<!--
 * 上传图片拖拽排序、底部显示图片原始名称
-->
<template>
  <div class="uploadWrapper">
    <vuedraggable
      class="vue-draggable"
      :class="{ single: isSingle, maxHidden: isMaxHidden }"
      v-model="imgList"
      tag="ul"
      draggable=".draggable-item"
      @start="onDragStart"
      @end="onDragEnd"
    >
      <!-- 拖拽元素 -->
      <li
        v-for="(item, index) in imgList"
        :key="item + index"
        class="draggable-item"
        :style="{ width: width + 'px', height: height + 'px' }"
      >
        <el-image :src="item" :preview-src-list="[item]"></el-image>
        <div class="shadow" @click="onRemoveHandler(index)">
          <i class="el-icon-delete"></i>
        </div>
        <div class="showBottom" v-if="showBottom">
            {{nameItams[item]}}
        </div>
      </li>
      <!-- 上传按钮 -->
      <el-upload
        slot="footer"
        ref="uploadRef"
        class="uploadBox"
        :style="{ width: width + 'px', height: height + 'px' }"
        :action="url"
        :headers="headers"
        accept=".JPG,.PNG,.JPEG,.GIF,.tif,.BMP"
        :show-file-list="false"
        :multiple="!isSingle"
        :limit="limit"
        :before-upload="beforeUpload"
        :on-success="onSuccessUpload"
        :on-exceed="onExceed"
      >
        <i class="el-icon-plus uploadIcon">
          <span class="uploading" v-show="isUploading">正在上传...</span>
          <span
            v-if="!isUploading && limit && limit!==99 && !isSingle"
            class="limitTxt"
          >最多{{ limit }}张</span>
        </i>
      </el-upload>
    </vuedraggable>
  </div>
</template>
 
<script>
import vuedraggable from 'vuedraggable' // 一款vue拖拽插件
import utils from './utils'
 
export default {
  name: 'ImgUpload',
  components: { vuedraggable },
  props: {
    // 上传地址
    url: {
      type: String,
      // default: 'https://jsonplaceholder.typicode.com/posts/'
      default: process.env.BASE_API + '/upload/uploadImage',
    },
    // 图片数据(图片url组成的数组) 通过v-model传递
    value: {
      type: Array,
      default () {
        return []
      }
    },
    // 限制上传的图片数量
    limit: {
      type: Number,
      default: 99
    },
    // 限制上传图片的文件大小(kb)
    size: {
      type: Number,
      default: 500
    },
    // 是否是单图上传(单图上传就是已传图片和上传按钮重叠)
    isSingle: {
      type: Boolean,
      default: false
    },
    // 是否使用图片压缩
    useCompress: {
      type: Boolean,
      default: false
    },
    // 图片显示的宽度(px)
    width: {
      type: Number,
      default: 100
    },
    // 图片显示的高度(px)
    height: {
      type: Number,
      default: 100
    },
    // 底部是否显示图片原始名称
    showBottom: {
      type: Boolean,
      default: true
    }
  },
 
  data () {
    return {
      headers: {},
      isUploading: false, // 正在上传状态
      isFirstMount: true, // 控制防止重复回显
      nameItams:{}
    }
  },
 
  computed: {
    // 图片数组数据
    imgList: {
      get () {
        return this.value
      },
      set (val) {
        if (val.length < this.imgList.length) {
          // 判断是删除图片时同步el-upload数据
          this.syncElUpload(val)
        }
        // 同步v-model
        this.$emit('input', val)
      }
    },
    // 控制达到最大限制时隐藏上传按钮
    isMaxHidden () {
      return this.imgList.length >= this.limit
    }
  },
 
  watch: {
    value: {
      handler (val) {
        if (this.isFirstMount && this.value.length > 0) {
          this.syncElUpload()
        }
      },
      deep: true
    }
  },
 
  mounted () {
    if (this.value.length > 0) {
      this.syncElUpload()
    }
  },
 
