import 'package:flutter/material.dart';

import 'each_view.dart';

class BottomAppBarDemo extends StatefulWidget {

  _BottomAppBarDemoState createState() => _BottomAppBarDemoState();

}

class _BottomAppBarDemoState extends State<BottomAppBarDemo> {

  List<Widget> _eachView; //创建视图数组

  int _index = 0; //数组索引，通过改变索引值改变视图

  @override

  void initState() {

    // TODO: implement initState

    super.initState();

    _eachView = List();

    _eachView

      ..add(EachView('Home'))

      ..add(EachView('Home1'))

      ..add(EachView('Home2'))

      ..add(EachView('Home3'))

      ..add(EachView('Home4'));

  }

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      body: _eachView[_index],

      floatingActionButton: FloatingActionButton(

        onPressed: () {

          Navigator.of(context)

              .push(MaterialPageRoute(builder: (BuildContext context) {

            return EachView('New Page');

          }));

        },

        tooltip: 'Increment',

        child: Icon(

          Icons.add,

          color: Colors.white,

        ),

        backgroundColor: Colors.green,

      ),

      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,

      bottomNavigationBar: BottomAppBar(

        color: Colors.white,

        shape: CircularNotchedRectangle(),

        child: Row(

          mainAxisSize: MainAxisSize.max,

          mainAxisAlignment: MainAxisAlignment.spaceAround,

          children: <Widget>[

            IconButton(

                icon: Icon(Icons.accessible_forward),

//                color: Colors.white,

                onPressed: () {

                  setState(() {

                    _index = 0;

                  });

                }),

                IconButton(

                    icon: Icon(Icons.access_alarm),

//                color:Colors.white,

                    onPressed: () {

                      setState(() {

                        _index = 1;

                      });

                    }),

            IconButton(

                icon: Icon(Icons.accessible_forward),

                color: Colors.transparent,

                onPressed: () {

                  setState(() {

                    _index = 2;

                  });

                }),

            IconButton(

                icon: Icon(Icons.account_balance_wallet),

//                color:Colors.white,

                onPressed: () {

                  setState(() {

                    _index = 3;

                  });

                }),

            IconButton(

                icon: Icon(Icons.airport_shuttle),

//                color:Colors.white,

                onPressed: () {

                  setState(() {

                    _index = 4;

                  });

                }),

          ],

        ),

      ),

    );

  }

}

import 'package:flutter/material.dart';

class EachView extends StatefulWidget {

  String _title;

  EachView(this._title);

  @override

  _EachViewState createState() => _EachViewState();

}

class _EachViewState extends State<EachView> {

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar:AppBar(title:Text(widget._title)),

      body: Center(child:Text(widget._title)),

    );

  }

}