小程序二维码--保存图片

 // 保存海报
  postSave(e) {
    wx.showLoading({
      title: '保存中...'
    })
    wx.downloadFile({
      url: 'http://xxx.com/poster.png',
      success: function (res) {
        //图片保存到本地
        wx.saveImageToPhotosAlbum({
          filePath: res.tempFilePath,
          success: function (data) {
            wx.hideLoading()
            wx.showModal({
              title: '提示',
              content: '您的推广海报已存入手机相册，赶快分享给好友吧',
              showCancel:false,
            })
          },
          fail: function (err) {
            if (err.errMsg === "saveImageToPhotosAlbum:fail:auth denied" || err.errMsg === "saveImageToPhotosAlbum:fail auth deny") {
              // 这边微信做过调整，必须要在按钮中触发，因此需要在弹框回调中进行调用
              wx.showModal({
                title: '提示',
                content: '需要您授权保存相册',
                showCancel: false,
                success:modalSuccess=>{
                  wx.openSetting({
                    success(settingdata) {
                      console.log("settingdata", settingdata)
                      if (settingdata.authSetting['scope.writePhotosAlbum']) {
                        wx.showModal({
                          title: '提示',
                          content: '获取权限成功,再次点击图片即可保存',
                          showCancel: false,
                        })
                      } else {
                        wx.showModal({
                          title: '提示',
                          content: '获取权限失败，将无法保存到相册哦~',
                          showCancel: false,
                        })
                      }
                    },
                    fail(failData) {
                      console.log("failData",failData)
                    },
                    complete(finishData) {
                      console.log("finishData", finishData)
                    }
                  })
                }
              })
            }
          },
          complete(res) {
            wx.hideLoading()
          }
        })
      }
    })
  }