组件代码：
wxs.vue:

<template>
  <div id="wxs-popup" v-if="showPopup">
    <div :class="['showToast','wxs-' + params.icon]" v-if="params.show=='toast'">
      <span>{{params.title}}</span>
    </div>
    <div class='showModal' v-else-if="params.show=='modal'">
      <div class='modalBox'>
        <div class='modalMsg'>
          <h3>{{params.title}}</h3>
          <div class='text'>{{params.content}}</div>
        </div>
        <div class='modalBtn bordert'>
          <button class='docancel' v-if="params.showCancel" @click="closeModal({'cancel':true})">{{params.cancelText}}</button>
          <button class='doconfirm'  @click="closeModal({'confirm':true})">{{params.confirmText}}</button>
        </div>
      </div>
    </div>
    <div class='showWindow' v-else-if="params.show=='window'">
      <div class='winBox'>
        <span class='closeWin' @click="hideWindow" v-if="params.showClose"></span>
        <div class="winContent" v-html="params.innerHtml"></div>
      </div>
    </div>
  </div>
</template>
<style lang="scss">
#wxs-popup{
  width: 100%;
  max-width:750px;
  height: 100%;
  position: fixed;
  top: 0px;
  left: 0px;
  right: 0px;
  bottom: 0px;
  z-index: 300;
  font-size: 14px;
  line-height:130%;
  text-align:center;
  div{
    span{
      height:46px;
      display:flex;
      display:-webkit-flex;
      align-items:center;
      justify-content:center;
      overflow:hidden;
    }
  }
}

/* showToast */
.showToast{
  border-radius:6px;
  -webkit-border-radius:6px;
  -moz-border-radius:6px;
  padding:72px 12px 0px;
  width:102px;
  height:54px;
  position:fixed;
  top:48%;
  left:50%;
  margin:-63px 0px 0px -63px;
  position:fixed;
  z-index:400;
  color:#fff;
}
.wxs-loading{
  background:url(../../assets/ajax-loader.gif) no-repeat center 32px #000;
  background-size:32px 32px;
  opacity:0.72;
}
.wxs-success{
  background:url(../../assets/icon_success.png) no-repeat center 22px;
  background-size:50px;
  background-color:rgba(0,0,0,0.72);
}
.wxs-fail{
  background:url(../../assets/icon_fail.png) no-repeat center 22px;
  background-size:50px;
  background-color:rgba(0,0,0,0.72);
}
.wxs-none{
  background-color:rgba(0,0,0,0.72);
  border-radius:6px;
  padding:6px 18px;
  width:auto;
  min-width:120px;
  height:46px;
  position:fixed;
  top:49%;
  left:50%;
  margin:0px auto;
  display:block;
  -webkit-transform: translate(-50%,-50%);
  -moz-transform: translate(-50%,-50%);
  transform:translate(-50%,-50%);
  font-size:15px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* showWindow */
.showWindow,.showModal{
  width:100%;
  height:100%;
  background-color:rgba(0,0,0,0.6);
  display:flex;
  display:-webkit-flex;
  flex-direction:column;
  justify-content:center;
  align-items:center;
}

.showWindow .winBox, .showModal .modalBox {
  width:auto;
  height:auto;
  max-width:88%;
  max-height:88%;
  min-width:200px;
  min-height:200px;
  box-sizing:border-box;
  background:#fff; 
  color:#333; 
  position:relative;
  box-shadow: 0px 0px 6px #666; 
  border-radius:4px;
  margin-bottom:10px;
}

.showWindow{
  .winBox{
    .closeWin{
      position:absolute;
      width:32px;
      height:32px!important;
      background:url(../../assets/mobile_close.jpg) no-repeat center #fff;
      background-size:45%;
      box-shadow: 0 0 3px #888888; 
      border-radius:50%;
      right:-16px;top:-16px;
      cursor:pointer
    }
    .winContent{
      width:100%;
    }
    img{
      max-width:250px;
    }
  }
}

