In my last post, I alluded to the fact that you can lay out your visual elements and controls on your Android application screens (your Activity objects) using XML. In this post, I'm going to give you a peek at what that XML looks like.
Android applications can be constructed from four different types of components: activities, services, broadcast receivers, and content providers. Of the four, the only one that you must use at least one of in every application (and the only one that I've had to use so far) is the activity.
I'm not going to even try to give a full explanation of what an activity is: the Application Fundamentals page on the Android Developers site provides a thorough (and rather long) explanation of activies as well as the other three components. So I'm just going to give a bullet-list overview to give you a conceptual overview of what an activity is.
Two months ago, my boss asked me to try and build a native Android application based on the mobile website I had created for the university's annual Maryland Day festival. Both he and I are part of an IT initiative in our department tasked with figuring out how best to provide IT services to smartphone users on campus, and while we have in-house expertise in iPhone development, none of us were familiar with what would be involved in building Android applications. So he asked me to give it a shot.
The focus of the jQuery UI Meetup I attended last week was on jQuery UI 1.8 and to work out some questions regarding future meetups, but of course some other topics came up as well. One of those other topics was the not-uncommon problem of having certain HTML content, meant to be hidden or styled by jQuery, briefly appearing in its raw form before the page has fully loaded and jQuery gets to do its thing. Apparently the term for this phenomenon is "FOUC", which stands for "flash of unstyled content."
Now, if you took it as an absolute that any and all uses of your web page had Javascript enabled, you could solve a FOUC problem by assigning a CSS style to the problem content that hid the content right from the get-go, and then you could use Javascript to reveal the content at the appropriate time. But such a solution would fail if the user had Javascript disabled--the content would never be visible to them--and it's contrary to the idea of progressive enhancement (the idea that the page is usable as is, but is enhanced when Javascript is available).
So in answer to the question on FOUC, Richard Worth (the speaker for the meetup) pointed us to the following blog post by Karl Swedberg:
http://www.learningjquery.com/2008/10/1-way-to-avoid-the-flash-of-unstyled-content
The post provides a pretty good explantion of the technique (which is pretty simple), so I don't feel the need to explain it or add to it. Just thought I'd put it out there because it would be hard to find via a web search if you didn't know how to describe the problem and didn't know the FOUC acronym.
This past Wendsday, I attended the first jQuery UI meetup at the Microsoft office in downtown Washington D.C. The sole presenter for the meeting was Richard Worth, one of the members of the jQuery UI development team, who spoke to us about the new features in the latest release of jQuery UI, version 1.8...and mentioned a few things that were planned for the next release.
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