小程序保存图片到相册

开发过程中需要保存到相册，可以使用这个方法，要注意的是需要配置downloadFile合法域名

实例

 // 保存到相册
 savePoster() {
  let that = this
  wx.getSetting({
    success(res) {
      if (res.authSetting['scope.writePhotosAlbum']) {
        that.saveImg();
      } else if (res.authSetting['scope.writePhotosAlbum'] === undefined) {
        wx.authorize({
          scope: 'scope.writePhotosAlbum',
          success() {
            that.saveImg();
          },
          fail() {
            that.authConfirm()
          }
        })
      } else {
        that.authConfirm()
      }
    }
  })
},
// 授权拒绝后，再次授权提示弹窗
authConfirm() {
  let that = this
  wx.showModal({
    content: '检测到您没打开保存图片权限，是否去设置打开？',
    confirmText: "确认",
    cancelText: "取消",
    success: function (res) {
      if (res.confirm) {
        wx.openSetting({
          success(res) {
            if (res.authSetting['scope.writePhotosAlbum']) {
              that.saveImg();
            } else {
              wx.showToast({
                title: '您没有授权，无法保存到相册',
                icon: 'none'
              })
            }
          }
        })
      } else {
        wx.showToast({
          title: '您没有授权，无法保存到相册',
          icon: 'none'
        })
      }
    }
  });
},
//保存图片
saveImg: function () {
  var that = this;
  var imgUrl = that.data.imgurl; //需要保存的图片地址
  console.log(imgUrl)
  wx.downloadFile({
    url: imgUrl,
    success(res) {
      // 只要服务器有响应数据，就会把响应内容写入文件并进入 success 回调，业务需要自行判断是否下载到了想要的内容
      console.log('downloadFileres', res);
      wx.saveImageToPhotosAlbum({
        filePath: res.tempFilePath,
        success(res) {
          console.log("保存图片：success");
          wx.showToast({
            title: '保存成功',
          });
        },
        fail: res => {
          console.log(res);
          wx.showToast({
            title: '保存失败',
          });
        }
      })
    }
  })
},