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: () => _tabController.animateTo((_tabController.index + 1) % 2), // Switch tabs
        child: new Icon(Icons.swap_horiz),
      ),
    );
  }
}

如果使用 GlobalKey 用于 MyTabbedPageState ，您可以从任何位置获取控制器，因此可以调用 animateTo（）

If you use a GlobalKey for the MyTabbedPageState you can get the controller from any place, so you can call the animateTo() from any button.

class MyApp extends StatelessWidget {
  static final _myTabbedPageKey = new GlobalKey<_MyTabbedPageState>();

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      home: new MyTabbedPage(
        key: _myTabbedPageKey,
      ),
    );
  }
}

您可以在任何地方调用它：

You could call it from anywhere doing:

MyApp._myTabbedPageKey.currentState._tabController.animateTo（...）;

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