|«« Free Software Realities||Let's Talk About the "I" Word: Innovation »»|
I'm Ryan Lowe, a Software Engineering graduate living in Ottawa, Canada. I like agile software development and Ruby on Rails.
I write this blog in Canadian English and don't use a spell checker. Typos happen.
» Full-time Ruby on Rails freelancer
» Full-time with Rails since May 2005
» Former committer for RadRails (now Aptana)
» I also have a few Rails side-projects in development:
1. wheretogoinTO.com Toronto nightlife
2. Hey Heads Up! TODO list and sharing
3. Layered Genealogy family history research
4. foos for foosball scoring
5. fanconcert for music fans (on hold)
Hiring Rails developers? I can telecommute by the hour from Ottawa, Canada
»» Email: rails AT ryanlowe DOT ca
Now hosted on Hey! Heads Up -- check it out!
firstname.lastname@example.org no more
Forging Email Headers: Good, Bad or Ugly?
Sarcastic Dictionary (Part 1 of Many)
Twisting Rails is Risky Business
Risky Business? My Take on Early Alphas
Whoa, it's August 2007
A Postscript to "Growth at the grassroots"
An Abuse Trifecta
»» All Blog Posts
David Heinemeier Hansson
James Duncan Davidson
Signal vs. Noise
Amy Hoy: (24)slash7
Luis de la Rosa
Roll Your Own ApplicationWindow OnOpenListener
JFace's ApplicationWindow object doesn't seem to have a listener that is triggered when it is opened. This is unfortunate because there are lots of things that you might want to do when the "UI is ready", like load it with data.
Warning, the following explanation is from 30,000 feet ...
ApplicationWindow uses the method open() to show itself. Developers usually make this method call block, meaning that code after open() doesn't execute until after the window is closed. After open(), everything is event-driven. So you can't make a call to your database after open() and expect it to affect the GUI. There is a way to get around it though.
The windowing toolkit that JFace uses, SWT, is a layer on top of each operating system it is written to. SWT receives messages from the operating system and stuffs them into a queue. These are messages about if the mouse pointer moved, if a click happened or if a letter was typed. SWT then processes these events and updates the application's GUI.
Do you remember me blogging about asyncExec()? This method call just puts a Runnable on SWT's queue, usually from a non-UI thread because SWT only allows the SWT thread to modify it. But who says you can't use it from the UI thread too? Here's how I did it:
public static void main(String args)
Now the task runs right after the window appears. The trick is window.create(). Usually you don't have to call it but it will initialize the Shell for you (I found that out poking around in the SWT code). Otherwise the Shell is null until open() (too late!). Without window.create(), you can't getDisplay() from the window's Shell and you can't use asyncExec().
BTW, I used this technique to put progress bars in AudioMan when it loads and saves the repository on open and exit. It looks sweet! I'll be releasing a new version of AudioMan (0.3.1) shortly.Posted at March 01, 2004 at 07:34 AM EST
Last updated March 01, 2004 at 07:34 AM EST