Fix crash in fragment if getActivity() returns null.

			// n.b., fragments have to be static (as they might be inserted into a new Activity - see http://stackoverflow.com/questions/15571010/fragment-inner-class-should-be-static),

			// so we access the MainActivity via the fragment's getActivity().

			MainActivity main_activity = (MainActivity)this.getActivity();

			// activity may be null, see https://stackoverflow.com/questions/13116104/best-practice-to-reference-the-parent-activity-of-a-fragment

			// have had Google Play crashes from this

			if( main_activity != null ) {

				main_activity.setWindowFlagsForCamera();

				main_activity.showPreview(true);

				String new_save_location = this.getChosenFolder();

				main_activity.updateSaveFolder(new_save_location);

			}

			else {

				if( MyDebug.LOG )

					Log.e(TAG, "activity no longer exists!");

			}

			super.onDismiss(dialog);

		}

	}