You might want to be able to change the values of project properties or parameters when you initiate a build or activate a device without having to manually edit your project’s _defaults_.xml file, target device files, or resource handler code. You can achieve this by creating a custom panel (JPanel) for your project. For more information about project properties and parameters, see Setting Properties and Parameters for a Mobile Application Project.

Mobile Designer includes your custom JPanel into its Multi Build and Activate Handset dialogs. When you use the +Multi-Build Ant target to start a build, the Multi Build dialog includes your custom JPanel on the right. Similarly, when you use the ++Activate-Handset Ant target to activate a device, the Activate Handset dialog includes your custom JPanel. If you create a custom JPanel for a project, Mobile Designer incorporates the JPanel into both dialogs.

To use a custom JPanel, first you must code the JPanel. For more information, see Coding Your Custom JPanel.

After you code the JPanel, you set properties in your project’s build.xml file to indicate that you are using a JPanel and provide information about the location of the code. The JPanel properties must go in the build.xml file rather than the _defaults_.xml file because Mobile Designer must use the properties at the beginning of the build process before it reads the project properties in the _default_.xml and target device files. For information about the JPanel properties you need to set, see Setting JPanel Properties.