Programming PocketPC PDA

Java Programming for IPAQ 4350

The following are step-by-step instructions on how to get java and PlaceLab working on the PDAs we're using this quarter. I would suggest using ActiveSync 3.8 (or something comparable) to be able to transfer files to the PDA and navigate the folders on the PDA more easily.

Installing PlaceLab and J9 VM

The PlaceLab v2.0 install includes the J9 java run-time environment, the PlaceLab source code, pre-compiled jar files, platform-specific executables, and scripts.

The default version of the PlaceLab toolkit has some issues with detecting the network cards used in the iPaq 4350, so I have uploaded a slightly modified install for the class. Download the modified version of PlaceLab toolkit from here: placelab.zip. For anyone interested, the specific modifications were:

Some non-critical files and directories (like /doc, /placelabdata) are removed to ensure that the install will fit in the PDA memory.
The spotter-ce.dll is modified to enable PlaceLab to recognize the iPaq network card used in the 4350 (among others). (Details about the tweaks required to the default spotter.dll are available here and here).

Unzip the file, and use ActiveSync to copy the "placelab" folder onto the root directory ("/") of your PDA - this may take a few minutes. To do this, use the ActiveSync file explorer to drag the file to "My Pocket PC" - it should show up in the same directory as the "Windows" directory.

You can use the file explorer on the PDA to go to execute the programs (.lnk files) in PlaceLab/run/ and ensure that the install is working correctly. The stumbler program (MyDevice->placelab->run->stumbler) should be able to detect networks.

Compiling Java scripts and creating .lnk files to run them

To run your own programs on the PDA, you will need to execute the following steps. Some sample java files to test with are helloworld.java and javatest.java. (Javatest is basically the WiFiSpotterExpample outside of any package.)

Compile your .java file to generate a .class file: I would suggest using the J9 JVM available with placelab, but have also tested a simple application compiled using the Sun Java JDK (1.4.2). For J9, you can use the J9 install available with the toolkits on the PlaceLab downloads page.
After installing the toolkit on the development machine, you can compile your program under cygwin using a command line like:
```
c:/placelab-win32/j9/bin/j9c.exe -classpath c:/placelab-win32/j9/lib/classes.zip\;c:/placelab-win32/src helloworld.java
```
(from windows using cygwin, with placelab-win32 unzipped in c:/placelab-win32. Helloworld does not require c:/placelab-win32/src in the classpath, but javatest or any other application using PlaceLab will.)
Or, from DOS command prompt, it will look like:
```
c:\placelab-win32\j9\bin\j9c.exe -classpath c:\placelab-win32\j9\lib\classes.zip;c:\placelab-win32\src helloworld.java
```
(';' is enough as separator, you don't need '\')
Copy the .class to your PDA (e.g. copy helloworld.class or javatest.class. to a directory on the PDA called /test)
Create a .lnk shortcut for your program, and copy it to the same folder on your PDA:
For example, for the above setup, javatest.lnk would contain (on a single line):
```
234#\placelab\j9\bin\j9.exe
"-Xbootclasspath:\placelab\j9\lib\classes.zip;\placelab\lib\ppro-ui-win.zip"
-Dplacelab.ini=/placelab/placelabdata/placelab.ini -cp
"/placelab/lib/placelab.jar;/test" javatest
```
- The number "234#" is supposed to represent how many chars are in the link, but does not seem to be used.
- "\placelab\j9\bin\j9.exe" is the path to the VM
- The next two items point to PlaceLab specific libraries, etc.
- "-cp" is the class path (include any external jars you need as well as your application directory or jar). In this case, javatest.class is in the folder /test. The placelab.jar file is included in the classpath, since javatest makes use of the PlaceLab libraries.
- The last item is the main class to run. In this case, it's javatest.
Run the program by clicking on the .lnk file on the PDA

Misc Tips

If you are having problems with programs complaining about insufficient memory, you should check the task manager (silver arrow button) and close excess applications.
Even if you don't plan to use PlaceLab functionality, you can use their applications as a starting point for the GUI or file organization of your program.