create-react-app mydemo

npm run eject

npm i redux --save

const Add = 'addGirl', Remove = "removeGirl";
export function reducer(state = 0, action) {
  switch (action.type) {
    case Add:
      return state + 1;
    case Remove:
      return state - 1;
    default:
      return 10;
  }
}

//action creator,把action封装成一个方法，这样用的时候不用每次定义，避免出错
export function addCreator() {
  return { type: Add };
}
export function removeCreator() {
  return { type: Remove };
}

export function addAsync() {
  return (dispatch, getState) => {
    setTimeout(function () {
      dispatch(addCreator());
    }, 1000);
  }
}

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import registerServiceWorker from './registerServiceWorker';
import { createStore } from 'redux';
import thunk from 'redux-thunk';
import { reducer,addCreator,removeCreaator } from './index.redux';
import { Provider } from 'react-redux'
const store = createStore(reducer);
function render() {
  ReactDOM.render(
    <App store={store} addCreator={addCreator} removeCreator={removeCreator} />,
    document.getElementById('root')
  );
}
//封装成方法，方便下面的store的订阅调用
render();
//每当dispatch时，订阅的函数就会执行
store.subscribe(render);
registerServiceWorker();

import React, { Component } from 'react';
import './App.css';
class App extends Component {
 render() {
  var store=this.props.store;
  var num=store.getState();
  return (
   <div className="App">
    <h1>现在有机关枪{this.props.num}把。</h1>
    <button onClick={() => { store.dispatch(this.props.addCreator()) }}>add</button>
    <button onClick={() => { store.dispatch(this.props.removeCreator()) }}>remove</button>
   </div >
  );
 }
}
export default App;

npm i react-thunk --save

import thunk from 'redux-thunk';

const store = createStore(reducer, applyMiddleware(thunk));

export function addAsync() {
  return (dispatch, getState) => {
    setTimeout(function () {
      dispatch(addCreator());
    }, 1000);
  }
}

<button onClick={() => { store.dispatch(this.props.addAsync()) }}>addAsync</button>