WatchThis.Controllers.SlideshowDriver.Previous C# (CSharp) Method

		public void Previous()
		{
			logger.Info("SlideshowDriver.Previous {0}", State);
			int index;
			if (_recentIndex.HasValue)
			{
				index = _recentIndex.Value - 1;
			}
			else
			{
				// The last item (-1) is currently being displayed. -2 is the previous item
				index = _recent.Count - 2;
			}
			if (index < 0)
			{
				return;
			}

            ResetTimer();
			_recentIndex = index;
			ShowImage(_recent[_recentIndex.Value]);
			PlatformService.InvokeOnUiThread( () => Viewer.UpdateUiState());
		}