Displaying figures/message boxes in a while loop

I'm having trouble displaying information to the user of my program. I want to have a figure or messagebox that comes up once when two different possibilities become true. The problem is that these can become true or false at any given time under certain circumstances, and the calculations are taking place inside a while loop. Also, while the two conditions are true - with the way I'm doing it now, the figure message box pops up during each iteration. I only want this to come up once. Any suggestions or advice would be greatly appreciated. Here is an example of my code.

   while (expression)
   %CALCULATIONS.......  
if AceHearts && KingHearts == true
    msgbox('Your odds of winning are 67%')
elseif AceHearts && KingClubs == true
    msgbox('Your odds of winning are 65%')
end

Answer 1

[Jan]

What about using a flag:

messageShownAlready = false;
while (expression)
  %CALCULATIONS.......  
  if AceHearts && KingHearts == true
    if ~messageShownAlready
      msgbox('Your odds of winning are 67%')
      messageShownAlready = true;
    end

    elseif AceHearts && KingClubs == true
      if ~messageShownAlready
        msgbox('Your odds of winning are 65%')
        messageShownAlready = true;
      end
    end
  end

[Ryan]

Thanks, this does solve the problem I was having with the messagebox coming up hundreds of times. But, basically while the program is running I want to be able to bring up the appropriate message box for any combination of cards (so if I replace both cards with different ones during the program) and have a new messagebox pop up. With this way, if I change the cards during the program a new msg will not come up since messageShownAlready is still true.

I tried solving this problem by using this code following code, but it did not work.

x = sum(sum(Card1));
y = sum(sum(Card2));
if x < 300 && y < 300
  MessageShownAlready == false
end

My thought process for this was, if both cards are removed, there will mainly be all black pixels, so if that happens - reset the flag back to false, then go about the program again. For some reason this doesn't work, and I feel like it should.

[Jan]

This is a comparison, not an assignment:

MessageShownAlready == false

Perhaps you mean:

MessageShownAlready = false

with one equal character.

[Image Analyst]

Please explain why you aren't using uiwait() like I suggested in my answer. That will still let each message box come up, like you want, but it will prevent hundreds of them coming up all at once: "the problem I was having with the messagebox coming up hundreds of times." msgbox() does not wait for you to click OK while wrapping it in uiwait() makes it wait for you.

There is a 'modal' input argument option but it doesn't seem to work according to the definition the rest of the world uses (i.e. it doesn't cause it to wait). If you just want all the messages to go to the command window instead of piling up hundreds of message boxes on the screen (which must all be clicked to clear them), you can use fprintf() instead of msgbox().

Answer 2

[Image Analyst]

Wrap msgbox() or helpdlg() in a uiwait() so it will wait for the user to click OK on it.

uiwait(helpdlg('blah blah blah'));

or better yet, use questdlg().

promptMessage = sprintf('Do you want to Continue processing,\nor Cancel to abort processing?');
titleBarCaption = 'Continue?';
buttonText = questdlg(promptMessage, titleBarCaption, 'Continue', 'Cancel', 'Continue');
if strcmpi(buttonText, 'Cancel')
  return;
end

so the user can bail out if they want.

[Ryan]

Thanks Image Analyst, that works perfect for what I'm trying to do!

[Image Analyst]

You're welcome. If it's the best answer, you can click the link to "Accept this answer". Thanks in advance.