UPDATE: it is now also possible to create Android Live Wallpapers with Unity3d — check out the latest version of AJUnity2Eclipse!
Developing with Unity3d makes a lot of fun, not least because Unity dramatically simplifies the workflow when developing for multiple platforms. This is a huge benefit, especially when developing for different mobile platforms with many different screen sizes and device features. Unity already comes with a great framework to support most of these features. However from time to time, it can be useful to have the ability to write additional native code for a specific platform, namely Android and iOS. For example, we lately developed an app for one of our customers that had the requirement to display a login-screen on startup and user/role management on an additional screen. Of course this could be (somehow) done in Unity, but a native solution was clearly preferred. For iOS this was not a big problem, since Unity builds an Xcode project that can be extended easily. But for Android it was not that simple to get the whole thing to work in Eclipse. If you are familiar with the steps it takes (described here) to make Eclipse and Unity play together, you know how time consuming and error-prone it is. The most annoying part is that you have to copy the contents of the assets folder to your eclipse project, every time you make a change to your Unity project. And it is even worse if you have to integrate everything into your version control system.
Then – last week – we got a similar requirement for a new app and we agreed that this was not an optimal solution. So we decided to develop an Unity Editor Plugin that automizes the entire process and comes up with a one-click solution!
The Plugin adds a menu item to Unity to directly create an Eclipse Android project for your unity project. And the best thing: you no longer need to copy the assets folder! Once you continued working in Unity you can update your Eclipse project with one click! Of course this operation preserves any changes you made to the Eclipse project in the meantime.
We packaged the Plugin and made it available in the Unity Asset Store. After downloading, simply follow the instructions in the next section to set it up.
Using the AJUnity2Eclipse Plugin
First of all, download AJUnity2Eclipse Plugin from the Unity Asset Store and directly import it to your project. Alternatively, if you already downloaded a copy, you can simply pick the AJUnity2Eclipse.unitypackage file from your filesystem and drag it to the Project-Window in Unity.
Before your project can be exported to Eclipse, you initially need to make an Android-Build. Go to “File” -> “Build Settings ..”, select Android from the available platforms menu and click “Build”. Unity asks you to save the APK-file somewhere – you can save it anywhere, you won’t need it anymore. Once you have done this, click the new menu item named “Eclipse export ..” in the “File”-Menu. A small configuration dialog appears: you can leave all settings unchanged. You might want to change the output directory (the directory, where the Eclipse Projects are created – yes there are two projects), but we recommend to use the default, since this keeps your project well structured. Now finally click “Create Eclipse project”.
Note that AJUnity2Eclipse respects your Android Player Settinngs, like Bundle Identifier, Bundle Version and Minimum API Level, so your project is already well set up! By default, a directory called “eclipse-android” has been created in the root folder of your Unity project.
Now fire up Eclipse and go to “File” -> “Import…” -> “Android” -> “Existing Android Code into Workspace” and pick the newly created “eclipse-android” folder, or whatever you specified as output directory. By selecting this folder, you already see the two projects in the list box. Check them both and hit “Finish”. Important: it’s strongly recommended to not check the “Copy projects into workspace” option! Otherwise your assets will not be updated automatically when you make changes to the Unity project.
In some situations, you might see a small red exclamation mark in your package explorer or you might get build errors in Eclipse. To solve this issue, right click on the projects and select “Android Tools” -> “Fix Project Properties”. That’s it!
You can now build the Android project (the one that does not include the word “library” in its name) like you would do normally and test it on your device. The library-project includes the Unity Player binary files and is automatically referenced from your main project – you never have to touch or care about it.
Now you can add Java classes and change the main Activity to whatever you want. If you at any time go back to your Unity project and make some changes, you simply need to make an Android Build an run the export Plugin again. It automatically recognizes that you already created an Eclipse Project and offers you to update it with your latest Unity changes (like assets and scripts).
If you have any problems with the plugin, feel free to contact us or to leave a comment!