How to get property of app object from classdef?

Hello,

Typically, I set/get the app object property (text, value) within the code of the app.

I would like to do this stuff from a classdef. Could you please show me how to do it?

Thank you in advance.

Answer 1

[Deepak]

Hi @Tien Trinh,

As I understand, you generally modify the properties of the app within the code of the app itself. Now, you want to know how to modify the properties of the app from a user-defined class in App Designer.

To accomplish this task, we must create a class using “classdef” in App Designer that will interact with the app. There should be “get” and “set” methods defined in the class to modify the app properties. Additionally, an instance of the class should be created in the “startupFcn” of the app to call the required class functions.

Below is the App Designer code for the same:

classdef AppController 
    properties 
        % Define any properties the class might need 
    end 
    
    methods 
        function obj = AppController() 
            % Constructor 
        end 
        
        function updateText(app, newText) 
            % Update the text property of the app 
            app.UIText.Text = newText; 
        end 
        
        function val = getValue(app) 
            % Get a value from the app 
            val = app.propertyName;  
        end 
        
        function setValue(app, newValue) 
            % Set a value in the app 
            app.propertyName = newValue; 
        end 
    end 
end 

function startupFcn(app) 
% Create an instance of the class 
controller = AppController(); 

% Update the text in the app 
controller.updateText(app, 'Hello, World!'); 

% Get a value from the app 
currentValue = controller.getValue(app); 
disp(['Current Value: ', num2str(currentValue)]); 

% Set a new value in the app 
controller.setValue(app, 42); 
end 

Please find attached the documentation of “startupFcn” in App Designer for reference:

https://www.mathworks.com/help/matlab/creating_guis/app-designer-startup-function.html

I hope you found this insightful.