介绍一下我在之前项目中是如何使用redux的。
redux学习：http://www.ruanyifeng.com/blog/2016/09/redux_tutorial_part_one_basic_usages.html
http://www.ruanyifeng.com/blog/2016/09/redux_tutorial_part_two_async_operations.html
http://www.ruanyifeng.com/blog/2016/09/redux_tutorial_part_three_react-redux.html
阮一峰老师已经在这几篇文章里讲解的很清楚了，我就不班门弄斧了，这里只是说明一下在项目中的使用。
首先，安装
redux：Redux
react-redux：Redux的作者封装的React专用库
redux-logger：日志中间件，用于调试
redux-persist：缓存
redux-thunk：支持异步dispatch
安装方法，在package.json文件中的dependencies中添加以下各项
"react-redux": "^5.0.1",
"redux": "^3.6.0",
"redux-logger": "^2.7.4",
"redux-persist": "^4.0.1",
"redux-thunk": "^2.1.0"
然后，执行npm install即可
也可以分开安装，例如，安装redux
npm install --save redux （--save代表修改package.json中的dependencies，关于npm的使用可以自行百度，给一个菜鸟教程的链接：http://www.runoob.com/nodejs/nodejs-npm.html）
准备工作完毕后，首先从store开始，新建一个文件，添加以下代码：
import {applyMiddleware, createStore} from 'redux';
import thunk from 'redux-thunk';
import createLogger from 'redux-logger';
import {persistStore, autoRehydrate} from 'redux-persist';
import {AsyncStorage} from 'react-native';
import reducers from '../reducers/index'; //后面解释这个
const logger = createLogger();
let middlewares = [
thunk,
logger
];
//解释一下这个写法的意思，可以查看源码，看到applyMiddleware函数，可以传递参数‘{...Function} middlewares The middleware chain to be applied’，然后返回一个以createStore函数为参数的函数，最后会返回一个和createStore函数参数相同的函数，即createAppStore实际是一个function (reducer, preloadedState, enhancer)，且这个函数中持有传入的createStore函数，说了一堆函数可能有点乱，其实就是几个闭包
let createAppStore = applyMiddleware(...middlewares)(createStore);
export default function configureStore(onComplete: ()=>void){
//同样的查看autoRehydrate，会看到这个函数结构基本和applyMiddleware一样，所以生成store的过程有很多种写法，其实最后得到的结果是一样
const store = autoRehydrate()(createAppStore)(reducers);
let opt = {
storage: AsyncStorage,
transform: [],
whitelist: [],
blacklist: []
};
persistStore(store, opt, onComplete);
return store;
}
下面实现创建store时用到的reducers，随着项目的增大，reducer会有很多，所以可以将其进行划分，最后合并到一起。例如这里新建一个price.js的reducer文件，在文件中如此实现：
//数据结构因业务所定
const initialState = {
datas: null,
status: null,
netMsg: null,
price: null
};
import {Net, Process, Response} from '../net/net';
import Type from '../actions/type';
export default function priceReducer(state=initialState, action){
switch(action.type){
case Type.GETPRICEBASEDATA:
{
switch (action.name) {
case Process.FETCH_BEGIN:
return {
...state,
status: Process.FETCH_BEGIN,
price: null
};
case Process.FETCH_SUCCESS:
return {
...state,
datas: action.payload,
status: Process.FETCH_SUCCESS,
netMsg: action.msg
};
case Process.FETCH_FAIL:
return {
...state,
status: Process.FETCH_FAIL,
netMsg: action.msg
};
default:
return state;
}
}
case Type.CALCULATEPRICE:
{
switch (action.name) {
case Process.FETCH_BEGIN:
return {
...state,
status: Process.FETCH_BEGIN
};
case Process.FETCH_SUCCESS:
return {
...state,
price: action.payload,
status: Process.FETCH_SUCCESS,
netMsg: action.msg
};
case Process.FETCH_FAIL:
return {
...state,
status: Process.FETCH_FAIL,
netMsg: action.msg
};
default:
return state;
}
}
default:
return state;
}
}
同理新建其它reducer，然后在reducers.js文件中合并
import { combineReducers } from 'redux';
import serviceReducer from './service';
import priceReducer from './price';
import answersReducer from './answers';
export default combineReducers({
serviceStore: serviceReducer,
