display invite again menu item for offline members

src/main/java/eu/siacs/conversations/ui/ConferenceDetailsActivity.java

@@ -380,10 +380,14 @@ public class ConferenceDetailsActivity extends XmppActivity implements OnConvers
 				MenuItem removeAdminPrivileges = menu.findItem(R.id.remove_admin_privileges);
 				MenuItem removeFromRoom = menu.findItem(R.id.remove_from_room);
 				MenuItem banFromConference = menu.findItem(R.id.ban_from_conference);
+				MenuItem invite = menu.findItem(R.id.invite);
 				startConversation.setVisible(true);
 				if (contact != null) {
 					showContactDetails.setVisible(true);
 				}
+				if (user.getRole() == MucOptions.Role.NONE) {
+					invite.setVisible(true);
+				}
 				if (self.getAffiliation().ranks(MucOptions.Affiliation.ADMIN) &&
 						self.getAffiliation().outranks(user.getAffiliation())) {
 					if (mAdvancedMode) {
@@ -404,7 +408,7 @@ public class ConferenceDetailsActivity extends XmppActivity implements OnConvers
 				}
 			} else {
 				MenuItem sendPrivateMessage = menu.findItem(R.id.send_private_message);
-				sendPrivateMessage.setVisible(true);
+				sendPrivateMessage.setVisible(user.getRole().ranks(MucOptions.Role.PARTICIPANT));
 			}
 
 		}

src/main/res/menu/muc_details_context.xml

@@ -8,6 +8,10 @@
         android:id="@+id/action_contact_details"
         android:title="@string/action_contact_details"
         android:visible="false"/>
+    <item
+        android:id="@+id/invite"
+        android:title="@string/invite_again"
+        android:visible="false"/>
     <item
         android:id="@+id/send_private_message"
         android:title="@string/send_private_message"

src/main/res/values/strings.xml

@@ -648,4 +648,5 @@
 	<string name="conference_subject">Subject</string>
 	<string name="choose_participants">Choose participants</string>
 	<string name="creating_conference">Creating conference…</string>
+	<string name="invite_again">Invite again</string>
 </resources>