Embed Unity's project into custom android project as subview. Contains 2 different kind of subview . following the tutorial http://forum.unity3d.com/threads/using-unity-android-in-a-sub-view.98315/
Not gonna work on project with vuforia plugins . The discussion here: https://developer.vuforia.com/forum/android/qcarunityplayer-subview
should use the fragment since Android3.3 as a sub-activity.