<van-uploader
              accept="*"
              v-model="imgList"
              :after-read="afterRead"
              :before-read="beforeRead"
              preview-size='25vw'
              @click-preview="handleclicksc"
              :before-delete="afterDelete"
              :preview-full-image="false"
              :disabled="isUploading?true:false"
              />
<!--點擊圖片或視頻出現(xiàn)放大圖片或播放視頻的彈窗-->
    <van-overlay :show="show" @click="show = false">
      <div class="wrapper" >
        <div class="img-block">
          <img v-if="urlType==='image'"   :src="url">
          <video autoplay class="video" v-if="urlType==='video'" :src="url" controls></video>
        </div>
<!--給視頻添加關(guān)閉圖標(biāo)-->
          <img v-if="urlType==='video'"
            @click="show=false"
            class="video-delete"
            src="./close.png"
          />
        </div>
    </van-overlay>

data(){
    return {
        isUploading:false,
        allInfoList:[]，
        url：'',  //彈窗展示的圖片/視頻路徑
        urlType：'',  //彈窗展示的類型
    }
 },
  watch: {
  //監(jiān)聽allInfoList，根據(jù)allInfoList動態(tài)地修改文件列表
    'allInfoList' () {
      this.imgList = []
      for (let item of this.allInfoList) {
        let data = {
          type: item.type,
          name: item.originalName,
          url: item.type === 'video' ? 'https://replacement.png' : 'https://' + item.fileUri
        }
        this.imgList.push(data)
      }
    }
  },
methods:{
//限制上傳的內(nèi)容為視頻或圖片
    beforeRead (file) {
      if (!file.type.startsWith('image') && !file.type.startsWith('video')) {
        this.$toast('請上傳圖片或視頻')
        return false
      }
      return true
    },
    afterRead (file) {
      file.status = 'uploading'
      file.message = '上傳中...'
      //添加上傳狀態(tài)，避免用戶在上傳未完成時點擊提交按鈕
      this.isUploading = true
      fileApi
        .uploadFile(file.file)
        .then(res => {
          if (res.data.status === 'success') {
            let fileDTO = response.data.fileDTO
            //為返回的數(shù)據(jù)添加文件類型，后面依據(jù)此來判斷
            if (file.file.type.startsWith('video')) {
              fileDTO.type = 'video'
            }
            if (file.file.type.startsWith('image')) {
              fileDTO.type = 'image'
            }
            //將返回的所有數(shù)據(jù)都保存起來（文件地址，文件名等）
            this.allInfoList.push(fileDTO)
          } else {
          //上傳失敗要清空數(shù)組，不然失敗的文件依舊會展示
            this.handleDelete(file.file.name)
          }
          file.status = ''
          file.message = ''
          this.isUploading = false
        })
        .catch((error) => {
          console.log(error)
          this.handleDelete(file.file.name)
          file.status = ''
          file.message = ''
          this.isUploading = false
        })
    },
    //根據(jù)文件名來查找到文件列表中要刪除的文件
    handleDelete (name) {
      this.imgList.forEach((item, index) => {
        if (item.file.name === name) {
          this.imgList.splice(index, 1)
        }
      })
    },
    //手動點擊刪除，修改包含所有信息的文件列表，通過watch根據(jù)該列表動態(tài)修改圖片文件列表
    afterDelete (file) {
      let name = file.name
      this.allInfoList.forEach((item, index) => {
        if (item.originalName === name) {
          this.allInfoList.splice(index, 1)
        }
      })
      return true
    },
   }
   //取消掉組件自帶的點擊預(yù)覽功能，自己添加（系統(tǒng)自帶預(yù)覽點擊視頻時會先視頻的播放圖片）
   handleclicksc (file) {
      let name = file.name
      for (let item of this.allInfoList) {
        if (item.type === 'video' && item.originalName === name) {
          this.url = this.getUrl(item.fileUri)
          this.urlType = 'video'
          this.show = true
        }
        if (item.type === 'image' && item.originalName === name) {
          this.url = this.getUrl(item.fileUri)
          this.urlType = 'image'
          this.show = true
        }
      }
    },

  .wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
  }
  .img-block {
    position: relative;
    img{
      z-index: 99;
      max-width: 100%;
      height: auto;
      object-fit: cover;
    }
    video{
      width: 100%;
      max-height: 100vh;
    }
  }
  .video-delete{
    width: 45px;
    position: absolute;
    top: 60px;
    left: calc(100vw - 60px);
  }

  <van-uploader :after-read="afterRead"  :accept="'image/*'" v-model="fileList" multiple="false"
                               :max-count="4"
                />

return {
      // 圖片信息
      files: {
        name: "",
        type: ""
      }

    // 單圖片上傳圖片
    afterRead(file) {
      this.files.name = file.file.name // 獲取文件名
      this.files.type = file.file.type // 獲取類型
      this.imgPreview(file.file)
    },
// 如果是多圖片按照這種寫法即可，不過需要在上面將multiple設(shè)置為true
// afterRead(file,name) { 方法參數(shù)設(shè)置為多參數(shù)
//        if (file instanceof Array && file.length) { // 判斷是否是多圖上傳 多圖則循環(huán)添加進(jìn)去
//            file.forEach(item => {
//                    this.imgPreview(item.file)
//            })
//        } else {
//            this.imgPreview(file.file)
//        }
// },
   
