核心代码

bottomNavigationBar: BottomNavigationBar(items: const [
  BottomNavigationBarItem(icon: Icon(Icons.home), label: "首页"),
  BottomNavigationBarItem(icon: Icon(Icons.category), label: "分类"),
])

完整代码

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'jdshop',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: '京东商城'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: const Text("我是首页"),
      bottomNavigationBar: BottomNavigationBar(items: const [
        BottomNavigationBarItem(icon: Icon(Icons.home), label: "首页"),
        BottomNavigationBarItem(icon: Icon(Icons.category), label: "分类"),
      ]),
    );
  }
}