dart笔记2:顶部tabbar

import 'package:flutter/material.dart';

class TabbedAppBarSample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: DefaultTabController(
      length: choices.length,
      child: Scaffold(
        appBar: AppBar(
          title: Text('Tabbed AppBar'),
          bottom: TabBar(
            isScrollable: true,
            tabs: choices.map((Choice choice) {
              return Tab(text: choice.title, icon: Icon(choice.icon));
            }).toList(),
          ),
        ),
        body: TabBarView(
            children: choices.map((Choice choice) {
          return Padding(
            padding: EdgeInsets.all(16.0),
            child: ChoiceCard(choice: choice),
          );
        }).toList()),
      ),
    ));
  }
}

class Choice {
  const Choice({this.title, this.icon});
  final String title;
  final IconData icon;
}

const List<Choice> choices = const <Choice>[
  const Choice(title: 'CAR', icon: Icons.directions_car),
  const Choice(title: 'BICYCLE', icon: Icons.directions_bike),
  const Choice(title: 'BOAT', icon: Icons.directions_boat),
  const Choice(title: 'BUS', icon: Icons.directions_bus),
  const Choice(title: 'TRAIN', icon: Icons.directions_railway),
  const Choice(title: 'WALK', icon: Icons.directions_walk)
];

class ChoiceCard extends StatelessWidget {
  const ChoiceCard({Key key, this.choice}) : super(key: key);

  final Choice choice;

  @override
  Widget build(BuildContext context) {
    final TextStyle textStyle = Theme.of(context).textTheme.bodyText1;
    return Card(
      color: Colors.white,
      child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Icon(
              choice.icon,
              size: 128.0,
              color: textStyle.color,
            ),
            Text(
              choice.title,
              style: textStyle,
            )
          ],
        ),
      ),
    );
  }
}

void main() => runApp(TabbedAppBarSample())