Flutter布局-BottomNavigationBar组件

BottomNavigationBar是底部导航条，可以让我们定义底部tab切换，BottomNavigationBar是Scaffold组件的参数。

BottomNavigationBar组件的常用属性

属性名	说明
items	List<BottomNavigationBar> 底部导航按钮集合
iconSize	icon
currentIndex	默认选中第几个
onTap	选中变换回调函数
fixedColor	选中的颜色
type	BottomNavigationBarType.fixed (当底部导航栏items>3的时候必须设置此属性)

dart

import 'package:flutter/material.dart';
import './data/listData.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("有状态组件"),
        ),
        body: HomePage(),
      ),
    );
  }
}

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

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

class _HomePageState extends State<HomePage> {
  int countNum = 0;
  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        SizedBox(
          height: 200.0,
        ),
        Text("nihao${this.countNum}"),
        SizedBox(
          height: 20.0,
        ),
        RaisedButton(
          onPressed: () {
            setState(() {
              this.countNum++;
            });
            print(this.countNum);
          },
          child: Text("buttom"),
        ),
      ],
    );
  }
}