Monthly Archives: November 2006

Within Swing you’re supposed to be able to specify the minimum size for a frame with a simple call. For instance, assume that I made a frame that extends JFrame. Consider adding the following line to the constructor:

setMinimumSize(new Dimension(600,400));

This specifies that the frame should never shrink below 600 by 400 pixels in size. Great, huh? The problem is it doesn’t work:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4320050

And it hasn’t worked since Java 1.2. And the only reason I don’t think it was a problem prior to that is that it wasn’t part of JDK 1.1 or 1.0. However there is a way to get around it; overriding the paint() method.

The paint() method is part of the java.awt.Container package. And it’s called when a container needs to be repainted. We just need to override that event, and stop the event when the minimum width and height that are specified are reached. If and the repaint needs to occur you need to call the repaint() methods for any containers within the frame (such as JPanels, etc). I’ve adopted the code that’s in the bug report I mentioned above. Try it in your own GUI apps.

Fortunately this won’t be an issue too much longer – this bug was finally fixed in Java 6, due out Real Soon Now ™.

        public void paint(Graphics g) {
               double w = getSize().getWidth();
               double h = getSize().getHeight();

               if (w < 600 && h < 400) {
                       setVisible(false);
                       setSize(600, 400);
                       setVisible(true);
                       return;
               } else if (w < 600) {
                       setVisible(false);
                       setSize(600, (int) h);
                       setVisible(true);
                       return;
               } else if (h < 400) {
                       setVisible(false);
                       setSize((int) w, 400);
                       setVisible(true);
                       return;
               }

               jPanel1.repaint(); // Components are on this panel
               statusBar.repaint(); //I also have a JXStatusBar

               if (!firsttime) // Set to 'true' in frame constructor
               {
                       jPanel1.validate();
               } // so that validate() isnt called
               else // immediately on frame.show()
               {
                       firsttime = false;
               }
       }

[Originally Posted 25-Dec-2005]

I ran across this tidbit from the Eclipse Developer Journal’s website. It took a bit of digging so I thought I’d share here for posterity and whomever might read. Apparently it is possible to move an Eclipse project out to ANT and vice-versa. Note that this only works in Eclipse 3.1

To export your project settings to an ANT build file:

1. In your navigator window, look for a file called “.project”
2. Right click on the file and click on “export”
3. On the window that pops up, select “Ant Buildfiles” and click on “next”
4. Select the appropriate project to use to generate the ANT buildfile
5. Click “finish”

You should now have two new build files on your project, “build.xml” and build-user.xml.

Any custom targets you create should go on build-user.xml, since build.xml will be overwritten every time a build file is generated.

To create a project from an existing ANT buildfile:

1. Click on File->New->Project
2. Select “Java Project from existing Ant Buildfile” and click “next”
3. Enter a project name, and select the build file to use to create the project
4. Select the javac declaration to be used to define the project
5. Click finish

Thanks to the author of the original article (http://eclipse.sys-con.com/read/100814.htm)

[Originally Posted 18-Nov-2005]

Here’s a pretty cool trick for Java GUI-app developers. From the O’Reilly Book “Swing Hacks”, Joshua Marinacci and Chris Adamson show how to make transparent windows…

http://www.onjava.com/pub/a/onjava/excerpt/swinghks_hack41/

[Originally Posted 30-Oct-2005]

I’m not using Borland Together Eclipse Edition version 7 right now so I decided to un-install it. Upon running the uninstall program for Together EC, I got this rather useless error from the uninstall program:

Windows error 3 occurred while loading the Java VM.

It turns out that the reason is because after installing Together I had installed JDK 5. The older uninstall and the newer JDK don’t play nice together. But I found a fix – of all places on the HP Dev Resource Central forum.

At a command prompt run the following and you should be fine:

C:> “C:BorlandTogetherECUninstallerDatauninstall.exe” LAX_VM “C:jdk1.5.0_03binjava.exe”

Use whatever path you have your JDK 5 installation set for and you should be able to uninstall without an issue.