MATLAB: Edit field in app designer

Question

Hello!

I'm trying to fill the "spottedRegions" edit field with the number of objects. In the simple script this already works for me with the output of N_objects (number of objects):

imageRGB = imread('shapes.jpg');
imageGray = rgb2gray(imageRGB);
imageBinary = imbinarize(imageGray); figure; imshow(imageBinary); title('Binary Image');
[B,~,~] = bwboundaries(imageBinary);
N_objects = length(B)-1           % number of shapes

shapes.jpg

I have done little in the App Designer so far. How do I get the N_objects displayed in my output field for "spottedRegions" – meaning after I hit OpenRGBimage?

The function for this button:

        function OpenButtonPushed(app, event)
            imageRGB = imread('shapes.jpg');
            imshow(imageRGB, 'Parent', app.UIAxes);            
        end
 

Full code in app designer:

        classdef shapesProperties < matlab.apps.AppBase
    % Properties that correspond to app components
    properties (Access = public)
        UIFigure                      matlab.ui.Figure
        CreateBinaryImageButton       matlab.ui.control.Button
        OpenButton                    matlab.ui.control.Button
        spottedRegionsEditField       matlab.ui.control.EditField
        spottedRegionsEditFieldLabel  matlab.ui.control.Label
        regionIndexSpinner            matlab.ui.control.Spinner
        regionIndexSpinnerLabel       matlab.ui.control.Label
        UIAxes2                       matlab.ui.control.UIAxes
        UIAxes                        matlab.ui.control.UIAxes
    end
    methods (Access = public)
       
    end
   
    % Callbacks that handle component events
    methods (Access = private)
        % Button pushed function: OpenButton
        function OpenButtonPushed(app, event)
            imageRGB = imread('shapes.jpg');
            imshow(imageRGB, 'Parent', app.UIAxes);            
        end
        % Button pushed function: CreateBinaryImageButton
        function CreateBinaryImageButtonPushed(app, event)
            imageRGB = imread('shapes.jpg');
            % RGB --> Graustufen
            imageGray = rgb2gray(imageRGB);
            % Graustufen --> Binärbild (Schwarz/Weiß)
            imageBinary = im2bw(imageGray);
            imshow(imageBinary, 'Parent', app.UIAxes2);
           
        end
        % Value changed function: spottedRegionsEditField
        function spottedRegionsEditFieldValueChanged(app, event)
            value = app.spottedRegionsEditField.Value;
            % value = N_objects  ???? 
        end
    end
    % Component initialization
    methods (Access = private)
        % Create UIFigure and components

        function createComponents(app)
            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'MATLAB App';
            % Create UIAxes
            app.UIAxes = uiaxes(app.UIFigure);
            title(app.UIAxes, 'RGB Image')
            app.UIAxes.Visible = 'off';
            app.UIAxes.Position = [16 283 300 185];
            % Create UIAxes2
            app.UIAxes2 = uiaxes(app.UIFigure);
            title(app.UIAxes2, 'Binary Image')
            app.UIAxes2.Visible = 'off';
            app.UIAxes2.Position = [315 283 300 185];
            % Create regionIndexSpinnerLabel
            app.regionIndexSpinnerLabel = uilabel(app.UIFigure);
            app.regionIndexSpinnerLabel.HorizontalAlignment = 'right';
            app.regionIndexSpinnerLabel.Position = [366 230 68 22];
            app.regionIndexSpinnerLabel.Text = 'regionIndex';
            % Create regionIndexSpinner
            app.regionIndexSpinner = uispinner(app.UIFigure);
            app.regionIndexSpinner.Position = [449 230 69 22];
            % Create spottedRegionsEditFieldLabel
            app.spottedRegionsEditFieldLabel = uilabel(app.UIFigure);
            app.spottedRegionsEditFieldLabel.HorizontalAlignment = 'right';
            app.spottedRegionsEditFieldLabel.Position = [143 230 89 22];
            app.spottedRegionsEditFieldLabel.Text = 'spottedRegions';
            % Create spottedRegionsEditField
            app.spottedRegionsEditField = uieditfield(app.UIFigure, 'text');
            app.spottedRegionsEditField.ValueChangedFcn = createCallbackFcn(app, @spottedRegionsEditFieldValueChanged, true);
            app.spottedRegionsEditField.Position = [247 230 40 22];
            % Create OpenButton
            app.OpenButton = uibutton(app.UIFigure, 'push');
            app.OpenButton.ButtonPushedFcn = createCallbackFcn(app, @OpenButtonPushed, true);
            app.OpenButton.Position = [12 230 108 22];
            app.OpenButton.Text = 'OpenRGB-Image';
            % Create CreateBinaryImageButton
            app.CreateBinaryImageButton = uibutton(app.UIFigure, 'push');
            app.CreateBinaryImageButton.ButtonPushedFcn = createCallbackFcn(app, @CreateBinaryImageButtonPushed, true);
            app.CreateBinaryImageButton.Position = [12 184 123 22];
            app.CreateBinaryImageButton.Text = 'CreateBinary-Image';
            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end
    % App creation and deletion
    methods (Access = public)
        % Construct app
        function app = shapesProperties
            % Create UIFigure and components
            createComponents(app)
            % Register the app with App Designer
            registerApp(app, app.UIFigure)
            if nargout == 0
                clear app
            end
        end
        % Code that executes before app deletion
        function delete(app)
            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Thank you very much in advance!

Michael

Answer 1

 app.spottedRegionsEditField.Value=N_objects;

You need to put this in OpenButtonPushed (along with the code to calculate N_objects).