flutter实现左侧导航，拿走即用

import 'package:flutter/material.dart';

// import 'package:flutter_bjoil/http/dao/classify/categoryList_dao.dart';

// import 'package:flutter_bjoil/model/classify/categoryList_mo.dart';

// import 'package:flutter_bjoil/util/toast.dart';

// import 'package:flutter_bjoil/util/view_util.dart';

// import 'package:flutter_bjoil/widget/navigation_bar.dart';

// import 'package:flutter_bjoil/widget/search_bar.dart';

// import 'package:hi_net/core/hi_error.dart';

class CartPage extends StatefulWidget {

  const CartPage({Key? key}) : super(key: key);

  @override

  _CartPageState createState() => _CartPageState();

}

class _CartPageState extends State {

  // List categoryList = [];

  int currentIndex = 0; // 左侧导航下标