Check if fragment already has a view and is still attached

app/src/main/java/chat/rocket/android/chatroom/ui/ChatRoomFragment.kt

@@ -276,9 +276,11 @@ class ChatRoomFragment : Fragment(), ChatRoomView, EmojiKeyboardListener, EmojiR
     ) {
         // TODO: We should rely solely on the user being able to post, but we cannot guarantee
         // that the "(channels|groups).roles" endpoint is supported by the server in use.
-        setupMessageComposer(userCanPost)
-        isBroadcastChannel = channelIsBroadcast
-        if (isBroadcastChannel && !userCanMod) activity?.invalidateOptionsMenu()
+        ui {
+            setupMessageComposer(userCanPost)
+            isBroadcastChannel = channelIsBroadcast
+            if (isBroadcastChannel && !userCanMod) activity?.invalidateOptionsMenu()
+        }
     }
 
     override fun openDirectMessage(chatRoom: ChatRoom, permalink: String) {