uping:function(e){         var that=this;         wx.chooseMessageFile({   //从聊天获取文件，选择后存为临时文件 temp           count: 1,             success(res){                 console.log(res);                 var name="http://store/"+res.tempFiles[0].name;                 wx.saveFile({    //   临时文件转缓存文件    store                     tempFilePath:res.tempFiles[0].path,                     success(e){                         console.log(e);                         var f_manager =wx.getFileSystemManager();                         f_manager.rename({   //重命名                             oidPath:e.savedFilePath,                              newPath:name,                             success(){                                 console.log("改名成功，名为:",name)                             },                             fail(m){                                 console.log(m);                                 console.log(e.savedFilePath,name);                             }                         });                     that.update_filelist(that);                        }                 })             }         })     } 运行结果如图： [图片] 我将savefile的返回值赋给 rename函数的oldpath，运行后报 oldpath 未定义，但在log里能正确显示值 ：http：//store......... ,请问是为什么？