You'll have to call into the Java layer to do this.

In the [..]_renderFrame method look for ..

for(int tIdx = 0; tIdx < state.getNumActiveTrackables(); tIdx++)

The body of this loop is executed if any trackables are detected, or being tracked.

But keep in mind that Android Activities are run on a stack, so a new one will replace the calling activity at the top. If you simply want to overlay a view on the QCAR context, you can do this using addContentView() rather than utilizing a new activity.

I would infact like to open another activity rather than overlaying some 3D object. Let me know which line of code is responsible for this

No, sorry, that's closed source.

- Kim

I am just interested in how it's actually done.
Is this code available to see?

Yes, this is compiled in. If you let us know what you're trying to do we might be able to help.

- Kim