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redux的使用(二)--redux-actions

redux的使用(二)--redux-actions

作者: 龙猫六六 | 来源:发表于2020-11-17 13:34 被阅读0次

    安装

    源码:https://github.com/redux-utilities/redux-actions
    安装:yarn add redux-actionsnpm install --save redux-actions

    使用方式

    通过一个案例记录下redux-actions的使用。

    • 步骤一.reducx-actions是在redux的基础上,对actions和reducer进行优化和管理。因为需要定义store
    • 步骤二.新建actionType.js:定义action的类型
    • 步骤三.新建action.js:调用createActioncreateActions去定义action
    • 步骤四.新建reducer.js:调用handleActionhandleActions去监听action
    • 步骤五.App.js使用react-reduxconnetProvider去维护管理store,并正确使用store的值和方法赋值给控件的this.props

    以下通过代码按步骤进行编码

    步骤一 定义store

    //store/index.js
    import {createStore, applyMiddleware,compose} from 'redux'
    import reducer from "./reducer";
    const store = createStore(reducer)
    export default store
    

    创建index.js:调用redux的api函数createStore新建store,reducer用来监听action及处理对应action的函数

    步骤二 定义action.type

    新建actioType.js定义行为类型,为了保证行为类型宏定义,不易写错。
    定义了两个行为GET_STUDENT_LISTADD_STUDENT_LIST

    //actioType.js
    const GET_STUDENT_LIST = 'get_student_list'
    const ADD_STUDENT_LIST = 'add_student_list'
    export default {GET_STUDENT_LIST, ADD_STUDENT_LIST}
    

    步骤三 定义action行为

    新建studentActions.js,定义具体的行为。

    //studentActions.js
    import actionType from "./actionType";
    import {createActions} from "redux-actions";
    
    export default createActions({
        [actionType.GET_STUDENT_LIST]:()=>{},
        [actionType.ADD_STUDENT_LIST]:(student)=>{return student},
    })
    

    调用redux-actions的API函数createActions。使用方式如下:

    createActions({
      [action.type]:()=>{},
      [action.type]:(value1)=>{ return value2 }
    })
    

    三个知识点:

    1. 定一个无传参和返回的行为[action.type]:()=>{}
    2. 定一个无传参和返回的行为[action.type]:(value1)=>{return value2}
    3. createActions会返回action,如action.type='get_student_list',则返回action对象getStudentList(去掉下划线,驼峰结构),供组建调用

    步骤四 定义reducer

    新建reducer.js,监听action的行为并定义对应action的函数

    //reducer.js
    import {handleActions} from "redux-actions";
    import actionType from "./actionType";
    
    const defaultState = {
        students:[{name:'默认',age:0}]
    }
    
    export default handleActions({
        [actionType.GET_STUDENT_LIST]:(state, action)=>{
            const students = [{name:'张同学',age:19},{name:'李同学',age:19},{name:'王同学',age:19}]
            return {
                ...state,
                students:students
            }
        },
        [actionType.ADD_STUDENT_LIST]:(state, action)=>{
            return {
                ...state,
                students: [...state.students, action.payload]
            }
        }
    },defaultState)
    

    1.定义默认的state,作为store的返回值/默认值
    2.调用redux-actions的API函数handleActions来监听action和对应action的操作,基本调用方式。

    handleActions(
        {
            [action.type]:(state, action)=>{ return {...state, key:value}}
        }, 
      defaultState)
    

    action行为定义: [action.type]:(state, action)=>{ return {...state, key:value}}
    默认state的赋值:defaultState
    3.action.payload:固定搭配使用,action.js定义的具体action的返回值[actionType.ADD_STUDENT_LIST]:(student)=>{return student},payload=studeng

    步骤五

    reducer的定义

    //index.js
    import React from 'react';
    import ReactDOM from 'react-dom';
    import './index.css';
    import App from './App';
    import {Provider} from "react-redux";
    import store from "./store";
    
    ReactDOM.render(
        <Provider store={store}>
            <App/>
        </Provider>,
    
        document.getElementById('root')
    );
    

    在根的index.js外层包裹 <Provider store={store}>,这样实现react-redux的监听

    App.js使用

    //App.js
    import React from 'react'
    import studentActions from "./store/studentActions";
    import {connect} from "react-redux";
    
    class App extends React.Component {
        constructor(props) {
            super(props);
            this.props.getStudentList()
            this.studentName = React.createRef()
            this.studentAge = React.createRef()
        }
    
        addStudentBtn = () => {
            const name = this.studentName.current.value
            const age = parseInt(this.studentAge.current.value)
            const student = {name:name, age:age}
            this.props.addStudent(student)
        }
    
        render() {
            const {students} = this.props
            return (
                <div>
                    <p>学生信息
                        <ul>
                            {
                                students.map((student, index) => {
                                        return <li key={index}>姓名: {student.name} ;年龄:{student.age}</li>
                                    }
                                )
                            }
                        </ul>
                        <p>学生姓名
                            <input type="text" ref={this.studentName}/>
                        </p>
                        <p>学生年龄
                            <input type="text" ref={this.studentAge}/>
                        </p>
                        <p>
                            <button onClick={this.addStudentBtn}>添加</button>
                        </p>
                    </p>
                </div>
            )
        }
    }
    
    const mapStateToProps = (state) => {
        return {
            students: state.students
        }
    }
    
    export default connect(mapStateToProps, {
        getStudentList: studentActions.getStudentList,
        addStudent: studentActions.addStudentList,
    })(App)
    

    关注几个点:

    export default connect(mapStateToProps, {
        getStudentList: studentActions.getStudentList,
        addStudent: studentActions.addStudentList,
    })(App)
    

    1.mapStateToProps:函数定义了组建使用到的store的属性,如students: state.students,store的state.students赋值给当前控件的this.props. students

    {
        getStudentList: studentActions.getStudentList,
        addStudent: studentActions.addStudentList,
    }
    

    2.将createActions的action与组建的props进行关联
    getStudentList: studentActions.getStudentList:(studentActions.getStudentList)createActions会一个action名称,规则为去除下划线驼峰,并与当前控件的this.props.studentActions,使用this.props.getStudentList()即可调用

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