firs, glad to hear that the problem is now solved.
if you are a beginner in Android, before starting the ImageTargets sample, you may want to familiarize a bit with some Android development topics (unless you're already OK with them), in particular:
- Android activities (in particular it is important to understand well the "activity lifecycle" concepts):
- AsyncTask: this is about running tasks in separate threads in Android, and it is used in our samples (typically for inititalization tasks, to avoid blocking the user interface for tasks that take some time to complete)
- Java Native Interface (JNI): this is a must (although you don't need to know it in full detail), as the Vuforia API is written in C++ and the Java code of the apps communicate with the C++ part by using JNI (by the way, each sample project contains a directory called "jni" where all the C++ code is included; this is a good link to start from:
- OpenGL: if you want to fully understand the samples (in particular the rendering code) you need to have at least a basic knowledge of OpenGL; the internet is full of tutorials about OpenGL programming for beginners
Then reading the ImageTargets code is an excellent way of learning Vuforia.
I hope this helps.