React-Native项目中使用Redux

Bertha 。 2023-07-04 15:49 1阅读 0赞

### 前言 ###

网上别人的文档都是 直接 就是上`redux` `redux-thunk` `react-redux` ,`immutable`这样的一套,这个有经验的看还行,新手看就很吃力了,需要了解一步一步的安装redux达到开发要求

我觉得这需要一个学习的过程,拔苗助长不是好事

这是我写项目的逐步搭建的过程,欢迎查看源代码[github-pinduoduo][]

## Redux ##

1.  安装redux(后面再安装(react-redux)

> 因为`redux`是js的部分 所以不需要link

npm install redux--save

安装完成后确认可以正常启动

1.  创建store

我的项目结构

![format_png][]

和React项目一样的项目结构

index.js

import { createStore } from 'redux'
    import reducer from './reducer'
    
    export default createStore(reducer) // 导入state

reducer.js

import actionTypes from './actionTypes'
    const defaultState = { // 初始化state
      data: 'my is redux!!!!' 
    }
    
    export default (state = defaultState, action) => {
      console.log(action)
      if (action.type == actionTypes.CHANGE) { // 修改state
        const newState = JSON.parse(JSON.stringify(state))
        newState.data = 'change data!!!'
        return newState
      }
      return state
    }

actionTypes.js

export default {
      CHANGE: 'change' // 定义统一的type
    }

actionCreators.js

import actionTypes from './actionTypes'
    export function change() { // 统一管理action
      return {
        type:  actionTypes.CHANGE
      }
    }

最后在页面里面

import React, { Component } from 'react'
    import {
      Text,
      StyleSheet,
      View,
      StatusBar,
      Dimensions,
      Button
    } from 'react-native'
    import store from '../../../store/index' // 导入store
    import { change } from '../../../store/actionCreators'  // 导入action
    export default class Popular extends Component {
      constructor(props) {
        super(props)
        this.state = store.getState() // 初始化state,获取redux里面数据
        store.subscribe(() => { // 订阅state的改变
          this.setState(store.getState())
        }) 
      }
      render() {
        return (
          <View>
            <Text>{this.state.data}</Text>
            <Button
              title="更新state"
              onPress={() => {
                store.dispatch(change())
              }}
            />
            <Button
              title="查看state"
              onPress={() => {
                console.log(store.getState())
              }}
            />
          </View>
        )
      }
    }
    
    const styles = StyleSheet.create({})

最基础的`redux`就使用成功了,但是这个还达不到我们的开发要求,下面将引入`react-redux`

## Redux + React-redux ##

> 如果不了解`React-redux`,请学习后再说,不然肯定看不懂,[React-redux文档][React-redux]

[React-redux文档][React-redux 1]

之前我们在组件里面使用Redux直接去获取数据,加入每个页面都这样写,会很麻烦,所以我们要借助`react-redux`来帮我们处理store

修改之前写的页面代码,去掉之前页面使用`state`的地方

import React, { Component } from 'react'
    import {
      Text,
      StyleSheet,
      View,
      StatusBar,
      Dimensions,
      Button
    } from 'react-native'
    import { change } from '../../../store/actionCreators'
    class Popular extends Component {
      render() {
        return (
          <View>
            <Text>{this.props.data}</Text>
            <Button title="更新state" onPress={() => {
                //..
              }} />
            <Button
              title="获取state"
              onPress={() => {
                //..
              }}
            />
          </View>
        )
      }
    }
    
    const styles = StyleSheet.create({})
    
    export default Popular

修改程序的挂载入口

index.js

/** @format */
    import React, { Component } from 'react'
    import { Provider } from 'react-redux'
    import { AppRegistry } from 'react-native'
    import store from './app/store'
    import App from './app/routes/App'
    import { name } from './app.json'
    
    class Apps extends Component {
      render() {
        return (
           // 挂载store,让app内部所有组件都可以使用
          <Provider store={store}>
            <App />
          </Provider>
        )
      }
    }
    
    AppRegistry.registerComponent(name, () => Apps)

