效果

实现

先将自动生成的main.dart里面的代码删除，

import 'package:flutter/material.dart';
import 'package:flutter_guohe/pages/main.dart';

void main() {
  runApp(new Guohe());
}

创建app.dart作为首页的页面文件

class Guohe extends StatefulWidget {
  @override
  GuoheState createState() => new GuoheState();
}

class GuoheState extends State<Guohe> {
  @override
  Widget build(BuildContext context) {
  
  }
}

创建today.dart、kb.dart、playground.dart三个页面文件作为tabview的填充文件，这里用playground.dart为例。

import 'package:flutter/material.dart';

class Playground extends StatefulWidget {
  @override
  PlaygroundState createState() => new PlaygroundState();
}

class PlaygroundState extends State<Playground> {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text("操场"),
          backgroundColor: Color.fromARGB(255, 119, 136, 213), //设置appbar背景颜色
          centerTitle: true, //设置标题是否局中
        ),
        body: new Center(
          child: new Text('操场'),
        ),
      ),
    );
  }
}

app.dart的完整代码

/**
 * APP的主入口文件
 */

import 'package:flutter/material.dart';

import 'package:flutter_guohe/pages/main/today.dart';
import 'package:flutter_guohe/pages/main/playground.dart';
import 'package:flutter_guohe/pages/main/kb.dart';
import 'package:flutter_guohe/pages/main/leftmenu.dart';

import 'package:flutter_guohe/common/eventBus.dart';

//果核的主界面
class Guohe extends StatefulWidget {
  @override
  GuoheState createState() => new GuoheState();
}

class GuoheState extends State<Guohe> with SingleTickerProviderStateMixin {
  TabController controller;

  @override
  void initState() {
    controller = new TabController(length: 3, vsync: this);
  }

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

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new Scaffold(
        drawer: new LeftMenu(),
        body: new TabBarView(
          controller: controller,
          children: <Widget>[
            new Today(),
            new Kb(),
            new Playground(),
          ],
        ),
        bottomNavigationBar: new Material(
          color: Colors.white,
          child: new TabBar(
            controller: controller,
            labelColor: Colors.deepPurpleAccent,
            unselectedLabelColor: Colors.black26,
            tabs: <Widget>[
              new Tab(
                text: "今日",
                icon: new Icon(Icons.brightness_5),
              ),
              new Tab(
                text: "课表",
                icon: new Icon(Icons.map),
              ),
              new Tab(
                text: "操场",
                icon: new Icon(Icons.directions_run),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

其中

labelColor: Colors.deepPurpleAccent,
unselectedLabelColor: Colors.black26,

第一个属性是控制标签颜色，这里我选了紫色，第二个属性是未选中标签时的颜色。