onLoad: function (options) { var lent = [ "https://wx.qlogo.cn/mmhead/XtxAEvJhLWZbe5xLnXFw1EjI54NkntBricIbfBkvNiajE/64", "https://wx.qlogo.cn/mmhead/XtxAEvJhLWZbe5xLnXFw1EjI54NkntBricIbfBkvNiajE/64", "https://wx.qlogo.cn/mmhead/XtxAEvJhLWZbe5xLnXFw1EjI54NkntBricIbfBkvNiajE/64"] var temp = [] for (var i = 0; i < lent.length; i++) { wx.downloadFile({ url: lent[i], success(res) { if (res.statusCode === 200) { temp[i] = res.tempFilePath } } }) } console.log(temp)} |
典型的闭包问题，可以通过立即函数或是forEach写箭头函数来解决。
for(vari = 0; i < lent.length; i++) {let index = i
wx.downloadFile({url: lent[index ],success(res) {if(res.statusCode === 200) {temp[index ] = res.tempFilePath}}})}显示出来，为啥
console.log(temp[0])
输出 undefined
异步的问题，你要写到temp[index] = res.tempFilePath 这一行后面console.log
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