SAMT takes your coordinates and today's date and works out the sun's angle at dawn, noon, mid-afternoon, sunset, and dusk — the astronomical events every calculation method is actually built on. Change your location, calibration finishes, and the times update immediately. No connectivity required at any point.
Set once in Settings — every screen respects it.
Plus Standard or Hanafi convention for Asr — Hanafi sets the shadow-length threshold later in the afternoon.