Veena – After you execute the undo function, of course the undo stack will be empty because the undo command was already executed.

Can you please help me. I am using matlab 2017b.

I am using uiundo function for undo and redo feature. when the debugger is inside the uiundo function i can see UndoStack has the value.

but once i come out of uiundo function and execute below code:

% Retrieve redo/undo object
undoObj = getappdata(hFig,'uitools_FigureToolManager');
if isempty(undoObj)
   try
      % R2014a and earlier
      undoObj = uitools.FigureToolManager(hFig);
   catch
      % R2014b and newer
      undoObj = matlab.uitools.internal.FigureToolManager(hFig);
   end
   setappdata(hFig,'uitools_FigureToolManager',undoObj);
end

undoObj.CommandManager.peekundo

undostack is empty. Can you please help me to resolve the issue.

@John – I think you mean R2014b, not R2014a. In 14b the entire graphics engine changed (HG2) so this is not surprising. I updated the main post, but here is the relevant fix:

try
   % R2014a and earlier
   undoObj = uitools.FigureToolManager(hFig);
catch
   % R2014b and newer
   undoObj = matlab.uitools.internal.FigureToolManager(hFig);
end

thank you for your great guide! I implemented a redo/undo functionality in a small tool a couple of years ago, and it worked great … until now. Unfortunately, newer Matlab versions than 2014a don’t have the uitools_FigureToolManager object anymore, and I couldn’t find any alternatives. Do you (or anybody else) know if just the location has changed, or has the object completely been removed? Are there already any alternatives found to access Matlab’s redo/undo manager?

Best regards

@Jason – when you undo steps, you first need to undo all the actions that followed your desired undo-action, because they might affect the way your undone action behaves. Effectively, you are unrolling the actions at the exact reverse order in which they happened. If you look at any program with an undo list, they all behave the same way (try any editor, for example). I actually think it’s very intuitive.

Regarding the scrollable undo/redo lists – see the previous post for an example. The scrollbar appears automatically when more than 8 list items are available. This is standard JComboBox behavior (the number 8 is a modifiable property of the JComboBox).

Sorry for more updates, but here is my current solution

for i=length(undoObj.CommandManager.UndoStack):-1:num
   undoObj.CommandManager.undo;
end

This does what I need, but it requires cycling through all the previous changes. I’d rather just skip to the desired step, because for my gui, this process is pretty slow.

small update: I’ve gotten this to work partially by using:

undoObj.CommandManager.UndoStack(num).execute;

but the undoObj structure wont update to reflect the changes.

Thanks Again

Also, Do you know how to create the list box used in the function button or the cell button in the editor? its a context menu with a scroll bar on the side. I’d like to use that functionality for an undo dropdown.

Thanks for any help!
Jason

sorry for the irrevalent post here

thanks