我有一个通过 javascript、css 和 html 制作的 windows8 应用程序，它显示一个 rss 提要。有时，加载此提要可能需要 2-10 秒，这对我来说不是问题，但对于需要该应用程序的人来说，他们想知道它正在加载而不是冻结。我有一个动画加载动画 (GIF)，但我不知道如何在 rss 加载它时显示它。有任何想法吗？谢谢你的时间。
这是主要的javascript，
(function () {
"use strict";
WinJS.Binding.optimizeBindingReferences = true;
var app = WinJS.Application;
var activation = Windows.ApplicationModel.Activation;
var articlesList;
app.onactivated = function (args) {
if (args.detail.kind === activation.ActivationKind.launch) {
if (args.detail.previousExecutionState !== activation.ApplicationExecutionState.terminated) {
// TODO: This application has been newly launched. Initialize
// your application here.
} else {
// TODO: This application has been reactivated from suspension.
// Restore application state here.
}
articlesList = new WinJS.Binding.List();
var publicMembers = { ItemList: articlesList };
WinJS.Namespace.define("C9Data", publicMembers);
args.setPromise(WinJS.UI.processAll().then(downloadC9BlogFeed));
}
};
function downloadC9BlogFeed() {
WinJS.xhr({ url: "http://channel9.msdn.com/coding4fun/articles/RSS" }).then(function (rss) { // this is where it is calling the RSS
var items = rss.responseXML.querySelectorAll("item");
for (var n = 0; n < items.length; n++) {
var article = {};
article.title = items[n].querySelector("title").textContent;
var thumbs = items[n].querySelectorAll("thumbnail");
if (thumbs.length > 1) {
article.thumbnail = thumbs[1].attributes.getNamedItem("url").textContent;
article.content = items[n].textContent;
articlesList.push(article);
}
}
});
}
app.oncheckpoint = function (args) {
// TODO: This application is about to be suspended. Save any state
// that needs to persist across suspensions here. You might use the
// WinJS.Application.sessionState object, which is automatically
// saved and restored across suspension. If you need to complete an
// asynchronous operation before your application is suspended, call
// args.setPromise().
};
app.start();
})();