一款完美的App怎么少得了TabBar

image.png

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(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'flutter的底部导航'),
    );
  }
}

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  int _tabIndex = 0;
  TabController _controller;
  List<Tab> _tabs = <Tab>[
    Tab(
      text: '最新动态',
    ),
    Tab(
      text: '成员列表',
    ),
    Tab(
      text: '社团活动',
    ),
  ];

  @override
  void initState() {
    super.initState();

    //initialIndex初始选中第几个
    _controller = TabController(
      initialIndex: 2,
      length: _tabs.length,
      vsync: this,
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        centerTitle: true,
        bottom: TabBar(
          isScrollable: true,
          tabs: _tabs,
          controller: _controller,
        ),
      ),
      body: TabBarView(
        controller: _controller,
        children: _tabs
            .map(
              (Tab tab) => Container(
                child: Card(
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadiusDirectional.circular(20),
                  ),
                  clipBehavior: Clip.antiAlias,
                  child: Image.asset(
                    "images/big.jpg",
                    width: double.maxFinite,
                  ),
                ),
              ),
            )
            .toList(),
      ),
      bottomNavigationBar: BottomNavigationBar(
        items: <BottomNavigationBarItem>[
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            title: Text('home'),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.school),
            title: Text('school'),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.person),
            title: Text('person'),
          ),
        ],
        type: BottomNavigationBarType.fixed,
        currentIndex: _tabIndex,
        onTap: (index) {
          setState(() {
            _tabIndex = index;
          });
        },
      ),
    );
  }
}

定制TabBar

/**
    const TabBar({
    Key key,
    @required this.tabs,//显示的标签内容，一般使用Tab对象,也可以是其他的Widget
    this.controller,//TabController对象
    this.isScrollable = false,//是否可滚动
    this.indicatorColor,//指示器颜色
    this.indicatorWeight = 2.0,//指示器高度
    this.indicatorPadding = EdgeInsets.zero,//底部指示器的Padding
    this.indicator,//指示器decoration，例如边框等
    this.indicatorSize,//指示器大小计算方式，TabBarIndicatorSize.label跟文字等宽,TabBarIndicatorSize.tab跟每个tab等宽
    this.labelColor,//选中label颜色
    this.labelStyle,//选中label的Style
    this.labelPadding,//每个label的padding值
    this.unselectedLabelColor,//未选中label颜色
    this.unselectedLabelStyle,//未选中label的Style
    }) : assert(tabs != null),
    assert(isScrollable != null),
    assert(indicator != null || (indicatorWeight != null && indicatorWeight > 0.0)),
    assert(indicator != null || (indicatorPadding != null)),
    super(key: key);
 */