本文共 3885 字,大约阅读时间需要 12 分钟。
首先我们得对redux有一定的基础认识。
import React from 'react';import ReactDOM from 'react-dom';import { Provider} from 'react-redux'import TodoList from './TodoList'import store from './store/index'ReactDOM.render(, document.getElementById('root'));
store就是保存数据的地方,可以把它看成一个容器,整个应用只能有一个store。
Redux 提供createStore
这个函数,用来生成 Store 代码块:
import { createStore, applyMiddleware } from 'redux'import thunk from 'redux-thunk'import { composeWithDevTools } from 'redux-devtools-extension'import reducers from './reducer'const store = createStore(reducers,composeWithDevTools(applyMiddleware(thunk)) )export default store
我把actions文件中的type抽离出来写成了一个新的文件 action-types.js
,用常量来定义type防止出错。
export const CHANGE_INPUTVALUE = 'change_input' //修改input框值export const DELETE_ITEM = 'delete_item' //删除export const ADD_ITEM = 'add_item' //添加
state的变化就会导致页面视图view的改变。但是,用户接触不到vstate,只能接触到view。 所以state的改变必须是view导致的,action就是view发出的通知,表示state要发生变化了。
代码:import { CHANGE_INPUTVALUE, DELETE_ITEM, ADD_ITEM} from './action-types'// export const inputChange = (e) => ({ type: CHANGE_INPUTVALUE, value: e.target.value })//定义同步actionexport const inputChange = (e) => dispatch => { dispatch({ type: CHANGE_INPUTVALUE, value: e.target.value}) }export const clickButton = () => ({ type: ADD_ITEM })export const deleteItem = (index)=>({ type: DELETE_ITEM,index})
reducer是一个纯函数。它接受action和当前state作为参数,返回一个新的state。
代码:// reducer里只能接受state,不能改变stateimport { combineReducers} from 'redux'import { CHANGE_INPUTVALUE, DELETE_ITEM, ADD_ITEM} from './action-types'const defaultState = { inputValue: 'write something', list: [ '金泰亨', '朴智旻', '金南俊' ]}// 产生list状态的reducerfunction list (state = defaultState, action){ if (action.type === CHANGE_INPUTVALUE) { let newState = JSON.parse(JSON.stringify(state)) newState.inputValue = action.value return newState } if (action.type === ADD_ITEM) { let newState = JSON.parse(JSON.stringify(state)) newState.list.push(newState.inputValue) newState.inputValue = '' return newState } if (action.type === DELETE_ITEM) { let newState = JSON.parse(JSON.stringify(state)) newState.list.splice(action.index, 1) return newState } return state}//向外暴露状态的结构export default combineReducers ({ list})
import React, { Component } from 'react'import { connect } from 'react-redux'import TodoListUI from './TodoListUI'import { inputChange,clickButton,deleteItem} from './store/actions' class TodoList extends Component { changeInputValue = (e) => { // console.log(e.target.value); this.props.inputChange(e) } clickBtn = () => { this.props.clickButton() } deleteItem = (index) => { this.props.deleteItem(index) } render() { return () }}export default connect( state =>({ list:state.list}), { inputChange,clickButton,deleteItem})(TodoList)
import React, { Component } from 'react';import 'antd/dist/antd.css'import { Input, Button, List } from 'antd'class TodoListUI extends Component { constructor(props) { super(props); this.state = { } } render() { return (); }} export default TodoListUI;(
{ this.props.deleteItem(index) }}> { item} )} />
至此,一个完整的todolist小案例就实现了。
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