Johannes - instead of using the ButtonDownFcn for the button, just use Callback. In this example, when the user presses the button, the callback fires and the userData is saved to a mat file (it can be adapted to save to the workspace if needed):
function FigureWithExportButton
fig_handle = figure;
myData.xData = rand(10,12000);
myData.yData = randn(10,1);
myData.sampleNames = {'Sample01','Sample02','Sample03','Sample04','Sample05',...
'Sample06','Sample07','Sample08','Sample09','Sample10'};
plot(myData.xData')
legend(myData.sampleNames);
set(fig_handle,'UserData',myData)
btn = uicontrol('Parent',gcf,'Style','pushbutton','string','Export userdata', 'Callback', @exportDataCallback);
function exportDataCallback(hObject, eventdata)
userData = get(hObject, 'UserData');
filename = [char(inputdlg('Please enter a file name:', 'Export UserData')) '.mat'];
save(filename, 'userData');
end
end
