长沙制作网站的公司/南宁网站建设公司排行

一.redux使用

1.安装

npm i  redux

例一：

2.创建redux文件夹，store.js文件

store.js文件

import {legacy_createStore as createStore,combineReducers}from "redux"
// 每一块状态内容对应一个reducer文件
import {CollApsedReducer} from "./CollapsedReducer"
import {LoadingReducer}from "./LoadingReducer"
// combineReducers合并多个reducer
const reducer=combineReducers({CollApsedReducer,LoadingReducer
})
// createStore里面只能放一个reducer,所以上面合并处理一下
const store=createStore(reducer)
export default store

3.将提供者绑定到跟组件内外层，使每个被包裹的组件都可以使用store

import React from 'react';
import IndexRouter from "../src/router"
import {Provider}from "react-redux"
import store from "../src/redux/store"
function App() {return (<Provider store={store}><IndexRouter /></Provider>);
}
export default App;

4.更改状态

import React , { useState }from 'react'
import { Layout,Button ,Avatar, Space,Dropdown } from 'antd';
import {MenuFoldOutlined,MenuUnfoldOutlined,UserOutlined} from '@ant-design/icons';import { useHistory } from 'react-router-dom'import {connect}from "react-redux"
const { Header } = Layout;
// 接收props并使用function TopHeader(props) {console.log(props);// const [collapsed, setCollapsed] = useState(false);const history = useHistory()const isCollapsed=()=>{props.changeCollapsed()}const items = [{key: '1',primary: true,label: '超级管理员',},{key: '2',danger: true,label: '退出登录',},];const onClick = ({ key }) => {  if(key==="2"){localStorage.removeItem("token")history.push({pathname: '/login'})}};return (<Header style={{ padding: 0, }}><Buttontype="text"// 使用仓库的折叠状态icon={props.isCollapsed ? <MenuUnfoldOutlined  /> : <MenuFoldOutlined />}// 更改actiononClick={()=>isCollapsed()}style={{fontSize: '16px',width: 64,height: 64,}}/><div style={{float:'right',marginRight:"20px"}}><span style={{marginRight:"20px"}}>欢迎admin回来</span><Dropdown menu={{ items,onClick}}><a onClick={(e) => e.preventDefault()}><Space><Avatar size="large" icon={<UserOutlined />}  /></Space></a></Dropdown></div></Header>)
}
// 更新props
const mapStateToProps=({CollApsedReducer:{isCollapsed}})=>{return{isCollapsed}
}
// 更新action
const mapDispatchToProps={changeCollapsed(){return {type:"change_collapsed"}}
}
// connect()(组件名)
// connect函数将组件连接到store仓库
export default connect(mapStateToProps,mapDispatchToProps)(TopHeader)

5.使用状态变化的组件

import React, { useState, useEffect } from 'react';
import { useHistory, withRouter } from 'react-router-dom';
import { Layout, Menu } from 'antd';
import { UserOutlined, DesktopOutlined, FileOutlined, PieChartOutlined, TeamOutlined } from '@ant-design/icons';
import "../newssandbox/index.css";
// 引入connect
import {connect}from "react-redux"
const { Sider } = Layout;
const { SubMenu } = Menu;function SideMenu(props) {// props接收const [selectedKey, setSelectedKey] = useState(null);const select=[props.location.pathname.split("/")[1]]const history = useHistory();const onClick = (e) => {history.push(e.key);};useEffect(() => {// 根据路由变化更新选中的菜单项const currentPath = props.location.pathname;setSelectedKey(currentPath);}, [props.location.pathname]);function renderMenuItems(items) {return items.map((item) => {if (item.children) {return (<SubMenu key={item.key} icon={item.icon} title={item.label}>{renderMenuItems(item.children)}</SubMenu>);} else {return (<Menu.Item key={item.key} icon={item.icon}>{item.label}</Menu.Item>);}});}const items = [{key: '/home',label: '首页',icon: <PieChartOutlined />,},{key: 'user-manage',label: '用户管理',icon: <DesktopOutlined />,children: [{ key: '/user-manage/list', label: '用户列表', icon: <DesktopOutlined /> }],},{key: 'right-manage',label: '权限管理',icon: <UserOutlined />,children: [{ key: '/right-manage/role/list', label: '角色列表' },{ key: '/right-manage/right/list', label: '权限列表' }],},{key: 'news-manage',label: '新闻管理',icon: <TeamOutlined />,children: [{ key: '/news-manage/add', label: "撰写新闻" },{ key: '/news-manage/draft', label: '草稿箱' },{ key: '/news-manage/category', label: '新闻分类' }],},{key: 'audit-manage',label: '审核管理',icon: <FileOutlined />,children: [{ key: '/audit-manage/audit', label: "审核新闻" },{ key: '/audit-manage/list', label: '审核列表' },],},{key: 'publish-manage',label: '发布管理',icon: <FileOutlined />,children: [{ key: '/publish-manage/unpublished', label: "待发布" },{ key: '/publish-manage/published', label: '已发布' },{ key: '/publish-manage/sunset', label: '已下线' }],},];return (<div>{/* props.isCollapsed使用 */}<Sider trigger={null} collapsible collapsed={props.isCollapsed}><div className="demo-logo-vertical">全球新闻发布管理系统</div><Menutheme="dark"mode="inline"defaultSelectedKeys={['home']}selectedKeys={[selectedKey]}defaultOpenKeys={select}onClick={onClick}>{renderMenuItems(items)}</Menu></Sider></div>);
}
// {CollApsedReducer:{isCollapsed}}CollApsedReducer reducer文件导出的变量名,isCollapsed状态，此处进行解构
const mapStateToProps=({CollApsedReducer:{isCollapsed}})=>{return{isCollapsed}
}
export default connect(mapStateToProps)(withRouter(SideMenu));

