We need to generate in automatic (Aggregate) an unique id number to each participant

Why all this trouble?

The id number will be displayed in the ODK Collect(Android) form
generated...................

Then the participants will complete the survey

I am looking into the Collect apk and OpenRosa source files

public class InstanceUploaderTask extends AsyncTask<Long, Integer,
InstanceUploaderTask.Outcome>

Any thoughts are welcome........................

Will post the source code back to the Community