After the line
figImage = figure;
the variable figImage contains the handle of the figure. If you want to use this handle in a function, you have to provide it as input argument:
function main
figH = figure;
myVar = rand
setappdata(figH, 'myVar', myVar); % Store variable in figure
subFunction(figH);
end
function subFunction(figH)
myVar = getappdata(figH, 'myVar');
disp(myVar);
plot(1:10);
end
Usually the variables stored by setappdata() are used by callbacks of the figure:
function main
figH = figure;
myVar = rand;
setappdata(figH, 'myVar', myVar); % Store variable in figure
uicontrol(figH, 'Style', 'pushbutton', 'String', 'Click!', ...
'Callback', @myCallback);
end
function myCallback(buttonH, EventData)
figH = ancestor(buttonH, 'figure');
myVar = getappdata(figH, 'myVar');
disp(myVar);
end
Alternatively you could provide the handle of the figure as 3rd input argument:
... as above
uicontrol(figH, 'Style', 'pushbutton', 'String', 'Click!', ...
'Callback', {@myCallback, figH});
function myCallback(buttonH, EventData, figH)
% Not needed then: figH = ancestor(buttonH, 'figure');
The idea of setappdata is to store data inside a figure (or any other gui element), instead of using global variables. But if you use the root object, this is exactly the same as globals:
setappdata(groot, 'myVar', rand)
This has the same püroblem as globals: All functions can overwrite this variable. e.g. if you run multiple instances of the same GUI or if you run third-party software, which uses the same names by accident.
In your case the messge "Invalid or deleted object" means, that the variable figImage is still existing, but contains the handle of an already deleted figure or it is empty. Seeing your posted code, I cannot guess, why this is the case.
