public void PauseOrResume()
{
logger.Info("SlideshowDriver.Pause: {0}", State);
if (State == DriverState.Paused)
{
Play();
}
else if (State == DriverState.Playing)
{
State = DriverState.Paused;
DestroyTimer();
}
PlatformService.InvokeOnUiThread( () => Viewer.UpdateUiState());
}