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Developing Java ME Applications for Multiple Devices

This tutorial is the second in series designed to get developers started with MIDP and CDC development. It is strongly recommended that you complete the Java ME MIDP Quick Start Guide before beginning this tutorial. We continue building on the "MyHello" project completed in the MIDP Quick Start and show you how to deploy it to different emulators and customize the code for specific device environments. Note that the concepts and methods demonstrated in this tutorial can also be applied to CDC applications created in the IDE.

Content on this page applies to NetBeans IDE 6.0, 6.1 and 6.5

Required Software Adding Emulator Platforms Using Configurations Creating Abilities Adding Preprocessor Code for Specific Configurations Next Steps

Requirements

To complete this tutorial, you need the following software and resources:

Software or Resource Version Required

NetBeans IDE with Java ME Version 6.5 or
version 6.1

Java Development Kit (JDK) Version 6 or
version 5

Adding Emulator Platforms

Emulator platforms are provided by mobile phone manufacturers so that developers can simulate the behavior of specific mobile devices to help debug the applications they create. NetBeans IDE Mobility includes the Sun Java Wireless Toolkit, and supports many other software development kits (SDKs) that you can download from vendor sites such as Nokia, Sony Ericsson, and Motorola. You can check the NetBeans Mobility FAQ for a list of supported MIDP emulators that includes download links.

Adding a New Emulator Platform

Choose Tools > Java Platforms from the main toolbar. In the Java Platform Manager dialog, click the Add Platform button. In the Add Java Platform dialog, select the Java ME MIDP Platform Emulator. Click Next. In the Add Java Platform dialog, the IDE searches for all available Java ME platforms and lists them in the Platform Folders section. Platforms that are compliant with the Unified Emulator Interface (UEI) standard are verified and appear with a check in the checkbox next to the platform name. Platforms that are not UEI-compliant, or that require customization to install are listed in red. The wizard also identifies which platforms have already been installed.
NOTE: To install platforms that are not UEI-compliant, click the Back button and choose Custom Java Micro Edition Platform Emulator. In the Platform Folders section of the Add Java Platform dialog, check all of the platform emulators you want to install. After the platforms are detected, they are installed. Click Finish. Then click Close. To add a new emulator platform to a project Choose File > "MyHello" Properties. Choose the Platform node, then choose the name of the new emulator (for example, Sun Java Wireless Toolkit 2.5.2) from the Emulator Platform drop-down menu. Click OK.

Changing the Default Emulator Device

Right-click the MyHello Project node and choose Properties. In the Properties dialog, choose the Platform node. Here, you can change the device for the default configuration. Click the Device drop-down list and choose QwertyDevice. Click OK. Run the application again, and the application runs in the QwertyDevice emulator.

Using Configurations

You can use configurations to create more than one set of distribution JAR and Java Application Descriptor (JAD) files for your project. This enables you to create one set of source code and customize it for each mobile device you're programming for.

Adding a Configuration

Right-click the MyHello Project node and choose Properties. In the Properties dialog, Choose Add Configuration from the Project Configuration drop-down list. This opens the Add Configuration dialog. Enter a name for your configuration in the Configuration Name field. The name should identify the target platform you deploy the JAR/JAD created for this configuration. For this example, enter BlackWhiteDisplay and click OK. You have just created a new configuration. Configurations can also be added by clicking the Manage Configurations button in the Properties dialog. This brings up the Project Configuration Manager dialog which contains options for adding, removing, or duplicating configurations.

Changing the Project Configuration

You can create different types of project configurations using the templates in the New Project wizard. You can also use the drop-down Configuration menu in the main toolbar to quickly change project configurations.

Customizing a Configuration

You can add as many configurations as you would like to your project. You can then modify settings in the Project Properties dialog for each configuration that you've added.

Right-click the MyHello Project node and choose Properties. In the Properties dialog, choose the Platform node. Choose the BlackWhiteDisplay configuration from the configuration combo box at the top of the Properties dialog. The components in the Platform dialog are all disabled. This is because this configuration is currently taking the values used by the default configuration for this panel. Uncheck the Use Values from "DefaultConfiguration" option at the top of the panel. All components on this panel can now be edited. Change the Device option to DefaultGrayPhone. Toggle the Project Configuration dialog at the top of the Properties dialog and observe that the Device option changes based on which configuration is currently selected. This method of configuration customization works for each panel (other than the general panel) in the dialog. Click OK to save your configuration changes and exit the Properties dialog.

Creating an Ability

An Ability is a specific attribute of a project configuration. It can be a physical attribute such as screen size, or an API or JSR supported by the configuration. You can create a new ability and associate it with one or more project configurations. You can then use preprocessior code blocks to associate certain code with that ability. If you later need to add or remove configurations, you do not have to go through all your code and associate the configuration with each code block. Instead, you need only to add that ability to the configuration. The configuration is then automatically associated with any code block associated with that ability.

Right-click on the MyHello project node and choose Properties. Choose Abilities from the Category menu tree. Choose a configuration from the Project Configuration dropdown menu. This associates the ability with that configuration. If necessary, uncheck the Use Values from "DefaultConfiguration" checkbox. Click the Add button. This opens the Add Ability dialog.

In the Add Ability dialog, enter a name for the ability, or choose an ability from the drop-down menu. Optionally, enter a value for the ability. Click Ok to close the Add Ability dialog. The ability is now associated with the selected project configuration.

You can associate the ability with other configurations by choosing a different configuration from the Project Configuration menu and clicking the Add button.

Adding Preprocessor Code for Specific Configurations

Preprocessor blocks enable you to create, manage and track code that is specific to one or more project configurations or abilities. The code is enabled (or disabled) only for the configurations or abilities you identify.

In the HelloMIDlet.java Editor window, right-click on the source code line where TextBox is instantiated ( helloTextBox = new javax.microedition.lcdui.TextBox(null, "Make my day",120, 0x0);). Right-click on the line and choose Preprocessor Blocks > Create If/Else Block. In the first, pink section, append the word "Color" to the "Hello World" string. In the second, gray section, add "Gray" to the "Make my day " string. The code marked by the //#if preprocessor directive is in effect whenever the active configuration matches the directive value (in this case, DefaultConfiguration.) The code encased by the //#else preprocessor directive is used whenever the active configuration does not match the value of the preprocessor. In other words, the emulator displays "Make my day Color" whenever the active platform is "DefaultConfiguration," and displays "Hello World Gray" if the active platform is any other emulator platform. The //#endif preprocessor directive completes the preprocessor block.

You can test the preprocessor code by running the MIDlet using different emulator devices, as described in Changing the Emulator Platform.

Running Configurations

Configurations can be built and run individually or simultaneously.

Right-click the MyHelloMIDlet Project node and choose Run. Use the configuration combo box in the Toolbar to change the configuration to BlackWhiteDisplay. Choose Run again. Two emulators appear, one color and one gray. The gray emulator displays "Make my day Gray" and the color emulator displays "Make my day Color."

To build multiple configurations simultaneously, right-click on a project and choose Batch Build. In the dialog that opens, check the box next to each configuration you want to build.

To test a device on the fly, right-click on the project and choose Run With. In the dialog that opens, choose the emulator platform and device you want to run.

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