farmer_client/lib/pages/TabBar/index_page.dart

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'home_page.dart';
import 'Information_page.dart';
import 'Mine_page.dart';
import 'Orders_page.dart';

class IndexPage extends StatefulWidget {
  _IndexPageState createState() => _IndexPageState();
}

class _IndexPageState extends State<IndexPage> {


  final List<BottomNavigationBarItem> bottomTabs = [
     BottomNavigationBarItem(
      icon: Icon(CupertinoIcons.home),
      title: Text('首页'),
    ),
     BottomNavigationBarItem(
      icon: Icon(CupertinoIcons.search),
      title: Text('资讯'),

    ),
     BottomNavigationBarItem(
      icon: Icon(CupertinoIcons.shopping_cart),
      title: Text('订单'),

    ),
     BottomNavigationBarItem(
      icon: Icon(CupertinoIcons.profile_circled),
      title: Text('我的'),
    ),
  ];

  final List tabBodies = [
    HomePage(),
    InformationPage(),
    OrdersPage(),
    MinePage(),
  ];

  int currentIndex = 0;
  var currentPage;

  @override
  void initState() {
    super.initState();
    currentPage = tabBodies[currentIndex];
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      backgroundColor: Color.fromRGBO(244, 245, 245, 1),
      bottomNavigationBar: BottomNavigationBar(
        type: BottomNavigationBarType.fixed,
        currentIndex: currentIndex,
        items: bottomTabs,
        onTap: (index){
          setState(() {
            currentIndex = index;
            currentPage = tabBodies[currentIndex];
          });
        },
      ),
      body: currentPage,
    );
  }
}