priceStore: priceReducer,
answersStore: answersReducer
});
然后实现action，同样action也应该划分实现，例如price.js的action如下：
import {Net, Process, Api, Response} from '../net/net';
import Type from './type';
const changePriceParams = (name, params) => (dispatch, getState) => {
return dispatch({type: Type.CHANGEPRICEPARAMS, name, params});
};
const calculatePrice = (params) => (dispatch, getState) => {
dispatch({type: Type.CALCULATEPRICE, name: Process.FETCH_BEGIN});
return Net.commonPostModel(Api.CALCULATEPRICEAPI, params, (res)=>{
if (res.code == 0 || res.code == 999) {
dispatch({type: Type.CALCULATEPRICE, name: Process.FETCH_SUCCESS, payload: res.data, msg: res.msg})//res.data
} else {
dispatch({type: Type.CALCULATEPRICE, name: Process.FETCH_FAIL, payload: null, msg: res.msg})
}
})
};
const getPriceBaseData = () => (dispatch, getState) => {
dispatch({type: Type.GETPRICEBASEDATA, name: Process.FETCH_BEGIN});
return Net.commonGetModel(Api.GETPRICEBASEDATAAPI, null, (res)=>{
if (res.code == 0 || res.code == 999) {
dispatch({type: Type.GETPRICEBASEDATA, name: Process.FETCH_SUCCESS, payload: res.data, msg: res.msg})//res.data
} else {
dispatch({type: Type.GETPRICEBASEDATA, name: Process.FETCH_FAIL, payload: null, msg: res.msg})
}
})
};
export {changePriceParams, calculatePrice, getPriceBaseData};
type.js表示action的标示
const Type = {
get GETSERVICEMAIN() {return 'GETSERVICEMAIN'},
get CHANGEPRICEPARAMS() {return 'CHANGEPRICEPARAMS'},
get GETPRICERULE() {return 'GETPRICERULE'},
get SWITCHSECTION() {return 'SWITCHSECTION'},
get GETPRICEBASEDATA() {return 'GETPRICEBASEDATA'},
get CALCULATEPRICE() {return 'CALCULATEPRICE'}
};
export default Type;
各部分定义完毕后，在根文件如下实现：
import React, { Component } from 'react';
import { Provider } from 'react-redux'; //Provider利用了context机制将store对象传递到各个子控件
import configureStore from './store/index';
let store = configureStore();
import Root from './root';
export default class App extends Component{
render(){
return (
)
}
}
在每个子控件中export时，如下写：
import { connect } from 'react-redux';
export default connect()(Root);
另外两个参数可选实现
import {changePriceParams, calculatePrice, getPriceBaseData} from '../actions/price';
//映射state到props，即获取时直接写this.props.price即可，不再使用this.state（不是不能用this.state，只是和react-redux的设计有悖）
const mapStateToProps = (state) => {
return {
params: state.priceStore.params,
datas: state.priceStore.datas,
status: state.priceStore.status,
netMsg: state.priceStore.netMsg,
price: state.priceStore.price
}
};
//映射dispatch到props，即使用时this.props.calculatePrice(...)即可
const mapDispatchToProps = (dispatch) => {
return {
changePriceParams: (name, text)=> {
dispatch(changePriceParams(name, text))
},
getPriceBaseData: ()=> {
dispatch(getPriceBaseData())
},
calculatePrice: (params)=> {
dispatch(calculatePrice(params))
}
}
};
export default connect(
mapStateToProps,
mapDispatchToProps
)(Price);
最后，在控件中即可如下使用：
render() {
if (this.props.status === Process.FETCH_BEGIN) {
showLoading(null);
this.loading = true;
} else if (this.props.status === Process.FETCH_FAIL && this.loading) {
showError(this.props.netMsg);
this.loading = false;
} else {
hideHUD();
}
return this._mainView();
}
在需要计算价格的地方，执行this.props.calculatePrice(params);即可。
调用相应action，然后传递至reducer修改store，然后更新界面，这些都会自动执行
这样UI可以专心UI，业务可以专心业务，数据存储专心存储，网络请求专心网络，完美分割。