    // 處理圖片
    imgPreview(file) {
      let self = this
      let Orientation
      //去獲取拍照時的信息，解決拍出來的照片旋轉(zhuǎn)問題   npm install exif-js --save   這里需要安裝一下包
      Exif.getData(file, function() {
        Orientation = Exif.getTag(this, 'Orientation')
      })
      // 看支持不支持FileReader
      if (!file || !window.FileReader) return
      if (/^image/.test(file.type)) {
        // 創(chuàng)建一個reader
        let reader = new FileReader()
        // 將圖片2將轉(zhuǎn)成 base64 格式
        reader.readAsDataURL(file)
        // 讀取成功后的回調(diào)
        reader.onloadend = function() {
          let result = this.result
          let img = new Image()
          img.src = result
          //判斷圖片是否大于500K,是就直接上傳，反之壓縮圖片
          if (this.result.length <= 500 * 1024) {
            // 上傳圖片
            self.postImg(this.result)
          } else {
            img.onload = function() {
              let data = self.compress(img, Orientation)
              // 上傳圖片
              self.postImg(data)
            }
          }
        }
      }
    },
    // 壓縮圖片
    compress(img, Orientation) {
      let canvas = document.createElement('canvas')
      let ctx = canvas.getContext('2d')
      //瓦片canvas
      let tCanvas = document.createElement('canvas')
      let tctx = tCanvas.getContext('2d')
      // let initSize = img.src.length;
      let width = img.width
      let height = img.height
      //如果圖片大于四百萬像素，計算壓縮比并將大小壓至400萬以下
      let ratio
      if ((ratio = (width * height) / 4000000) > 1) {
        // console.log("大于400萬像素");
        ratio = Math.sqrt(ratio)
        width /= ratio
        height /= ratio
      } else {
        ratio = 1
      }
      canvas.width = width
      canvas.height = height
      //    鋪底色
      ctx.fillStyle = '#fff'
      ctx.fillRect(0, 0, canvas.width, canvas.height)
      //如果圖片像素大于100萬則使用瓦片繪制
      let count
      if ((count = (width * height) / 1000000) > 1) {
        // console.log("超過100W像素");
        count = ~~(Math.sqrt(count) + 1) //計算要分成多少塊瓦片
        //      計算每塊瓦片的寬和高
        let nw = ~~(width / count)
        let nh = ~~(height / count)
        tCanvas.width = nw
        tCanvas.height = nh
        for (let i = 0; i < count; i++) {
          for (let j = 0; j < count; j++) {
            tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh)
            ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh)
          }
        }
      } else {
        ctx.drawImage(img, 0, 0, width, height)
      }
      //修復(fù)ios上傳圖片的時候 被旋轉(zhuǎn)的問題
      if (Orientation != '' && Orientation != 1) {
        switch (Orientation) {
          case 6: //需要順時針（向左）90度旋轉(zhuǎn)
            this.rotateImg(img, 'left', canvas)
            break
          case 8: //需要逆時針（向右）90度旋轉(zhuǎn)
            this.rotateImg(img, 'right', canvas)
            break
          case 3: //需要180度旋轉(zhuǎn)
            this.rotateImg(img, 'right', canvas) //轉(zhuǎn)兩次
            this.rotateImg(img, 'right', canvas)
            break
        }
      }
      //進(jìn)行最小壓縮
      let ndata = canvas.toDataURL('image/jpeg', 0.2)
      tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0
      console.log(ndata)
      return ndata
    },
    // 旋轉(zhuǎn)圖片
    rotateImg(img, direction, canvas) {
      //最小與最大旋轉(zhuǎn)方向，圖片旋轉(zhuǎn)4次后回到原方向
      const min_step = 0
      const max_step = 3
      if (img == null) return
      //img的高度和寬度不能在img元素隱藏后獲取，否則會出錯
      let height = img.height
      let width = img.width
      let step = 2
      if (step == null) {
        step = min_step
      }
      if (direction == 'right') {
        step++
        //旋轉(zhuǎn)到原位置，即超過最大值
        step > max_step && (step = min_step)
      } else {
        step--
        step < min_step && (step = max_step)
      }
      //旋轉(zhuǎn)角度以弧度值為參數(shù)
      let degree = (step * 90 * Math.PI) / 180
      let ctx = canvas.getContext('2d')
      switch (step) {
        case 0:
          canvas.width = width
          canvas.height = height
          ctx.drawImage(img, 0, 0)
          break
        case 1:
          canvas.width = height
          canvas.height = width
          ctx.rotate(degree)
          ctx.drawImage(img, 0, -height)
          break
        case 2:
          canvas.width = width
          canvas.height = height
          ctx.rotate(degree)
          ctx.drawImage(img, -width, -height)
          break
        case 3:
          canvas.width = height
          canvas.height = width
          ctx.rotate(degree)
          ctx.drawImage(img, -width, 0)
          break
      }
    },
    //將base64轉(zhuǎn)換為文件
    dataURLtoFile(dataurl) {
      var arr = dataurl.split(','),
        bstr = atob(arr[1]),
        n = bstr.length,
        u8arr = new Uint8Array(n)
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n)
      }
      return new File([u8arr], this.files.name, {
        type: this.files.type
      })
    },
    // 提交圖片到后端
    postImg(base64) {
      let file = this.dataURLtoFile(base64)
      // 然后壓縮后的圖片放入集合，根據(jù)自己業(yè)務(wù)調(diào)用然后一起上傳
      this.fileCompressList.push(file)
    },