How to save all state in my App Designer app?

I have built an app for a specialized scientific analysis using App Designer. It is a complex interface with 8 tabs, and well over 100 controls. And it will grow.

It would be very helpful if I could provide my users with a "Save all settings" button. Question: is there a good way to programmatically enumerate all Components (as distinct from other properties or methods) in the app? And then, to read or set the value for each?

Answer 1

[Taylor]

Here's a basic overview of how you might go about that https://www.mathworks.com/matlabcentral/answers/523768-how-to-save-restore-state-of-app-designer-app

Answer 2

[Ken]

That example was half the answer, but it required enumerating the components to be saved, which doesn't grow well. I wanted to automatically traverse the app data structure and FIND programmatically all components whose values should be saved. Here's what worked for me. This solution will restore all components that match, leave alone all components that are not found in the saved data, and warn (in the Matlab window) of any saved state that did not match a component in the program.

This creates a robust save/load mechanism that will not crash even in the presence of version changes that add or delete components.

function SaveSettings(app)
    state = struct();
    props = properties(app);
    for i = 1:length(props)
        name = props{i};
        comp = app.(name);  % May be a component or a property, so far...
        c = string(class(comp));  
        if c == "matlab.ui.control.NumericEditField" ...
                || c == "matlab.ui.control.EditField" ...
                || c == "matlab.ui.control.CheckBox"
            state.(name)= comp.Value;
        elseif c == "matlab.ui.control.DropDown"
            % These are weird, had to be specially handled to save a string
            % instead of an index into the list:
            v = comp.Value;
            state.(name)= comp.Items{v};
        end
    end
    save('SavedSettings.mat','state');
end


function LoadSettings(app)
    load('SavedSettings.mat', 'state')
    fields = fieldnames(state);
    for i = 1:length(fields)
        name = fields{i};
        try   % or could use isprop(app, name) to test presence
            comp = app.(name);
            comp.Value = state.(name);
        catch err
            disp(['Did not use saved field', name, ': ', err.identifier])
        end
    end
end