Flutter移动电商实战 --（26）列表页_使用Provide控制子类-2

主要实现功能，点击一级分类，二级分类跟着变。这里主要用我们的provide

新建provide

provide文件夹下创建：child_category.dart

事件上就是这个实体：BxMallSubDto

这样我们的Provide类就写完了。

然后在main.dart中注册provide

import './provide/child_category.dart';

继续category_page.dart

先引入我们的provide和childCategory的provide

import 'package:provide/provide.dart';
import '../provide/child_category.dart';

给左侧的类别加事件

左侧每个元素的点击事件

右侧的小分类

移动过来以后呢，这里就报错了，因为我们的list已经注释带掉了不用了。

效果展示

点击左侧大类会显示右侧的小类别

增加点击的左侧大类，高亮效果

我们用setState去解决这个问题

最终展示效果

最终代码

provide/child_category.dart

import 'package:flutter/material.dart';
import '../model/category.dart';

class ChildCategory with ChangeNotifier{
 List<BxMallSubDto> childCategoryList=[];
  
  getChildCategory(List list)
  {
    childCategoryList=list;
    notifyListeners();//监听
  }
}

lib/main.dart

import 'package:flutter/material.dart';
import './pages/index_page.dart';
import 'package:provide/provide.dart';
import './provide/counter.dart';
import './provide/child_category.dart';


void main(){
 var counter=Counter();
 var providers=Providers();
 var childCategory=ChildCategory();
 //注册 依赖
 providers
 ..provide(Provider<Counter>.value(counter))
 ..provide(Provider<ChildCategory>.value(childCategory)); 
  runApp(ProviderNode(child: MyApp(),providers: providers,));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child:MaterialApp(
        title:'百姓生活+',
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          primaryColor: Colors.pink
        ),
        home: IndexPage(),
      )
    );
  }
}

category_page.dart

import 'package:flutter/material.dart';
import '../service/service_method.dart';
import 'dart:convert';
import '../model/category.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:provide/provide.dart';
import '../provide/child_category.dart';

class CategoryPage extends StatefulWidget {
  @override
  _CategoryPageState createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {
  @override
  Widget build(BuildContext context) {
    //_getCategory();
    return Scaffold(
      appBar: AppBar(title: Text('商品分类'),),
      body: Container(
        child: Row(
          children: <Widget>[
            LeftCategoryNav(),
            Column(
              children: <Widget>[
                RightCategoryNav()
              ],
            )
          ],
        ),
      ),
    );
  }

 
}

//左侧大类导航
class LeftCategoryNav extends StatefulWidget {
  @override
  _LeftCategoryNavState createState() => _LeftCategoryNavState();
}

class _LeftCategoryNavState extends State<LeftCategoryNav> {
  List list=[];
  var listIndex=0;
  @override
  void initState() { 
    super.initState();
    _getCategory();//请求接口的数据
  }
  @override
  Widget build(BuildContext context) {
    return Container(
      width: ScreenUtil().setWidth(180),
      decoration: BoxDecoration(
        border: Border(
          right: BorderSide(width:1.0,color: Colors.black12),//有边框
        )
      ),
      child: ListView.builder(
        itemCount: list.length,
        itemBuilder: (contex,index){
          return _leftInkWell(index);
        },
      ),
    );
  }

  Widget _leftInkWell(int index){
    bool isClick=false;
    isClick=(index==listIndex)?true:false;
    return InkWell(
      onTap: (){
        setState(() {
         listIndex=index; 
        });
        var childList=list[index].bxMallSubDto;//当前大类的子类的列表
        Provide.value<ChildCategory>(context).getChildCategory(childList);
      },
      child: Container(
        height: ScreenUtil().setHeight(100),
        padding: EdgeInsets.only(left:10.0,top:10.0),
        decoration: BoxDecoration(
          color: isClick?Colors.black26: Colors.white,
          border: Border(
            bottom: BorderSide(width: 1.0,color: Colors.black12)
          )
        ),
        child: Text(
          list[index].mallCategoryName,
          style: TextStyle(fontSize: ScreenUtil().setSp(28)),//设置字体大小，为了兼容使用setSp
        ),
      ),
    );
  }
   void _getCategory() async{
    await request('getCategory').then((val){
      var data=json.decode(val.toString());
      //print(data);
      CategoryModel category= CategoryModel.fromJson(data);
      setState(() {
       list=category.data; 
      });
      //list.data.forEach((item)=>print(item.mallCategoryName));
    });
  }
}

class RightCategoryNav extends StatefulWidget {
  @override
  _RightCategoryNavState createState() => _RightCategoryNavState();
}

class _RightCategoryNavState extends State<RightCategoryNav> {
  //List list = ['名酒','宝丰','北京二锅头','舍得','五粮液','茅台','散白'];
  @override
  Widget build(BuildContext context) {
    return Provide<ChildCategory>(
      builder: (context,child,childCategory){
        return  Container(
          height: ScreenUtil().setHeight(80),
          width: ScreenUtil().setWidth(570),//总的宽度是750 -180
          decoration: BoxDecoration(
            color: Colors.white,//白色背景
            border: Border(
              bottom: BorderSide(width: 1.0,color: Colors.black12)//边界线
            )
          ),
          child: ListView.builder(
            scrollDirection: Axis.horizontal,
            itemCount: childCategory.childCategoryList.length,
            itemBuilder: (context,index){
              return _rightInkWell(childCategory.childCategoryList[index]);
            },
          ),
        );
      }
    );
  }

  Widget _rightInkWell(BxMallSubDto item){
    return InkWell(
      onTap: (){},//事件留空
      child: Container(//什么都加一个container，这样好布局
        padding: EdgeInsets.fromLTRB(5.0, 10.0, 5.0, 10.0),//上下是10 左右是5.0
        child: Text(
          item.mallSubName,
          style:TextStyle(fontSize: ScreenUtil().setSp(28)),
        ),
      ),
    );
  }
}

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