Strange Java Issue

Update

See below for the solution. Spoiler – It’s a typo.

Back in April 2020, I wrote a little program to run a sequence of LibreOffice Impress Slide shows. For ease of deployment on Windows and Linux, I built the program in Java. And it worked just fine. Here’s what the program looks like:

You can follow the whole Saga of its development using this link. The program has been working very well on Linux Mint 19 and 20 and Windows 10 for a couple of months now. I’ve not changed anything since May 16. Here’s the github repository.

Continue reading “Strange Java Issue”

ImpressShowRunner Resizable

Update: All is working now. Get the latest jar file here. And the sources here.

Well that wasn’t that hard. After looking at this page on Java layout managers [TLDR], and then this page on Group Layout again [TLDR]. I just jumped in and tried it out. And whadda you know. It’s not that bad. It’s a little glitchy. Not as smooth as the Qt Layout manager, but it works. Here’s what is working so far.

So the list and path strings resize. And this uses 14 pt type rather than 16 pt, so it’s a little more compact and probably won’t mess up on some screens like the larger font size did.

Continue reading “ImpressShowRunner Resizable”

ImpressShowRunner Released

ImpressShowRunner is running well on both Windows 10 and Linux Mint 19.

Go here to get the Jar file.

Here is a complete description of the program and how to use it.

The program is distributed as a JAR file and requires Java SE 11 or later to run. OpenJDK 11 is built in to Linux Mint 19 and the normal windows SE release is currently Java 8.  This will not work to run the program since it was developed for the JDK 11 version of Java. Actually. Let me get back to you on that. I have JDK 14 installed on the system I use to test on Windows 10. I need to sort out these Java version numbers and confirm that the program works on Java 8. Are Java JDK versions different from the RunTime environment versions? Let’s see.

Continue reading “ImpressShowRunner Released”

Java – We have the Technology

ShowRunnerOnLinux_2020-04-20 13-36-24
Java App running on Linux

We recently proved that Java desktop programs can be easily deployed to Windows and Linux. Now we have proved that other complex parts of the program to run a series of Impress Shows in a loop.

  1. Running the command line to launch the Impress program to show the slide show.
  2. Finding out when the show is complete.
  3. Clicking the mouse repeatedly so that the show ends when it finally reaches the black screen.

1 and 2 are pretty easy. In Qt there is a class that executes a command in another process. And you can wait on it or check to see if it is complete. We can’t wait of course since Impress just waits forever for a click on a black screen at the end. Soooo.

3 is not so easy on Qt. The solution differs by OS. On windows you need to call the Kernel to send events to be dispatched through the event handler. UINPUT calls. On Linux, the easiest solution I found was to launch the “xtodo click 1” command to perform a mouse click. The xtodo command is easily installed on Linux, but this is another step to make the program work. But the Java solution is much easier.

Continue reading “Java – We have the Technology”

Java Deployment Is Easy

ShowRunnerOnLinux_2020-04-20 13-36-24.png
Show Runner on Linux

I’ve been using QtCreator and the QtFramework for many years to build apps for Windows / Linux. Deployment is always a struggle with the Qt Framework. Deployment is hard work. Lots of hand work and testing to make sure the installers are correct.

I’m now forever done with Qt for that. Java is sooooooo much easier to deploy.

The above shot is of the prototype Java Impress Show Runner app running on Linux from a JAR file built on Windows 10. It runs on Windows 10 and it runs on Linux, with no changes and instantly. No fiddling required.

Here’s what it takes to build apps this way. Just an overview, not the entire story, but it has only been Five days since I started with Eclipse and Java. So it’s not that big an effort.

Continue reading “Java Deployment Is Easy”