ignore updateTorrents() and quickUpdateTorrent() if fragment is detached

app/src/main/java/org/transdroid/core/gui/TorrentsFragment.java

@@ -144,6 +144,10 @@ public class TorrentsFragment extends Fragment implements OnLabelPickedListener
 	 * @param newTorrents The new, updated list of torrents
 	 */
 	public void updateTorrents(ArrayList<Torrent> newTorrents, ArrayList<Label> currentLabels) {
+		if (this.isDetached()) {
+			return;
+		}
+
 		torrents = newTorrents;
 		this.currentLabels = currentLabels;
 		applyAllFilters();
@@ -155,6 +159,10 @@ public class TorrentsFragment extends Fragment implements OnLabelPickedListener
 	 * @param wasRemoved Whether the affected torrent was indeed removed; otherwise it was updated somehow
 	 */
 	public void quickUpdateTorrent(Torrent affected, boolean wasRemoved) {
+		if (this.isDetached()) {
+			return;
+		}
+
 		// Remove the old torrent object first
 		Iterator<Torrent> iter = torrents.iterator();
 		while (iter.hasNext()) {