This video shows what I mean. I didn't show it in the video, but starting, stopping, and saving or discarding the activity does not restart the datafield either.
https://youtu.be/ldLJzyG7G3k
I'm not sure what the expected behavior would be, but my personal expectation is that it should stop the data field upon exit of the Activity.
The DataField runs onStop in the case where I cycle through the various activities and the sensor number resets. It does not run onStop in the cases where I just exit the activity and reenter it.
function onStop(state) {
mView = null;
Sys.println("Running onStop");
releaseSensor();
}