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Okay, so I've seen a lot of questions like this here, but none of the provided answers seem to work for my particular case.

I have a game simulation program written in two parts; I wrote the actual functionality first, and then the GUI to display it all. I figured that when I was done I'd just implement calls back and forth to make the two talk to one another. The back-end used JOptionPane in the meantime to get user input.

My problem is that now that I want to display things in the GUI, I can't figure out how to pause the running of the program to wait for that to happen. For example, I had this in my original version:

private static void runAttackerTurn(Team off, Team def) {

int counter = 0;
while (counter < 4 && off.whoHasIt() != null) {
    //Do some stuff
    active = getActive(off, def, counter);
    select = (String)JOptionPane.showInputDialog(null, 
                    "Who Would " + active.getName() + " Like To Attack?" + "\n" +
                    off.whoHasIt().getName() + " has the ball",
                    "Turn " + turnCount + " - " + teamName + " Attacker Turn" ,
                    JOptionPane.INFORMATION_MESSAGE, null,
                    attackerOptions, attackerOptions[0]);
    target = getTarget(off, def, select, counter);
    attack((Forward)active, target);    
    //More stuff
    counter++;
}

}

And it worked just fine. But when I have a GUI that I'd like to use instead of JOptionPane it all breaks down. The GUI has a JPanel containing a JLabel for the text, a JComboBox for the list options, and a JButton to confirm. What I would like to do is have the program "pause", effectively, and wait for the user to hit the button, then take the selected item, put that in select and continue on.

I can't break the method up into two parts, as I originally tried, because I need to send other things besides just the result of select into the second part.

Also, it might not be apparent from the above, but I do this about twenty or thirty times in different methods over the course of the program, so I really need a general solution rather than a quick fix.

I thought doing this with multiple threads might work, but I can't seem to get that right (the main thread stops executing too early - the button doesn't even show up to be clicked) and anyway, I'd prefer something simpler.

Also, in case this isn't perfectly clear, what I am really trying to do is simulate the modal property of JOptionPane within a JPanel that's embedded in the GUI, and make the method wait for the user input before continuing.

Any ideas?

ThePerfectionist
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  • I suppose JOptionPane blocks UI because it modal dialog, if you need your layout to be modal - try this http://stackoverflow.com/questions/1481405/how-to-make-a-jframe-modal-in-swing-java. Also you can use multithread model - all you need is create new thread, call join() and wait user input. – Georgy Gobozov Dec 08 '12 at 23:28

1 Answers1

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The multiple thread approach might still be the easiest way to do it. If you don't actually need the program logic to keep going while the dialog comes up, and don't mind needing an extra thread with zero speed increase, you could just have a function in your actual game logic class called waitforinput() that just you just throw in after you call something on the GUI thread. Make it look something like this:

waitForInput()
{
   while(gotInput==false)
   {

   }
   gotInput=false;
   return;
}

Then have your GUI class flip the input variable whenever it finishes something that should resume the game. It's not pretty, but it's dirt simple and should work just fine for your purposes.

NathanTempelman
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    Busy loops are bad. You should use a synchronized `wait()`/`notify()` pair. – David R Tribble Apr 17 '13 at 21:17
  • Well obviously there are better ways to do it, but he didn't seem to be able to find them. This is probably the simplest, and seeing as this game probably has zero performance requirements it seems like it'd do the job just fine. – NathanTempelman Apr 18 '13 at 17:11