例二：

1.新建LoadingReducer.js文件

export const LoadingReducer=(prevState={loading:false
},action)=>{let {type,payload}=actionswitch (type) {case 'change_loading':// 复制老状态,不可直接修改let newState={...prevState}newState.loading=payloadreturn newState default:return prevState}
}

2.路由文件

import React from 'react'
import {Route,Switch,Redirect}from "react-router-dom"
import Home from "../../views/newssandbox/home/Home"
import UserList from "../../views/newssandbox/user-mange/UserList"    
import RoleList from"../../views/newssandbox/right-manage/RoleList" 
import RightList from"../../views/newssandbox/right-manage/RightList" 
import NoPermission from "../../views/newssandbox/nopermission/Nopermission" 
import NewsAdd from "../../views/newssandbox/news-manage/NewsAdd"
import NewsDraft from "../../views/newssandbox/news-manage/NewsDraft"
import NewsCategory from "../../views/newssandbox/news-manage/NewsCategory"import AuditManage from "../../views/newssandbox/audit-manage/AuditManage"
import AuditList from "../../views/newssandbox/audit-manage/AuditList"import Unpublished from "../../views/newssandbox/publish-manage/Unpublished"import Publishedd from "../../views/newssandbox/publish-manage/Publishedd"
import Sunset from "../../views/newssandbox/publish-manage/Sunset"
import {  Spin } from 'antd';import {connect}from "react-redux"function NewsRouter(props) {return (<div>{/* 为每个页面使用loading功能 */}<Spin size="large" style={{marginTop:"200px"}} spinning={props.loading} ><Switch><Route path="/home" component={Home}/><Route path="/user-manage/list" component={UserList}/><Route path="/right-manage/role/list" component={RoleList}/><Route path="/right-manage/right/list" component={RightList}/><Route path="/news-manage/add" component={NewsAdd}/><Route path="/news-manage/draft" component={NewsDraft}/><Route path="/news-manage/category" component={NewsCategory}/><Route path="/audit-manage/audit" component={AuditManage}/><Route path="/audit-manage/list" component={AuditList}/><Route path="/publish-manage/unpublished" component={Unpublished}/><Route path="/publish-manage/published" component={Publishedd}/><Route path="/publish-manage/sunset" component={Sunset}/>{/* 如果访问根路径回车精确匹配重定向到home页面 */}<Redirect from="/" to="/home" exact/>{/* 如果是随便输入或除了以上路径的其他路径显示404页面 */}<Route path="*" component={NoPermission}/></Switch> </Spin></div>)
}const mapStateToProps=({LoadingReducer:{loading}})=>{return{loading}}const mapDispatchToProps={changeCollapsed(){return {type:"change_loading"}}}
export default connect(mapStateToProps,mapDispatchToProps)(NewsRouter)

3.在axios封装文件内使用

import axios from "axios";
import store from "../redux/store";
axios.defaults.baseURL = "http://localhost:3000";axios.interceptors.request.use((config) => {//  显示loadingstore.dispatch({type: "change_loading",payload: true,});return config;},(error) => {return Promise.reject(error);}
);axios.interceptors.response.use((response) => {//  隐藏loadingstore.dispatch({type: "change_loading",payload: false,});return response;},(error) => {//  隐藏loadingstore.dispatch({type: "change_loading",payload: false,});return Promise.reject(error);}
);export default axios;

二.持久化

1.安装

npm i redux-persist

2.store.js文件配置持久化

import {legacy_createStore as createStore,combineReducers}from "redux"import {CollApsedReducer} from "./CollapsedReducer"
import {LoadingReducer}from "./LoadingReducer"//配置数据的持久化效果
import { persistReducer, persistStore } from "redux-persist";
//导入需要配置的数据源，可以选择，storage，cookie,session等
import storage from "redux-persist/lib/storage";const reducer=combineReducers({CollApsedReducer,LoadingReducer
})
//定义配置的信息
const persitConfig = {// 代表存储名,随便起key:"root",storage,// 如果不想将部分state持久化，也可以将其放入黑名单(blacklist)中,白名单whitelist
//    将loading 模块不做持久化blacklist:["LoadingReducer"]
}
//创建持久化的配置persist的信息
const persistReducers = persistReducer(persitConfig,reducer);
//创建存储对象并且抛出对象
const store=createStore(persistReducers)const persistor =persistStore(store);export{store,persistor}

3.仓库导出方式更改了，组件引入方式要改变

4.根组件内使用PersistGate

import React from 'react';
import IndexRouter from "../src/router"
import {Provider}from "react-redux"
import {store,persistor} from "../src/redux/store"
// 在入口文件中使用 PersistGate 包裹根组件。将延迟渲染app 视图直到持久化状态取回并保存到redux中
import {PersistGate}from "redux-persist/integration/react"
function App() {return (<Provider store={store}><PersistGate loading={null} persistor={persistor}><IndexRouter /></PersistGate></Provider>);
}
export default App;