Android trace file created but zero bytes long

The problem seems to have been that the stopMethodTracing() call which I had put in the onDestroy() method (as suggested in the Dev Guide) failed to stop the tracing even though I had tried three different means of ending the activity ... rotating the screen, pressing the Home Key and using Taskiller to kill the app.

By moving the stopMethodTracing() elsewhere I now have a trace with data in it!

(The vital clue was that I noticed that LogCat was reporting TRACE STARTED but never reported TRACE STOPPED.)