​wx.openDocument() 打不开pdf文档，文件下载好了没反应?

wx.downloadFile({

url: ‘https://www.xxxx.com/api/wechat/nfiles/download?fileid=1&userid=1’, //仅为示例，并非真实的资源

success: function (res) {

        // this.setData({

        //   files: res.tempFilePath

        // })

        wx.openDocument({

            filePath: res.tempFilePath,

            success: function (res) {

            console.log(‘打开文档成功’)

    }

})

}

文件下载好了没反应，提示unable to find app to open this type of document