Chronometer reset
When I played with the chronometer awhile back I just used the setBase() method to set the base to the current time just before calling start(). Depending on your exact needs you may need to add some logic around whether to reset the chronometer or not before starting it.
View.OnClickListener mStartButtonListener = new OnClickListener() { @Override public void onClick(View arg0) { mChronometer.setBase(SystemClock.elapsedRealtime()); mChronometer.start(); } };