GUI handles not updating with guidata

Hi all,

I have a GUI which initialises with:

handles.histFig = gobjects(0); % Return empty graphics array object
handles.histAxes = gobjects(0); % Return empty graphics array object 

guidata(hObject, handles);

I then have a call back function for a push button which either creates a set of axes in a figure window (separate from the GUI) or if it exists I want to update the figure with data and hence add more lines onto the axes. Once I step out of the callback the axes saved in handles vanished. The code:

function pushbutton_get_Callback(hObject, eventdata, handles)
if  isempty(handles.hAxes) || ~isgraphics(handles.hAxes) 
    handles.hFig = figure();
    handles.hAxes = axes('Parent', handles.hFig); 
    handles.v(1) = line(handles.hAxes, [0.000001,1], [90, 90], 'DisplayName', '90 kV', 'Color','red','LineStyle','--', 'LineWidth', 1.5);
    handles.v(2) = line(handles.hAxes, [0.000001,1], [100, 100], 'DisplayName', '100 kV','Color','blue','LineStyle','--', 'LineWidth', 1.5);
    xlabel(handles.hAxes, '% Distribution'); 
    ylabel(handles.hAxes, 'pk - pk Voltage [kV]');
    set(handles.hAxes, 'xscale','log', 'xlim',[0.000001,1], 'ylim', [70, 110],...
    'XGrid', 'On', 'YGrid', 'On', 'NextPlot',  'add');
    title(handles.hAxes,['IEP ',trainForm3], 'FontSize',14); %   
end

fileNames = cellstr(get(handles.textFile,'String'));     
file = fileNames{get(handles.textFile,'Value')};
v = abs(handles.finalData(2,:).'/1000);
[counts, edges]=histcounts(v, 'BinLimits', [0, 120],...
            'BinWidth', 0.2, 'Normalization', 'probability');         
binCentres = 0.5*(edges(1:end-1) + edges(2:end));
numPlots = numel(get(handles.histAxes, 'Children'));
handles.voltHist(numPlots + 1)= stairs(handles.hAxes, counts*100, binCentres, 'DisplayName', file);

   lgd= legend(handles.hAxes, 'Location','southoutside','Orientation','horizontal');
  guidata(hObject, handles);

So when I run the callback again, instead of the graph being updated with the new data stored in finalData, it creates a new plot.

I am not sure how to link the figure data to the GUI so that when I run the GUI callback it updates the figure by storing the values of handles.hAxes and handles.hFig. I do not see why it is not doing that if I am saving these in the handles structure.

Any pointers would be appreciated.

Cheers

[Rik]

Just to make sure: is the callback triggered on the figure that has the guidata associated with it?

[TJ]

The callback is triggered from the GUIDE created GUI. The figure that opens up in a seperate figure window which contains only a set of axes.

[Greg]

You initialize handles.histAxes then use handles.hAxes in the callback, but that should result in Reference to non-existent field errors...

If you put a breakpoint at the top of the callback, what does it say handles.hAxes contains on the first and second executions?