效果图：

 

DOM部分：

子组件，也就是封装的Dialog.vue

DOM部分：

<template>
  <transition name="fade">
    <div class="dialog-wrap" v-show="showMask">
      <div class="dialog-mask"></div>
      <div class="dialog">
        <div class="title">
          登陆
          <span class="close" @click="closeModule">X</span>
        </div>
        <div class="input">
          <el-input placeholder="请输入您的UID" v-model="uid" clearable></el-input>
        </div>
        <div class="login-helper">
          <p data-v-7b4b534a class="help">
            1、请
            <a
              data-v-7b4b534a
              href="http://music.163.com"
              target="_blank"
            >点我(http://music.163.com)</a>打开网易云音乐官网
          </p>
          <p class="help">2、点击页面右上角的“登录”</p>
          <p class="help">3、点击您的头像，进入我的主页</p>
          <p class="help">4、复制浏览器地址栏 /user/home?id= 后面的数字（网易云 UID）</p>
        </div>
        <div class="login-button">
          <span>登陆</span>
        </div>
      </div>
    </div>
  </transition>
</template>

Script部分：

<script>
export default {
  props: ['showMask'],  // 接收父组件传递过来的showMask，控制Dialog对话框的显示与隐藏
  data() {
    return {
      uid: null
    };
  },
  methods: {
    closeModule() {
      this.$emit('close'); // 点击X号，向父组件触发close事件
    }
  }
};
</script>

样式部分：

@import '@/style/variables.scss';
@import '@/style/mixin.scss';
.dialog-wrap {
  position: absolute;
  z-index: 100;
  &.fade-enter-active,
  &.fade-leave-active {
    transition: opacity 0.5s;
  }
  &.fade-enter,
  &.fade-leave-to {
    opacity: 0;
  }
  .dialog {
    position: fixed;
    @include same-wh(25rem);
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    // background-color: #202020;
    background-color: #202020;
    z-index: 100;
    padding: 2.142857rem 1.428571rem;
    .title {
      position: relative;
      color: #ffffff;
      margin-bottom: 1.785714rem;
      .close {
        position: absolute;
        top: 0;
        right: 0;
        @include same-wh(2rem);
        text-align: center;
        line-height: 2rem;
        cursor: pointer;
        border-radius: 50%;
        background-color: rgba($color: #000000, $alpha: 0.8);
      }
    }
    .input {
      margin-bottom: 1.142857rem;
      .el-input__inner {
        background-color: #4b4b4b;
        font-size: 0.857143rem;
        border: 0;
        color: #b0b0b0;
      }
    }
    .login-helper {
      line-height: 1.428571rem;
      margin-bottom: 0.714286rem;
      color: #b0b0b0;
      .help {
        margin-bottom: 8px;
      }
    }
    .login-button {
      padding: 0.714286rem 1.428571rem;
      margin-top: 1.785714rem;
      border-radius: 0.357143rem;
      text-align: center;
      color: #ffffff;
      background-color: $theme-color;
      cursor: pointer;
    }
  }
　　// 后面的遮挡层
  .dialog-mask {
    position: fixed;
    z-index: 100;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba($color: #000000, $alpha: 0.6);
  }
}

父组件使用：

DOM部分：

<div class="show-mask">
　　　　// 监听子组件触发的close事件
      <Dialog @close="closeLoginModule" :showMask="showMask"></Dialog>
</div>

script部分：

export default {
  components: {
    Dialog
  },
  data() {
    return {
      showMask: false
    };
  },
  methods: {
    openLoginModule() {
      this.showMask = true;
    },
　　// 关闭对话框
    closeLoginModule() {
      this.showMask = false;
    }
  }
};