这里我们就可以在组件里面通过`connent`来接收了

import React, { Component } from 'react'
    import { connect } from 'react-redux'
    import {
      Text,
      StyleSheet,
      View,
      StatusBar,
      Button
    } from 'react-native'
    import { change } from '../../../store/actionCreators'
    class Popular extends Component {
      render() {
        return (
          <View>
            <StatusBar
              translucent={true} // 设置沉浸式状态栏 正常情况下 状态栏高度为20 这里的20 需要页面元素距离最上面 paddingTop:20
              backgroundColor={'rgba(0,0,0,0.1)'} // 设置状态栏颜色
              animated={true} // 允许动画切换效果
            />
            <Text>{this.props.data}</Text>
            <Button title="更新state" onPress={this.props.changeData} />
            <Button
              title="获取state"
              onPress={() => {
                console.log(this.props.data)
              }}
            />
          </View>
        )
      }
    }
    
    const styles = StyleSheet.create({})
    
    const mapState = state => ({
      data: state.data
    })
    
    const mapDispatch = dispatch => ({
      changeData() {
        dispatch(change())
      }
    })
    
    export default connect(
      mapState,
      mapDispatch
    )(Popular)

这里我们`React-redux`再次获取并修改了redux里面的数据,相对之下,使用`React-redux`后,页面逻辑更加清楚

## Redux + React-redux+immutable ##

[immutable][]在日常开发里面很常见,让我们的数据更加严谨

很简单,首先安装

npm install immutable

处理我们store的数据

import actionTypes from './actionTypes'
    import {fromJS} from 'immutable' 
    const defaultState = fromJS({ // 将对象转成immutable对象
      data: 'my is redux!!!!'
    })
    
    export default (state = defaultState, action) => {
      if (action.type == actionTypes.CHANGE) {
        return state.set('data','change Redux!!!')
      }
      return state
    }

然后处理我们页面里面引用数据的地方

const mapState = state => ({
      data: state.get('data') // immutable对象使用get获取
    })

## redux的分离 ##

将大量的store数据放在一起是非常不好的行为,我们要将每个组件之间的`store`尽可能的分离

> 这里用的是redux给我们提供的 combineReducers 将store进行合并

修改页面目录结构,在页面目录里面创建store

![format_png 1][]

组件内部的sore代码

**Popular/store/reducer**

import actionTypes from './actionTypes'
    import {fromJS} from 'immutable'
    const defaultState = fromJS({
      data: 'my is redux!!!!'
    })
    
    export default (state = defaultState, action) => {
      if (action.type == actionTypes.CHANGE) {
        return state.set('data','change Redux!!!')
      }
      return state
    }

**Popular/store/actionTypes**

export default {
      CHANGE: 'change'
    }

**Popular/store/actionCreators**

import actionTypes from './actionTypes'
    export function change() {
      return {
        type:  actionTypes.CHANGE
      }
    }

**Popular/store/index**

import reducer from './reducer'
    import actionCreators from './actionCreators'
    import actionTypes from './actionTypes'
    
    export { reducer, actionCreators, actionTypes }
    // 使用入口

这样我们就在组件内部新建了一个store,接下来我们要把组件内部的store合并store里面

**./store/reducer**

import { combineReducers } from 'redux'
    import { reducer as homePopular } from '../src/home/Popular/store/index'
    
    export default combineReducers ({
      homePopular: homePopular
    })

这就完成了store的合并,这里store变了,自然访问就变了

**Popular.js**

const mapState = state => ({
      data: state.homePopular.get('data')
    })

## 最后引入`redux`中间件 ##

> 我一般情况下使用`redux-thunk`

npm install redux-thunk

import { createStore,applyMiddleware } from 'redux'
    import thunk from 'redux-thunk'
    import reducer from './reducer'
    
    
    export default createStore(
      reducer,
      applyMiddleware(thunk)
    )

这里不做样式了,会的人自然会,不会的学习一下,学会使用很简单

[github-pinduoduo]: https://github.com/vkcyan/RN-code
[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWdzLml0eHVleXVhbi5jb20vRnRQdTBRdHN1LXlLUWxGWE8wbnRzbUpLT2xIQy5wbmc?x-oss-process=image/format,png
[React-redux]: https://article.itxueyuan.com/EbmWQ
[React-redux 1]: https://cn.redux.js.org/docs/react-redux/
[immutable]: https://facebook.github.io/immutable-js/
[format_png 1]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWdzLml0eHVleXVhbi5jb20vRmtmYmJDYkxtVWpuN3RaOFhaamJad21oS2V4cS5wbmc?x-oss-process=image/format,png