Flutter实战视频-移动电商-62.购物车_首页Provide化 让跳转随心所欲

62.购物车_首页Provide化 让跳转随心所欲

新建provide/currentIndex.dart

内容比较简单，定义一个变量当前页面的索引currentIndex，再定义一个方法改变它的值

provide全局注册main.dart

index_page.dart

引入provide和currentIndexProvide

然后把首页的代码先都注释掉，之前我们这个页面是一个StateFul的widget，现在我们要改成静态的 原来的一些代码也可以用

下面开始重写index页面

写build内的代码

Scaffold的方法从原来注释的代码里面复制过来，setstate的代码注释掉 用不到 了。我们要用provide

点击事件，调用provide里的改变当前索引值的方法

效果展示

测试页面底部栏目的切换

点击详情页面的购物车按钮，跳转到购物车的页面

pages/details_page/_bottom.dart

购物车的onTap事件

大R刷新，最终效果展示

最终代码

provide/currentIndex.dart

import 'package:flutter/material.dart';

class CurrentIndexProvide with ChangeNotifier{
  int currentIndex=0;

  changeIndex(int newIndex){
    currentIndex=newIndex;
    notifyListeners();//通知
  }
}

pages/index_page.dart

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'home_page.dart';
import 'category_page.dart';
import 'cart_page.dart';
import 'member_page.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:provide/provide.dart';
import '../provide/currentIndex.dart';

class IndexPage extends StatelessWidget {
  
   final List<BottomNavigationBarItem> bottomTabs=[
      BottomNavigationBarItem(
      icon:Icon(CupertinoIcons.home),//这里使用IOS风格的
      title: Text('首页')
    ),
    BottomNavigationBarItem(
      icon:Icon(CupertinoIcons.search),
      title: Text('分类')
    ),
    BottomNavigationBarItem(
      icon:Icon(CupertinoIcons.shopping_cart),
      title: Text('购物车')
    ),
    BottomNavigationBarItem(
      icon:Icon(CupertinoIcons.profile_circled),
      title: Text('会员中心')
    ) 
  ];
  final List<Widget> tabBodies=[
    HomePage(),
    CategoryPage(),
    CartPage(),
    MemberPage()
  ];

  @override
  Widget build(BuildContext context) {
    ScreenUtil.instance = ScreenUtil( 750,height: 1334)..init(context);
    return Provide<CurrentIndexProvide>(
      builder: (context,child,val){
        int currentIndex=Provide.value<CurrentIndexProvide>(context).currentIndex;
        return Scaffold(
          backgroundColor: Color.fromRGBO(244, 245, 245, 1.0),//颜色固定死，比白色稍微灰一点
          bottomNavigationBar: BottomNavigationBar(
            type:BottomNavigationBarType.fixed,
            currentIndex: currentIndex,//当前索引值
            items: bottomTabs,
            onTap: (index){
              Provide.value<CurrentIndexProvide>(context).changeIndex(index);
            },
          ),
          body: IndexedStack(
            index: currentIndex,
            children: tabBodies,
          ),
        );
      },
    );
  }
}

pages/details_page/details_bottom.dart

import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:provide/provide.dart';
import '../../provide/cart.dart';
import '../../provide/details_info.dart';
import '../../provide/currentIndex.dart';

class DetailsBottom extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var goodsInfo=Provide.value<DetailsInfoProvide>(context).goodsInfo.data.goodInfo;//当前商品的详情
    var goodsId=goodsInfo.goodsId;
    var goodsName=goodsInfo.goodsName;
    var count=1;//默认为1
    var price=goodsInfo.presentPrice;
    var images=goodsInfo.image1;


    return Container(
       ScreenUtil().setWidth(750),
      color: Colors.white,
      height: ScreenUtil().setHeight(80),
      child: Row(
        children: <Widget>[
          InkWell(
            onTap: (){
              Provide.value<CurrentIndexProvide>(context).changeIndex(2);
              Navigator.pop(context);
            },
            child: Container(
               ScreenUtil().setWidth(110),
              alignment: Alignment.center,
              child: Icon(
                Icons.shopping_cart,
                size:35,//图标没有自适应 要是设置size的大小
                color: Colors.red,
              ),
            ),            
          ),
          InkWell(
            onTap: () async{
              await Provide.value<CartProvide>(context).save(goodsId, goodsName, count, price, images);
            },
            child: Container(
              alignment: Alignment.center,
               ScreenUtil().setWidth(320),//750 - 110 再除以2 评分
              height: ScreenUtil().setHeight(80),
              color: Colors.green,
              child: Text(
                '加入购物车',
                style:TextStyle(color:Colors.white,fontSize: ScreenUtil().setSp(28)),
              ),
            ),
          ),
          InkWell(
            onTap: () async{
              await Provide.value<CartProvide>(context).remove();
            },
            child: Container(
              alignment: Alignment.center,
               ScreenUtil().setWidth(320),//750 - 110 再除以2 评分
              height: ScreenUtil().setHeight(80),
              color: Colors.red,
              child: Text(
                '立即购买',
                style:TextStyle(color:Colors.white,fontSize: ScreenUtil().setSp(28)),
              ),
            ),
          )
        ],
      ),
    );
  }
}