/* showModal */
.showModal{
  .modalBox{
    width:328px;
    min-width:inherit;
    height:190px;
    min-height:inherit;
  }
  .modalMsg{
    height:88px;
    padding:26px 20px 17px; 
    text-align:center;
    font-size:16px;
    color:#999; 
    line-height:150%;
    h3{
      font-size:18px; 
      text-align:center;
      margin-bottom:15px;
      color:#131114;
    }
  }
  .modalBtn{
    text-align:center;
    padding:12px 30px 11px;
    font-size:0px;
    button{
      height:33px;
      line-height:27px;
      width:50%;
      color:#576B95; 
      font-size: 18px; 
      vertical-align: top;
      margin:0px auto;
      border:none; 
      background:none;
    }
  }
}
</style>
<script>
  export default {
  	data: function() {
  	  return {}
  	},
    props: {
      showPopup: {
        type: Boolean,
        default: false
      },
      params:{
        type: Object,
        default: ()=> {
          return {}
        }
      }
    },
    methods: {
      execute: function(res){
        if(JSON.stringify(this.params) === "{}") return //防止重复执行
        try {
          typeof this.params.success === "function" && this.params.success(res)
        } catch(err) {
          typeof this.params.fail === "function" && this.params.fail(err)
        }
        typeof this.params.complete === "function" && this.params.complete(res);
        [this.params, this.showPopup] = [{}, false]
        this.$emit("status", false)
      },
      hideWindow: function(e) {
        this.execute(e)
      },
      closeModal: function(e) {
        this.execute(e)
      }
    },
    mounted: function() {
      //......
    },
    watch: {
      'showPopup' (to, from) {
        if(to) {
          if(this.params.show == "toast" && this.params.icon != "loading"){
            setTimeout(this.execute, this.params.duration)
          }
        } else if (!to && to != from) {
          this.execute()
        }
      }
    }
  }  
</script>

wxs.js:

/*
 * 仿微信小程序提示框、对话框、弹窗
 * created by maoeye
 */
import wxsComponent from './wxs' //引入组件
const baseWxs = {
  install: function(Vue, options) {
  	// 创建构造器
  	const vueComponent = Vue.extend(wxsComponent) 
  	let wxsPopup
  	const initmyComponent = function() {
      wxsPopup = new vueComponent({
      	el: document.createElement("div")
      })
      document.body.appendChild(wxsPopup.$el);
  	}
    
    Vue.prototype.$wxs = {
      options: {
        status: false,  //true 表示已有样式执行,
        show: ""        //表示执行的哪个样式
      },
      init: function(params, options) {
        const self = this;
        if(!wxsPopup) {

          //初始化
      	  initmyComponent() 
          
          //通过$on来接收子组件的传值
          wxsPopup.$on("status", function(data) {
        	  self.options.status = data
          })
        }
        for(var i in options){
          params[i] = options[i];
        }
        return params;
      },
      showToast: function(options){
      	this.options.status = true
      	this.options.show = "toast"
        let params = {
          show: this.options.show,
          title: '加载中',
          icon: 'loading',
          duration: 1500,
          //success: function (res) {},
          //fail: function (res) {},
          //complete: function (res) {}
        }
        this.init(params, options)
        wxsPopup.params = params
        wxsPopup.showPopup = true
      },
      hideToast: function(options) {
        if(!this.options.status || this.options.show!="toast") return;
        wxsPopup.showPopup = false
      },
      showWindow: function(options) {
        if(this.options.status) return
        this.options.status = true
      	this.options.show = "window"
        let params = {
          show: this.options.show,
          showClose: true,
          innerHtml: ""
        }
        this.init(params, options)
        wxsPopup.params = params
        wxsPopup.showPopup = true
      }
      showLoading: function(options) {
        if(options && options.icon){
          options.icon = "loading"
        }
        this.showToast(options)
      },
      hideLoading: function(options) {
      	this.hideToast(options);
      },
      showModal: function(options){
        if(this.options.status) return
        this.options.status = true
      	this.options.show = "modal"
        let params = {    
          show: this.options.show,
          title: '提示',
          content: '',
          showCancel: true,        
          cancelText: '取消',
          confirmText: '确认'
        }
        this.init(params, options);
        wxsPopup.params = params
        wxsPopup.showPopup = true
      }
    }
  }
}
export default baseWxs

main.js 引入：

import wxs from '@/components/wxs.js'
Vue.use(wxs)

使用示例：

Loading 提示框:
唤起Loading：
this.$wxs.showLoading({
  title: "加载中"
})
关闭Loading：
this.$wxs.hideLoading()

消息提示框：
this.$wxs.showToast({
  title: "加载成功",
  icon: "success", //success 成功，fail 失败
  duration: 1500, 
  success: function(res) { ...... },
  fail: function(res) { ...... },
  complete: function(res) { ...... }
})

模态对话框:
this.$wxs.showModal({
  title: "提示",
  content: '请输入用户名或密码',
  showCancel: true, // true 显示cancal按钮       
  cancelText: '取消',
  confirmText: '确认',
  success: function (res) { ...... },
  fail: function (res) { ...... },
  complete: function (res) { ...... }
})

模拟弹窗：
this.$wxs.showWindow({
  showClose: true, // true 显示close按钮
  innerHtml: "<div> ...... </div>"
})

github地址：https://github.com/283301717/loading