ConcurrentModification Exception when adding items to a list

Troubleshooting gui
1

Hey guys.



I’m trying to implement a game browser with nifty but I’m receiving ConcurrentModification exceptions when I’m adding items to the list.

The following is the code where I add game-names to a list.

[java]private void updateGameList() {



ListBoxControl lobbygameList = screen.findControl(“listBoxStatic”, ListBoxControl.class);

//receives a List

List<GamesListGameMessage> gameList=StaticData.getCustomGamesList().getGames();



if (gameList.size() > 0) {

for (GamesListGameMessage e : gameList) {

lobbygameList.addItem(" " + e.getGameId() + "t t "

  • e.getHostNick() + "t t" + e.getUserCount() + "/"
  • e.getUserMax()); //

    }

    } else {

    lobbygameList.addItem("No games available");

    }

    }[/java]



    and this is the xml part:

    [xml]

    <panel id="listBoxPanel" childLayout="vertical" width="100%" height="70%" padding="30px,30px,30px,30px">

    <control id="listBoxStatic" name="listBox">

    <panel id="listBoxStaticData" width="100%" childLayout="vertical" visibleToMouse="true" />

    </control>

    </panel>

    [/xml]



    Things I already tried out:
  • when I start adding simple integer values to the list (1…10) I receive the exception after the second integer.
  • the method doesnt get called twice



    Any suggestions would be greatly appreciated.



    Kaizo



    EDIT: I should add that updateGameList() gets called when I click on a refresh button at the bottom of the screen.
2

Only thing that comes to my mind is that the lobbygameList is probably being iterated else where in the mean time.

Maybe Nifty iterate over it to refresh it?

3

The button is a nifty button or an AWT button? In the latter case you have a threading problem.

4

It is a nifty button. I will try to create a testcase.



One more thing: Sometimes it does work when I’m only adding one item to the list and I’m not pressing the button in rapid succession. Only sometimes though :frowning:

5

Small update:

The testcase worked without any problems. It probably IS a threading problem since I forgot to mention that the method doesn’t get called directly by the button. The button sends a request for a game list which THEN sends a notice to nifty when it has been received. I would’ve never imagined that this small detour creates such a big problem.



Now I need a new desk. In the last few days the bitemarks have taken over the majority of it… arrrgh



EDIT:

Alright I think I’ve solved it.

I used the following code:

[java]

nifty.delayedMethodInvoke(new NiftyDelayedMethodInvoke(){

@Override

public void performInvoke(Object… arg0) {

updateGameList();

}

}, null);[/java]



I hope this doesn’t cause problems in the long run.