  methods: {
    // 同步el-upload数据
    syncElUpload (val) {
      const imgList = val || this.imgList
      this.$refs.uploadRef.uploadFiles = imgList.map((v, i) => {
        return {
          name: 'pic' + i,
          url: v,
          status: 'success',
          uid: utils.createUniqueString()
        }
      })
      this.isFirstMount = false
    },
    // 上传图片之前
    beforeUpload (file) {
      this.isFirstMount = false
      if (utils.validImgUpload(file, this.size)) {
        this.isUploading = true
        return true
      } else {
        return false
      }
    },
    // 上传完单张图片
    onSuccessUpload (res, file, fileList) {
        if (res.code === 200) {
          console.log("上传文件-> ",file);
          this.nameItams[res.data.url] = file.name;
          if (this.imgList.length < this.limit) {
            this.imgList.push(res.data.url)
          }
        } else {
           this.syncElUpload()
          this.$message({ type: 'error', message: file.name + '上传失败!' })
        }
      this.isUploading = false
    },
    // 移除单张图片
    onRemoveHandler (index) {
      this.$confirm('确定删除该图片?', '提示', {
        confirmButtonText: '确定',
        cancelButtonText: '取消',
        type: 'warning'
      })
        .then(() => {
          this.imgList = this.imgList.filter((v, i) => {
            return i !== index
          })
        })
        .catch(() => {})
    },
    // 超限
    onExceed () {
      this.$refs.uploadRef.abort() // 取消剩余接口请求
      this.syncElUpload()
      this.$message({
        type: 'warning',
        message: `图片超限，最多可上传${this.limit}张图片`
      })
    },
    onDragStart (e) {
      e.target.classList.add('hideShadow')
    },
    onDragEnd (e) {
      e.target.classList.remove('hideShadow')
    }
  },
}
</script>
 
<style rel="stylesheet/scss" lang="scss" scoped>
/deep/ .el-upload {
  width: 100%;
  height: 100%;
}
 
// 上传按钮
.uploadIcon {
  width: 100%;
  height: 100%;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px dashed #c0ccda;
  background-color: #fbfdff;
  border-radius: 6px;
  font-size: 20px;
  color: #999;
 
  .limitTxt,
  .uploading {
    position: absolute;
    bottom: 10%;
    left: 0;
    width: 100%;
    font-size: 14px;
    text-align: center;
  }
}
 
// 拖拽
.vue-draggable {
  display: flex;
  flex-wrap: wrap;
 
  .draggable-item {
    margin-right: 5px;
    margin-bottom: 5px;
    border: 1px solid #ddd;
    border-radius: 6px;
    position: relative;
    overflow: hidden;
 
    .el-image {
      width: 100%;
      height: 100%;
    }
    .showBottom {
      position: absolute;
      bottom: 0;
      height: 15px;
      width: 100%;
      line-height: 15px;
      font-size: 5px;
      color: #fff;
      background-color: rgba(0,0,0,.5);
      cursor: pointer;
      padding: 0 5px 0 5px;
    }
    .shadow {
      position: absolute;
      top: 0;
      right: 0;
      background-color: rgba(0,0,0,.5);
      opacity: 0;
      transition: opacity .3s;
      color: #fff;
      font-size: 20px;
      line-height: 20px;
      padding: 2px;
      cursor: pointer;
    }
    &:hover {
      .shadow {
        opacity: 1;
      }
    }
  }
  &.hideShadow {
    .shadow {
      display: none;
    }
  }
  &.single {
    overflow: hidden;
    position: relative;
 
    .draggable-item {
      position: absolute;
      left: 0;
      top: 0;
      z-index: 1;
    }
  }
  &.maxHidden {
    .uploadBox {
      display: none;
    }
  }
}
</style>
 
 

/**
 * 数字存储大小格式化
 * @param {number} num 存储大小 单位：Byte
 * @param {number} digits 保留几位小数
 * @return {string} 2MB
 */
function toStorage (num, digits) {
  digits = digits || 2
  if (num < 1024) {
    return num + 'B'
  }
  num = (num * 1000 / 1024)
  const si = [
    { value: 1E18, symbol: 'E' },
    { value: 1E15, symbol: 'P' },
    { value: 1E12, symbol: 'T' },
    { value: 1E9, symbol: 'G' },
    { value: 1E6, symbol: 'M' },
    { value: 1E3, symbol: 'K' }
  ]
  for (let i = 0; i < si.length; i++) {
    if (num >= si[i].value) {
      return (num / si[i].value).toFixed(digits).replace(/\.0+$|(\.[0-9]*[1-9])0+$/, '$1') +
        si[i].symbol + 'B'
    }
  }
}
 
/**
 * 图片大小校验
 * @param {file} file el-upload文件对象
 * @param {number} size 限制的文件大小(kb) 默认10M
 */
function validImgUpload (file, size) {
  size = +size || 10240
  const isSizeOut = file.size / 1024 > size
  if (isSizeOut) {
    Message.error('上传图片大小不能超过' + toStorage(size * 1024))
  }
  return !isSizeOut
}
 
/**
 * 创建唯一的字符串
 * @return {string} ojgdvbvaua40
 */
function createUniqueString () {
  const timestamp = +new Date() + ''
  const randomNum = parseInt((1 + Math.random()) * 65536) + ''
  return (+(randomNum + timestamp)).toString(32)
}
 
export default {
  toStorage,
  validImgUpload,
  createUniqueString,
}
 

<template>
    <div>
        <DraggableImgUpload v-model="formData.imgList" :url="url"/>
    </div>
</template>
 
 
import DraggableImgUpload from '@/components/DraggableImgUpload/index.vue'
  
export default {
  components: { DraggableImgUpload },
}