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Tutorial

Using a Shared Library

Tutorial by Robert Hanson

The more you code, the more you find that you are able to reuse some of what you have already written. In this tutorial I want to show you the absolute easiest way to accomplish this, and point you to the Penlets.com Tools Library.

The General How-To

The current iteration of the PDK will compile your source code, create a jar from the compiled classes, and upload the finished jar to the pen. In my experimentation the easiest way to introduce an external source of classes is to tweak the source path in the build.xml of your project.

Below is the build.xml from the U.S. Capitals Trivia game.

<project name="US Capital Trivia" basedir="." default="dist">
    <property name="PENLETSDK_HOME" 
        location="C:\Prerelease_Livescribe_Penlet_SDK\0.6\penletsdk"/>
    <property name="common.builddir" value="/build" />
    <property name="java.src.dir" value="src/java"/>
    <import file="/build-common.xml" optional="false" />
</project>

With the exception of the project name and path to the PDK, it should look exactly like the one you use on every penlet project. Now the question is, what is the absolute easiest way to introduce an addition aource path?

Simply add one or more additional source paths to the java.src.dir property, separated by semi-colons.

<property name="java.src.dir"
    value="src/java;../penlets-tools-lib/src/java"/>

You can use relative or absolute paths. In this case I used a relative path that points up one directory to my Penlets.com Tools Library.

Setting up your IDE

Begin by creating a new project in your IDE, just like any other penlet project. If you are unsure how to do this, take a look at our tutorial on Developing Penlets in Eclipse or read the developer documentation that ships with the PDK.

Once you have your shared project you need to add a reference to it from the penlet project that will use the shared library.

In Eclipse you right-click on your penlet project, select Build Path, then Configure Build Path. Then on the Projects tab you add your shared library project.

In NetBeans you can add the shared source by right-clicking your project, select Properties, and add the source folder to the Java Sources Classpath property page.

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