react + redux 之美团案例-编程知识

1.案例展示

![](https://img-blog.csdnimg.cn/direct/b7a9604e5d274504ad630427a996aa8b.png
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2.环境搭建

克隆项目到本地（内置了基础静态组件和模版）

git clone http://git.itcast.cn/heimaqianduan/redux-meituan.git

安装所有依赖

npm i

启动mock服务（内置了json-server）

npm run serve

启动前端服务

npm run start

3.分类和商品列表渲染

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1.store modules 下 takeaway.js文件

// 编写store
import { createSlice } from "@reduxjs/toolkit"
import axios from "axios"const foodsStore = createSlice({name: 'foods',initialState: {// 商品列表foodsList: [],a},reducers: {// 更改商品列表setFoodsList (state, action) {state.foodsList = action.payload}}
})// 异步获取部分
const { setFoodsList} = foodsStore.actions
const fetchFoodsList = () => {return async (dispatch) => {// 编写异步逻辑const res = await axios.get('http://localhost:3004/takeaway')// 调用dispatch函数提交actiondispatch(setFoodsList(res.data))}
}export { fetchFoodsList }const reducer = foodsStore.reducer
export default reducer

2.store下index.js文件

import foodsReducer from './modules/takeaway'
import { configureStore } from '@reduxjs/toolkit'
const store = configureStore({reducer: {foods: foodsReducer}
})
export default store

3.app.js

import { useDispatch, useSelector } from 'react-redux'
import { fetchFoodsList } from './store/modules/takeaway'
import { useEffect } from 'react'
// 触发action执行// 1. useDispatch -> dispatch 2. actionCreater导入进来 3.useEffectconst dispatch = useDispatch()useEffect(() => {dispatch(fetchFoodsList())}, [dispatch])// 获取foodsList渲染数据列表// 1. useSelectorconst { foodsList } = useSelector(state => state.foods){/* 外卖商品列表 */}{foodsList.map((item, index) => {return (<FoodsCategorykey={item.tag}// 列表标题name={item.name}// 列表商品foods={item.foods}/>)})}

4.menu.js

import { useDispatch,useSelector } from 'react-redux'
const dispatch = useDispatch()
const {foodsList} = useSelector(state=>state.foods)

5.index.js

// 注入store
import { Provider } from 'react-redux'
import store from './store'
const root = createRoot(document.getElementById('root'))
root.render(<Provider store={store}><App /></Provider>
)

4.点击分类激活实现

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1.store modules下 takeaway.js文件


// 编写store
import { createSlice } from "@reduxjs/toolkit"
import axios from "axios"
const foodsStore = createSlice({name: 'foods',initialState: {// 商品列表foodsList: [],//激活indexactiveIndex:0,},reducers: {// 更改商品列表setFoodsList (state, action) {state.foodsList = action.payload},//更改activeIndexchangeActiveIndex(state,action){state.activeIndex = action.payload}}
})// 异步获取部分
const { setFoodsList,changeActiveIndex} = foodsStore.actions

2.menu.js

import classNames from 'classnames'
import './index.scss'import { useDispatch,useSelector } from 'react-redux'
import { changeActiveIndex} from '../../store/modules/takeaway'
const Menu = () => {const dispatch = useDispatch()const {foodsList,activeIndex} = useSelector(state=>state.foods) const menus = foodsList.map(item => ({ tag: item.tag, name: item.name }))return (<nav className="list-menu">{/* 添加active类名会变成激活状态 */}{menus.map((item, index) => {return (<divonClick={() => dispatch(changeActiveIndex(index))}key={item.tag}className={classNames('list-menu-item',activeIndex === index && 'active')}>{item.name}</div>)})}</nav>)
}export default Menu

3.app.js

const { foodsList , activeIndex} = useSelector(state => state.foods)
<div className="goods-list">{/* 外卖商品列表 */}{foodsList.map((item, index) => {return (activeIndex==index && <FoodsCategorykey={item.tag}// 列表标题name={item.name}// 列表商品foods={item.foods}/>)})}</div>

