微信小程序实现打开并下载服务器上面的pdf文件

//查看并下载
See_download() {
   wx.downloadFile({//下载
    url: url,//服务器上的pdf地址
    filePath: wx.env.USER_DATA_PATH + '/test.pdf',//自定义文件地址
    suess: function (res) {
     var filePath = res.filePath
     wx.openDocument({//打开
      filePath: filePath,
      suess: function (res) {}
     })
    }
   })
}

<button type="primary" size="mini" open-type="share" > 转发 </button>

onShareAppMessage: function (res) {
  return {
   title: '转发的标题',
   path: '/pages/pdf/pdf?url=' + this.data.url,//这个url是要带到转发的那个页面的
   imageUrl: '/static/images/pdf.png', //图片可以是本地图片
  }
},

<view>
 <view class="btn_box" wx:if="{{show_btn}}">
  <button type="primary" bindtap="home">返回首页</button>
  <navigator class="back" open-type="exit" target="miniProgram">关闭小程序</navigator>
 </view>
</view>
  
/ pages/pdf/pdf.wxss /
.btn_box{
 width: 100%;
 box-sizing: border-box;
 padding: 30rpx 5%;
 position: absolute;
 : 50%;
 left: 50%;
 transform: translate(-50%,-50%);
 margin-: -50rpx;
}
button{
 margin-: 50rpx;
 height: 100rpx;
 line-height: 100rpx;
}
.back{
 width: 100%;
 margin-: 50rpx;
 height: 100rpx;
 line-height: 100rpx;
 color: #FFF;
 background-color: #E64340;
 box-sizing: border-box;
 font-size: 18px;
 text-align: center;
 border-radius: 10rpx;
}
// pages/pdf/pdf.js
Page({
 /
   页面的初始数据
  /
 data: {
  check:0,
  url:'',
  show_btn:false,
 },
 /
   生命周期函数--监听页面加载
  /
 onLoad: function (options) {
  this.setData({
   url: options.url
  })
 },
 // 返回首页
 home(){
  wx.reLaunch({
   url: '/pages/index/index'
  })
 },
 /
   生命周期函数--监听页面显示
  /
 onShow: function () {
  var that = this
  wx.showLoading({
   title: '加载中...',
  })
  if(this.data.check == 0){
   this.setData({
    check:1
   })
   wx.downloadFile({
    url: that.data.url,
    filePath: wx.env.USER_DATA_PATH + '/' + that.data.name,
    suess: function (res) {
     var filePath = res.filePath
     wx.openDocument({
      filePath: filePath,
      suess: function (res) {
       wx.hideLoading();
      }
     })
    }
   })
  }else{
   wx.hideLoading();
   this.setData({
    show_btn:true
   })
  }
 }, 
})