uieditfield defined in classdef won't update Value

I'm creating an app defined within a class. I click a uibutton and within it's callback select a directory. I want to update the Value field in my uieditfield to display the path to the directory, but the text isn't appearing in the edit field.

classdef MyClass
    properties
        mainfig
        mapgrid
        dirbutton
        dirdisplay
    end
    
    methods
        function obj = MyClass()
            obj.mainfig = uifigure();
            obj.mapgrid = uigridlayout(obj.mainfig, [1 1]);
            obj.dirbutton = uibutton(obj.mapgrid);
            obj.dirbutton.ButtonPushedFcn = @obj.dirbutton_callback;
            obj.dirdisplay = uieditfield(obj.mapgrid);
            obj.dirdisplay.Placeholder = "(Choose a directory)";
        end
        
        function dirbutton_callback(obj, src, event)
            thisdir = uigetdir(pwd, 'Select a folder');
            if thisdir == 0
                disp('No directory selected. Exiting script...')
                return
            end
            
            obj.dirdisplay.Value = thisdir;
        end
    end
end

How do I get the displayed text to update?

Answer 1

[Umang Pandey]

Hi Alex,

I understand that on clicking the button and selecting the directory, you intend to reflect the path to selected directory in the "uieditfield."

The reason behind the code not updating the "uieditfield" is because "MyClass" is a value class. It has not inherited a handle class in the class declaration. In MATLAB, the "< handle" syntax is used to indicate that a class is a handle class. A handle class allows multiple variables to refer to the same object, and changes made to the object through one variable will be reflected in all other variables that reference the same object. This is in contrast to value classes, where each variable has its own independent copy of the object.

You can incorporate the following change in your code to get it working:

classdef MyClass < handle
    properties
        mainfig
        mapgrid
        dirbutton
        dirdisplay
    end
    
    methods
        function obj = MyClass()
            obj.mainfig = uifigure();
            obj.mapgrid = uigridlayout(obj.mainfig, [1 1]);
            obj.dirbutton = uibutton(obj.mapgrid);
            obj.dirbutton.ButtonPushedFcn = @obj.dirbutton_callback;
            obj.dirdisplay = uieditfield(obj.mapgrid);
            obj.dirdisplay.Placeholder = "(Choose a directory)";
        end
        
        function dirbutton_callback(obj, src, event)
            thisdir = uigetdir(pwd, 'Select a folder');
            if thisdir == 0
                disp('No directory selected. Exiting script...')
                return
            end
            
            obj.dirdisplay.Value = thisdir;
        end
    end
end

To learn more about Handle classes, you can refer to the following documentation:

https://www.mathworks.com/help/matlab/handle-classes.html

Hope this helps!

Best,

Umang

[Umang Pandey]

Hi Alex, do consider accepting/upvoting the answer if it is was helpful.

Best,

Umang