我试图在javascript中创建一个对象数组,但是当我尝试将数组打印到控制台(使用chrome)时,我得到的都是undefine,除非我在推送后打印数组。
var subitems = [];
for (var i = 1; i < 1000; i = i + 50) {
$.getJSON('http://gdata.youtube.com/feeds/api/users/' + username + '/subscriptions?max-results=50&start-index=' + i + '&alt=json', function (data) {
var output = "";
for (var x in data.feed.entry) {
var subtitle = data.feed.entry[x].yt$username.$t;
var subchannel = data.feed.entry[x].yt$channelId.$t;
var subphoto = data.feed.entry[x].media$thumbnail.url;
subitems.push({
subtitle: subtitle,
subchannel: subchannel,
subphoto: subphoto
});
console.log(subitems[0]); //Prints Fine
output += '<div class="subtitle"><img src="' + subphoto + '"> <a href="http://www.youtube.com/channel/' + subchannel + '">' + propercase(subtitle) + '</a></div>';
}
maincontent.innerHTML = maincontent.innerHTML + output;
});
}
console.log(subitems[0]); //This is undefined
答案 0 :(得分:1)
以下是执行此操作的“更简单”方法:计算XHR请求并在所有请求都返回时触发done函数:
var xhrCount = 0;
for (var i = 1; i < 1000; i = i + 50) {
xhrCount++; // increment before request
$.getJSON('http://gdata.youtube.com/feeds/api/users/' + username + '/subscriptions?max-results=50&start-index=' + i + '&alt=json', function (data) {
// process response
// decrement after request is processed
xhrCount--;
if (xhrCount === 0) {
// at this point all requests have returned
console.log(subitems);
}
}
}
}
更新:更好的方法是使用jQuery.Deferred()
对象。一个quick demo is setup here,需要一些修复。一般的想法是跟踪您所做的所有AJAX请求,将它们传递给deferred.when()
并使用deferred.done()
分配完成功能。代码(为了便于阅读而修剪):
var subitems = [];
var deferreds = [];
for (var i = 1; i < 1000; i = i + 50) {
var deferred = $.getJSON('https://gdata.youtube.com/feeds/api/users/warnerbrospictures/uploads?max-results=50&start-index=' + i + '&alt=json', function (data) {
for (var j = 0; j < data.feed.entry.length; j++) {
subitems.push({
title: data.feed.entry[j].title.$t
});
}
});
deferreds.push(deferred);
}
$.when.apply($, deferreds).done(function () {
console.clear();
console.log(subitems);
for (var i = 0; i < subitems.length; i++) {
console.log(subitems[i].title);
}
});
注意:Google数据Feed包含结果总数,因此可以消除硬编码“1000”。
答案 1 :(得分:-2)
尝试将数组声明为:
var subitems = [{}];