下载图片到本地

downloadImg() {
      const that = this;
      wx.showLoading();
      wx.downloadFile({
        url:
          'https://sc2.hexiaoxiang.com/imgo/poster/draw/ced68b61-7e20-4b3b-9796-01228b3acc43.jpg', //图片地址
        success: function (res) {
          //图片保存到本地
          wx.saveImageToPhotosAlbum({
            filePath: res.tempFilePath,
            success: function (data) {
              wx.hideLoading();
              that.showToast = true;
            },
            fail: function (err) {
              if (
                err.errMsg === 'saveImageToPhotosAlbum:fail:auth denied' ||
                err.errMsg === 'saveImageToPhotosAlbum:fail auth deny' ||
                err.errMsg === 'saveImageToPhotosAlbum:fail authorize no response'
              ) {
                // 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();
            }
          });
        }
      });
    }