Android, YUI, Moodle

Question

The problem I'm having is the following:

I have an app with two separate modes: A WebView for browsing and a custom Canvas. The custom Canvas captures handwriting samples for language placement exams. Here's how it works. A user logs in to Moodle via the WebView. After they log in, they navigate to a Quiz inside Moodle. They click a link on one of the Quiz's questions and this launches an Intent which hides the WebView and shows the Canvas. The user then writes (using a stylus) on the Canvas. When a user is finished writing their essay (or whatever), they press a button that uploads an image file to Moodle. I am able to upload images to a point, it's getting them to show up in the HTML page that the user clicked the link in originally (see above) and to get Moodle to commit them to permanent storage that is the problem. Normally this is all accomplished through AJAX (really AJAJ since it's JavaScript and JSON) and when the user drops a file on this one component, the component refreshes and uploads the file.

Here is the problem: I need the WebView so that students can log in to Moodle through Shibboleth. But because the underlying JavaScript in the browser makes AJAX calls to the Moodle server and since the Java side of Android doesn't have access to the DOM, I have use the Apache HTTP components library to make some of the connections below basically to preserve the state of the HTML page in WebView.

In a desktop browser on, say, Windows, I use WebScarab to monitor the browser's requests and this is what I see: the browser uploads a file to Moodle via five successive calls to the following scripts:

1. POST https://[moodle website]/repository/repository_ajax.php [posts multipart form data]
2. POST https://[moodle website]/repository/draftfiles_ajax.php [posts some params]
3. GET https://[moodle website]/draftfile.php/[some_id]/user/draft/[some_id]/[somefilename.png] [returns an icon of the image for a filepicker from YUI]
4. POST https://[moodle website]/mod/quiz/processattempt.php [returns HTML page]
5. GET https://[moodle website]/mod/quiz/summary.php [returns HTML page]

Some of these scripts return, as you'd expect, JSON data since they're AJAX and not HTML. The final two calls (4 & 5) return HTML. Now, I can make all of those calls in succession in either the WebView or the Apache HTTP library, but if I do so with WebView, only JSON data is returned to the WebView in calls 1-3 (WebView treats the JSON data as a page and displays it wiping out whatever HTML page was displayed in it). If I capture and process the JSON data using the Apache HTTP library in Java, then the JavaScript components internal to the page do not get updated. If I split the calls so that I send only calls 4 & 5 to the WebView, the HTML merely returns WebView to the first question of the exam and Moodle acts as if I haven't uploaded anything.

I can verify that files are uploading if I manually refresh (press a link) the JavaScript UI elements in the page. I can't expect students to do this, though, because the link to do so is very tiny and it's not obvious that it does a refresh. I need a way to programmatically refresh this one element (it's part of YUI) or to get Android and the Java side to play more nicely with the JavaScript/DOM side.

My question is: does anyone know a way to 1) fire off a drag and drop event using YUI to an element inside an HTML page or 2) a way to consume the JSON data and pass it to an element inside the HTML page.

I'm banging my head against a wall trying to figure this out.

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OK, so I figured out that: javascript:document.getElementsByClassName(\"[name of link here]\")[0].click() works in Chrome on the desktop but doesn't work if I pass it to WebView.loadURL(). I just need to be able to simulate that click event reliably in WebView. It appears not to support click(). Anyone have any ideas?

Answer 1

The winning code is:

el = document.getElementsByClassName("[some element]")[0];
var event = document.createEvent("MouseEvents");
event.initEvent("click", true, true);
el.dispatchEvent(event);

This selects the link at [some element] and thereby fires an AJAX request that refreshes the FilePicker. For those working with Moodle, I had to add the above code to the same quiz question that handles so it is invoked by putting that code in its own function and calling it with WebView.loadURL("javascript:myRefreshFunction()").