5.添加购物车

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1.takeaway.js

// 编写storeimport { createSlice } from "@reduxjs/toolkit"
import axios from "axios"const foodsStore = createSlice({name: 'foods',initialState: {// 商品列表foodsList: [],// 菜单激活下标值activeIndex: 0,// 购物车列表cartList: []},reducers: {// 更改商品列表setFoodsList (state, action) {state.foodsList = action.payload},// 更改activeIndexchangeActiveIndex (state, action) {state.activeIndex = action.payload},// 添加购物车addCart (state, action) {// 是否添加过？以action.payload.id去cartList中匹配 匹配到了 添加过const item = state.cartList.find(item => item.id === action.payload.id)if (item) {item.count++} else {state.cartList.push(action.payload)}},}
})const { setFoodsList, changeActiveIndex, addCart} = foodsStore.actions
export { fetchFoodsList, changeActiveIndex, addCart}

2.foodItem下index.js文件

import { useDispatch } from 'react-redux'
import { setCarlist } from '../../../store/modules/takeaway'
const dispatch = useDispatch()<div className="goods-count"><span className="plus" onClick={() => dispatch(setCarlist({id,picture,name,unit,description,food_tag_list,month_saled,like_ratio_desc,price,tag,count}))}></span></div>

6.统计区域功能实现

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1.cart下面index.js

import classNames from 'classnames'
import { useState } from 'react'
import { useDispatch, useSelector } from 'react-redux'
import Count from '../Count'
import './index.scss'const Cart = () => {const { carList } = useSelector(state => state.foods)// 计算总价 const totalPrice = carList.reduce((a, c) => a + c.price * c.count, 0)return (<div className="cartContainer"><div className="cart">{/* fill 添加fill类名购物车高亮*/}{/* 购物车数量 */}<div  className={classNames('icon', carList.length > 0 && 'fill')}>{carList.length > 0 && <div className="cartCornerMark">{carList.length}</div>}</div>{/* 购物车价格 */}<div className="main"><div className="price"><span className="payableAmount"><span className="payableAmountUnit">¥</span>{totalPrice.toFixed(2)}</span></div><span className="text">预估另需配送费 ¥5</span></div>{/* 结算 or 起送 */}{carList.length > 0 ? (<div className="goToPreview">去结算</div>) : (<div className="minFee">1元起送</div>)}</div>{/* 添加visible类名 div会显示出来 */}<div className={classNames('cartPanel')}><div className="header"><span className="text">购物车</span><span className="clearCart">清空购物车</span></div>{/* 购物车列表 */}<div className="scrollArea">{carList.map(item => {return (<div className="cartItem" key={item.id}><img className="shopPic" src={item.picture} alt="" /><div className="main"><div className="skuInfo"><div className="name">{item.name}</div></div><div className="payableAmount"><span className="yuan">¥</span><span className="price">{item.price}</span></div></div><div className="skuBtnWrapper btnGroup">{/* 数量组件 */}<Countcount={item.count}/></div></div>)})}</div></div></div>)
}export default Cart

7.购物车列表功能实现

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1.takeaway.js

// 编写storeimport { createSlice } from "@reduxjs/toolkit"
import axios from "axios"const foodsStore = createSlice({name: 'foods',initialState: {// 商品列表foodsList: [],//激活indexactiveIndex:0,//汽车carList:[]},reducers: {// 更改商品列表setFoodsList (state, action) {state.foodsList = action.payload},//更改activeIndexchangeActiveIndex(state,action){state.activeIndex = action.payload},setCarlist(state,action){// 是否添加过？以action.payload.id去cartList中匹配 匹配到了 添加过const item = state.carList.find(item => item.id === action.payload.id)if (item) {item.count++} else {state.carList.push(action.payload)}},increCount(state,action){const item = state.carList.find(item => item.id === action.payload.id)item.count++},decreCount(state,action){const item = state.carList.find(item => item.id === action.payload.id)if(item.count===0){return}item.count--},// 清除购物车clearCart (state) {state.carList = []}}
})// 异步获取部分
const { setFoodsList,changeActiveIndex,setCarlist,increCount,decreCount,clearCart} = foodsStore.actions
const fetchFoodsList = () => {return async (dispatch) => {// 编写异步逻辑const res = await axios.get('http://localhost:3004/takeaway')// 调用dispatch函数提交actiondispatch(setFoodsList(res.data))}
}export { fetchFoodsList ,changeActiveIndex,setCarlist,increCount,decreCount,clearCart}const reducer = foodsStore.reducerexport default reducer

