<mp-uploader 
  files="{{files}}"  
  max-count="{{maximgs}}" 
  max-size="{{10 * 1024 * 1024}}" 
  title="图片上传" 
  tips="最多上传三张图片"
  size-type="{{sizeType}}" 
  sourceType="{{sourceType}}" 
  delete="{{true}}" 
  select="{{selectFile}}" 
  upload="{{uplaodFile}}"
  binddelete="delimg"
  bindfail="uploadError" 
  bindsuccess="uploadSuccess" 
></mp-uploader>

{
  "usingComponents": {
    "mp-toptips": "weui-miniprogram/toptips/toptips",
    "mp-form": "weui-miniprogram/form/form",
    "mp-uploader": "weui-miniprogram/uploader/uploader",
    "mp-checkbox": "weui-miniprogram/checkbox/checkbox",
    "mp-checkbox-group": "weui-miniprogram/checkbox-group/checkbox-group",
    "mp-cells": "weui-miniprogram/cells/cells",
    "mp-cell": "weui-miniprogram/cell/cell"
  }
}

// pages/default/default.js
const app = getApp()
Page({
  data: {
    //mp-uploader
    maximgs:5,//最大上传数
    files: [],  //上传组件绑定的文件urls
    sizeType: ['compressed'], //压缩上传,可以是['original', 'compressed']
    sourceType: ['album', 'camera'], //相册,或拍照
  },
  onLoad: function (options) {
    this.setData({
      //通过bind(this)将函数绑定到this上,以后函数内的this就是指全局页面
      //setdata以后,这两个函数就可以传递给mp-uploader了
      selectFile: this.selectFile.bind(this),  
      uplaodFile: this.uplaodFile.bind(this)
    })
  }, 
  //mpuploader选择图片时的过滤函数，返回true表示图片有效
  selectFile(files) {
    wx.showLoading({ title: '', })
    // 如果有大文件可以压缩一下
    // 返回false可以阻止本次文件上传
  },
  uplaodFile(files) {   
    // 图片上传的函数，必须返回Promise
    //Promise的callback里面必须resolve({urls})表示成功，否则表示失败
    return new Promise((resolve, reject) => {         
      const tempFilePaths = files.tempFilePaths;
      const that = this;
      let finished = {url:[]}  //本次上次成功的URL存入这个变量,被success方法的e.detail承接
      for (var i = 0; i < tempFilePaths.length; i++) {
        let filePath = tempFilePaths[i]  //原名
        let cloudPath = 'qyzj' + new Date().getTime() + '-' + i + filePath.match(/\.[^.]+?$/)[0]  //云存储文件名
        wx.cloud.uploadFile({
          filePath, cloudPath,
          //成功
          success: function (res) {
            if (res.statusCode != 200 && res.statusCode != 204 && res.statusCode != 205) reject('error')// 可能会有好几个200+的返回码，表示成功
            finished.url.push({url:res.fileID})     //成功一个存一个到本次上传成功列表
            //如果本次上传的文件都完成 或全局已经存满3张,resolve退出
            if (finished.urls.length === tempFilePaths.length || that.data.files.length +finished.urls.length == this.data.maximgs)
            resolve(finished)
          },
          //失败
          fail: function (err) { console.log(err) }
        })
      }
    })
  },
  uploadError(e) {
    console.log('upload error', e.detail)
    wx.hideLoading()
    this.setData({ error: "上传失败,可能有些照片过大" })
  },
  uploadSuccess(e) {
    console.log('upload success', e.detail)
    this.data.files=this.data.files.concat(e.detail.url)
    this.setData({files:this.data.files})
    wx.hideLoading()
  },
  //删除图片 detail为{index, item}，index表示删除的图片的下标，item为图片对象。
  delimg(e) {
    this.data.files.splice(this.data.files.findIndex(item => item == e.detail.item), 1)
  } 
})