Cannot read property 'uid' of undefined;at weixinmao_house/pages/shoucang/index page lifeCycleMethod onLoad function TypeError: Cannot read property 'uid' of undefined at l.onLoad (https://weixinmao_house/pages/shoucang/index.js:18:28)at l.(https://lib/WASubContext.js:1:1437831)at l.__callPageLifeTime__ (https://lib/WASubContext.js:1:1437571)at Tt (https://lib/WASubContext.js:1:1457198)at At (https://lib/WASubContext.js:1:1458707)at Function.(https://lib/WASubContext.js:1:1464558)at i.(https://lib/WASubContext.js:1:1433421)at i.emit (https://lib/WASubContext.js:1:442742)at Object.emit (https://lib/WASubContext.js:1:430227)at https://lib/WASubContext.js:1:458653

这个是什么意思？请大神指导