Display error if groups information can not be retrieved.

app/src/main/java/org/communiquons/android/comunic/client/ui/fragments/NotificationsFragment.java

@@ -263,6 +263,12 @@ public class NotificationsFragment extends Fragment implements View.OnCreateCont
                     return;
                 }
 
+                //Check if we could not get information about related gropus
+                if(notifs.getGroupsInfo() == null){
+                    Toast.makeText(getActivity(), R.string.err_get_groups_info, Toast.LENGTH_SHORT).show();
+                    return;
+                }
+
                 //Save the list of notifications and display it
                 mNotificationsList = notifs;
                 displayNotificationsList();

app/src/main/res/values/strings.xml

@@ -201,4 +201,5 @@
     <string name="navigation_drawer_close">Close navigation drawer</string>
     <string name="action_personal_page">My Page</string>
     <string name="notif_on_group_page">on the page of the group %1$s</string>
+    <string name="err_get_groups_info">Could not get information about groups!</string>
 </resources>