<template>
 <div id="app">
 这是一个空的app
 </div>
</template>

<script>
 export default {
  name : 'app'
 }
</script>

import Vue from 'vue'
import Router from 'vue-router'

Vue.use(Router)

export default new Router({
 routes: [
  {
   path: '/',
  }
 ]
})

import Vue from 'vue'
import App from './App'
import router from './router'
import Vuex from 'vuex'
import store from './vuex/store'

Vue.use(Vuex)

Vue.config.productionTip = false

/* eslint-disable no-new */
new Vue({
 el: '#app',
 router,
 store,
 template: '<App/>',
 components: { App }
})

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

const store = new Vuex.Store({
 state: {
  userName : 'ghostwu'
 }
})

export default store

<template>
  <div>
    <h3>{{myName}}</h3>
  </div>
</template>
<script>
  export default {
    name : "Main",
    computed : {
      myName (){
        return this.$store.state.userName;
      }
    }
  }
</script>

<template>
 <div id="app">
  <Mainc></Mainc>
 </div>
</template>

<script>
import Mainc from './components/Main.vue';
export default {
 name: 'app',
 components : {
  Mainc
 }
}
</script>

<template>
  <div>
    <input type="text" v-model="msg" />
    <input type="button" v-on:click="setName" value="点我" />
  </div>
</template>
<script>
  export default {
    name : 'Header',
    data(){
      return {
        msg : ''
      }
    },
    methods : {
      setName(){
        this.$store.state.userName = this.msg;
      }
    }
  }
</script>

<template>
 <div id="app">
  <Headerc></Headerc>
  <Mainc></Mainc>
 </div>
</template>

<script>
import Headerc from './components/Header.vue';
import Mainc from './components/Main.vue';
export default {
 name: 'app',
 components : {
  Headerc,
  Mainc
 }
}
</script>

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

const store = new Vuex.Store({
 state: {
  userName : 'ghostwu'
 },
 mutations : {
  showUserName( state, msg ){
   state.userName = msg;
  }
 }
})

export default store

<template>
  <div>
    <input type="text" v-model="msg" />
    <input type="button" v-on:click="setName" value="点我" />
  </div>
</template>
<script>
  export default {
    name : 'Header',
    data(){
      return {
        msg : ''
      }
    },
    methods : {
      setName(){
        this.$store.commit( 'showUserName', this.msg );
      }
    }
  }
</script>