对React Native中Reduce理解

React Native Redux学习

1.action
进行一定的逻辑,并将处理后的结果,使用dispatch以type的形势传递出去,结果在reduce里面处理结果
2.reducers
接受Action里面传出的type,根据type的类型更改state的值并将值返回给
3.store
进行配置store,在程序的入口中调用,调用后reduce更新的state就会传送到store中
store会更具传回的state改变页面显示
使用:
在需要使用的页面中使用react-redux中的connect与store进行连接,

/**
*在select中设置需要的state
**/
function select(store){
return {

isLoggedIn: store.userStore.isLoggedIn,user: store.userStore.user,

}
}
//页面与store链接
export default connect(select)(Main);

使用步骤:
1.在项目中导入包
1>.导入react-redux
2>导入redux
3>导入redux-thunk
4>导入redux-persist
2.创建文件目录
redux中使用的:
1>.actions
2>.store
3>.reducers

3.创建相关文件

1>.在store目录下创建index.js

import { applyMiddleware,createStore } from 'redux';
import thunk from 'redux-thunk';
import { persistStore,autoRehydrate } from 'redux-persist';
import { AsyncStorage } from 'react-native';
import reducers from '../reducers';

const logger = store => next => action => {
  if(typeof action === 'function') console.log('dispatching a function');
  else console.log('dispatching',action);
  let result = next(action);
  console.log('next state',store.getState());
  return result;
}

let middlewares = [
  logger,thunk
];

let createAppStore = applyMiddleware(...middlewares)(createStore);

export default function configureStore(onComplete: ()=>void){
  const store = autoRehydrate()(createAppStore)(reducers);
    let opt = {
      storage: AsyncStorage,transform: [],//whitelist: ['userStore'],};
  persistStore(store,opt,onComplete);
  return store;
}

2.创建入口文件,入口文件中使用react-redux中的Provider,在Provider中使用store

import React,{ Component } from 'react';
//导入provider
import { Provider } from 'react-redux';
//导入store中的configureStore
import configureStore from './store/index';

let store = configureStore();

import Root from './root';

export default class App extends Component{
constructor(){

super();
  this.state = {
    isLoading: true,store: configureStore(()=>{this.setState({isLoading: false})})
  }

}
render(){

if(this.state.isLoading){
    console.log('loading app');
    return null;
  }

/**
*
*使用store
*
**/

return (
    <Provider store={this.state.store}>
        <Root />
    </Provider>
  )

}
}

3.创建Action
创建action文件

import * as TYPES from './types';

// fake user data
let testUser = {
'name': 'juju',
'age': '24',
'avatar': 'https://avatars1.githubuserco...'
};

// for skip user
let skipUser = {
'name': 'guest',
'age': 20,
'avatar': 'https://avatars1.githubuserco...',
};

// login
export function logIn(opt){
return (dispatch) => {

dispatch({'type': TYPES.LOGGED_DOING});
  let inner_get = fetch('http://www.baidu.com')
    .then((res)=>{
        dispatch({'type': TYPES.LOGGED_IN,user: testUser});
    }).catch((e)=>{
        AlertIOS.alert(e.message);
        dispatch({'type': TYPES.LOGGED_ERROR,error: e});
    });

}
}

// skip login
export function skipLogin(){
return {

'type': TYPES.LOGGED_IN,'user': skipUser,

}
}

// logout
export function logOut(){
return {

'type': TYPES.LOGGED_OUT

}
}

4.在页面js中调用action

//将action导入页面,就可以从页面文件中使用action中的方法
import { logIn,skipLogin } from '../actions/user';

reduce运行路线
配置store-->入口使用store

页面中调用action->action将type发出去间接调用reduce->页面中使用connect将页面的state和store

（编辑：李大同）

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