Hello world

Introduction

Importing an existing project will help demonstrate the structure of a libgdx project, and also serves as an introduction into the development workflow.

Requirements

All that is required is Eclipse with the Android SDK installed. Go to the Android SDK Instructions webpage for more details.

Download and Import

Download the helloworld.zip source code at downloads page.

In Eclipse, go to File -> Import... -> General -> Existing Projects Into Workspace. In the Import Projects screen, click Select archive file, and browse to the helloworld.zip. After that, make sure the gdx-helloworld and gdx-helloworld-android projects are found and selected, then click Finish.

Running

The first project we'll look at, gdx-helloworld, is where the game's code is located. You can run it as a stand-alone Java Desktop application, that is, it requires no simulator or Android handset. To run the application, in your Package Explorer view, right click on the gdx-helloworld folder, select Run As -> Java Application. If a dialog pops up, asking for the main class, select HelloWorldDesktop. The Hello World desktop application should start up:

The gdx-helloworld-android project adds a thin layer of code ontop of gdx-helloworld to allow it to run on an Android device. If you look at its src source directory, you'll see that it contains very code. That's because the project references everything from gdx-helloworld. To run the application, in your Package Explorer view, right-click on the gdx-helloworld-android folder and select Run As -> Android Application. At this point, the application will be loaded and run on a compatible simulator (i.e. Android Virtual Device), or a Android device connected to the computer:

Going Forward

Since the Android simulator is too slow to properly test games with, being able to run the game as a desktop application helps streamline the development process. Developers avoid having to load the game onto a device every time they want to preview it. Furthermore, a team of developers and designers can more quickly test and share changes with one another.

You can experiment with this process by making some changes to gdx-helloworld project, then running it as a desktop application. When you're happy with the end result, see how your changes look on Android when by running gdx-helloworld-android. A more pain-free development process is just one of the advantages of libgdx. Keep an eye out for upcoming tutorials about the different features of libgdx.