2.cart下index文件

import classNames from 'classnames'
import { useDispatch, useSelector } from 'react-redux'
import Count from '../Count'
import './index.scss'
import {increCount,decreCount,clearCart} from '../../store/modules/takeaway'const Cart = () => {const { carList } = useSelector(state => state.foods)// 计算总价 const totalPrice = carList.reduce((a, c) => a + c.price * c.count, 0)const dispatch = useDispatch()return (<div className="cartContainer"><div className="cart">{/* fill 添加fill类名购物车高亮*/}{/* 购物车数量 */}<div  className={classNames('icon', carList.length > 0 && 'fill')}>{carList.length > 0 && <div className="cartCornerMark">{carList.length}</div>}</div>{/* 购物车价格 */}<div className="main"><div className="price"><span className="payableAmount"><span className="payableAmountUnit">¥</span>{totalPrice.toFixed(2)}</span></div><span className="text">预估另需配送费 ¥5</span></div>{/* 结算 or 起送 */}{carList.length > 0 ? (<div className="goToPreview">去结算</div>) : (<div className="minFee">1元起送</div>)}</div>{/* 添加visible类名 div会显示出来 */}<div className={classNames('cartPanel',carList.length>0&&'visible')} ><div className="header"><span className="text">购物车</span><span className="clearCart" onClick={()=>dispatch(clearCart())}>清空购物车</span></div>{/* 购物车列表 */}<div className="scrollArea">{carList.map(item => {return (<div className="cartItem" key={item.id}><img className="shopPic" src={item.picture} alt="" /><div className="main"><div className="skuInfo"><div className="name">{item.name}</div></div><div className="payableAmount"><span className="yuan">¥</span><span className="price">{item.price}</span></div></div><div className="skuBtnWrapper btnGroup">{/* 数量组件 */}<Countcount={item.count}onPlus={()=>dispatch(increCount({id:item.id}))}onMinus={()=>dispatch(decreCount({id:item.id}))}/></div></div>)})}</div></div></div>)
}export default Cart

8.控制购物车显示和隐藏

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1.cart文件下index.js文件

import classNames from 'classnames'
import { useDispatch, useSelector} from 'react-redux'
import { useState } from 'react'
import Count from '../Count'
import './index.scss'
import {increCount,decreCount,clearCart} from '../../store/modules/takeaway'const Cart = () => {const { carList } = useSelector(state => state.foods)// 计算总价 const totalPrice = carList.reduce((a, c) => a + c.price * c.count, 0)const [visible,setVisible]= useState(false)const dispatch = useDispatch()const onShow = () => {if (carList.length > 0) {setVisible(true)}}return (<div className="cartContainer">{/* 遮罩层 添加visible类名可以显示出来 */}<divclassName={classNames('cartOverlay', visible && 'visible')}onClick={() => setVisible(false)}/><div className="cart">{/* fill 添加fill类名购物车高亮*/}{/* 购物车数量 */}<div onClick={onShow}  className={classNames('icon', carList.length > 0 && 'fill')}>{carList.length > 0 && <div className="cartCornerMark">{carList.length}</div>}</div>{/* 购物车价格 */}<div className="main"><div className="price"><span className="payableAmount"><span className="payableAmountUnit">¥</span>{totalPrice.toFixed(2)}</span></div><span className="text">预估另需配送费 ¥5</span></div>{/* 结算 or 起送 */}{carList.length > 0 ? (<div className="goToPreview">去结算</div>) : (<div className="minFee">1元起送</div>)}</div>{/* 添加visible类名 div会显示出来 */}<div className={classNames('cartPanel',visible &&'visible')} ><div className="header"><span className="text">购物车</span><span className="clearCart" onClick={()=>dispatch(clearCart())}>清空购物车</span></div>{/* 购物车列表 */}<div className="scrollArea">{carList.map(item => {return (<div className="cartItem" key={item.id}><img className="shopPic" src={item.picture} alt="" /><div className="main"><div className="skuInfo"><div className="name">{item.name}</div></div><div className="payableAmount"><span className="yuan">¥</span><span className="price">{item.price}</span></div></div><div className="skuBtnWrapper btnGroup">{/* 数量组件 */}<Countcount={item.count}onPlus={()=>dispatch(increCount({id:item.id}))}onMinus={()=>dispatch(decreCount({id:item.id}))}/></div></div>)})}</div></div></div>)
}export default Cart