Variables in GUIDE program mysteriously being reset

Hi, I'm relatively new to GUIDE, though I have used Matlab extensively before. In the OpeningFcn of my gui program, I declare a number of variables that need to be kept track of:

handles.output = hObject;
handles.TOFdata=[];
handles.Energies=[];
handles.times=[];
handles.SubNoise = true;
handles.CurrentPlottedEnergy = 0;
handles.masses=[];
handles.MassMultiplier=0;
handles.toffset = 0;

This mainly works fine. For instance, the handles.times vector is referenced many times throughout the program to update plots, and there's no trouble.

However, the last three variables above (masses, MassMultiplier, and toffset) seem to get reset any time I assign them. In a certain callback function I assign them values, and during the scope of that function, they are still in memory. But when a different callback references them, I find that they have been re-initialized to the values above.

Is there a maximum number of variables that can be held in this way? The line to set handles.masses=[]; is not executed except when launching the gui (which I verified by setting a breakpoint there). I cannot seem to locate where or why they are being reset.

I'd appreciate any help you can give. This is on R2011b. I can send the code if someone wants to try it themselves---just email me at [e-mail] (remove the 8s) and I will email the m file. Thanks

Answer 1

[Walter Roberson]

After you set the values and before the end of the function that sets them, make sure you have

guidata(hObject, handles)

Also if you have any routine in which you call a function that might change the values (including a pause() or drawnow() that might allow a callback to execute) and you need the (possibly) updated values after that point in the function, be sure to

handles = guidata(hObject);

in order to fetch the updated values.

[Reuben Gann]

Yes, that line is in the function after all of those assignments. I have 9 variables, but for some reason it's only those last three that have a problem.

I tried going through and adding "handles = guidata(hObject);" to any routine that modified the handles data. It unfortunately does not seem to have made a difference. Thanks, though.

[Walter Roberson]

handles = guidata(hObject) needs to go in any routine that needs to access updated handle data.

You could experiment by moving those lines higher up. I know the order should not make a difference but confirmation is always good.