How To Extend the Unity Android Activity

This article explains how to integrate a QCAR Unity project for Android with the Eclipse IDE and how to extend the main activity. This procedure also enables you to add custom views over the Unity view, See: How To Add Views Over Unity for Android

Integration steps

  1. Create a Vuforia Unity project using the Unity Editor.
  2. Build the project for the Android platform; when doing so, open the "Player settings" and take note of the package name that you have chosen as your "Bundle Identifier" (e.g., "") and the Android API level (e.g., 2.3 "Gingerbread"), as you will reuse these settings later.
  3. Save the APK file when asked by Unity, giving it the name you want (name is not relevant).
  4. Use your file explorer to browse to your Unity project directory, where there is a folder called "/Temp" containing a subfolder called "/StagingArea." Open the StagingArea folder to see a set of files and directories (such as /res, /assets, /bin,  AndroidManifest.xml,...) as in a typical Android project.
  5. Copy the content of the StagingArea folder to another location on your file system (for instance, a location like "C:\Development\Android\Unity\MyVuforiaUnityProject" or similar). Any location is fine, as long as it is not under the original Temp folder of your Unity project.
  6. Open Eclipse, and create a new Android project "from existing source"; click Browse and point to the folder where you just copied the StagingArea content (see last step).
  7. Give the project a name, for instance, "QCARUnity."
  8. Right-click the QCARUnity project, select Properties, select Android and tick the "IsLibrary" checkbox (i.e., make the project a library); press Apply/OK.
  9. Create another new project and name it, for instance, "QCARJava"; be sure to select the same package name and the same API level that you previously selected when building your Unity project with the Unity Editor.
  10. Right-click the "QCARJava" project, select Properties > Java build Path > Libraries, click Add External Jars... and point to Editor\Data\PlaybackEngines\androidplayer\bin\classes.jar under your Unity installation directory, then press OK.
  11. Right-click QCARJava again and select Properties > Android, scroll the page down until you see a Reference Projects table, and add the "QCARUnity" project to the list of referenced projects.
  12. Move the "/assets" and "/libs" folders from the "QCARUnity" project directory to the "QCARJava" project folder.
  13. Copy Vuforia.jar and QCARUnityPlayer.jar from the "/plugins" directory of the "QCARUnity" project to the "/libs" folder of the "QCARJava" project.
  14. Copy the "/QCAR" folder (this should contain your Dataset .XML/.DAT files) from the "/raw" directory of the "QCARUnity"  project to the "/assets" folder of the "QCARJava" project.
  15. Copy the AndroidManifest.xml file from "QCARUnity" to the "QCARJava" project (overwrite the existingAndroidManifest.xml file).

Code changes

Finally, make the following small code changes in the main source file of the "QCARJava" project (where your main activity is defined):

  1. Make your main activity class (e.g., "QCARJavaActivity") extend from:
    QCARPlayerNativeActivity -- Vuforia 3.x
    UnityPlayerNativeActivity -- Vuforia 4.x
    (instead of extending from Activity).
  2. Press Ctrl+Shift+O to adjust the imports automatically.
  3. Remove the line "setContentView(R.layout.main)"
  4. Edit the AndroidManifest.xml file of your QCARJava project; replace the name of the main activity, which is set to one of the following:
    "com.qualcomm.QCARUnityPlayer.QCARPlayerNativeActivity" -- Vuforia 3.x
    "com.unity3d.player.UnityPlayerNativeActivity" -- Vuforia 4.x
    with the name of your actual main activity, e.g.:

Allow native events forwarding via the ForwardNativeEventsToDalvik setting in the manifest (must be set to true).

        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
      android:value="true" />

You are now ready to build and run your Android project in your device from Eclipse.

Tip: if you get ClassDefNotFound (or similar) runtime errors, you might need to perform this extra step:

  1. Go to the Project > Properties > Java Build Path > Order and Export tab, and check (tick) theclasses.jar, Android x.y and Android Dependencies items.
  2. Apply and rebuild the probject.