Unable to access the values a user inputs into text boxes

Question

I am trying to collect several values inputted into NumericEditField controls by a user and store them in order to use them later in a computation, whose result gets presented back.

I seem to be able to store the variables, but am unable to access them later. Each of the variables is considered private because that is where it is having me add the callbacks. I have tried adding all of the variables in a public portion near the beginning, but that did not work.

Here is the code:

classdef Finalscalc < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure                       matlab.ui.Figure
        PleaseenteryourcurrentgradeEditFieldLabel  matlab.ui.control.Label
        PleaseenteryourcurrentgradeEditField  matlab.ui.control.NumericEditField
        PleaseenterthegradeyouwantEditFieldLabel  matlab.ui.control.Label
        PleaseenterthegradeyouwantEditField  matlab.ui.control.NumericEditField
        PleaseentertheweightofthefinalexamEditFieldLabel  matlab.ui.control.Label
        PleaseentertheweightofthefinalexamEditField  matlab.ui.control.NumericEditField
        Label                          matlab.ui.control.Label
        Label_2                        matlab.ui.control.Label
        Label_3                        matlab.ui.control.Label
        YouneedatleastaEditFieldLabel  matlab.ui.control.Label
        YouneedatleastaEditField       matlab.ui.control.NumericEditField
        Label_4                        matlab.ui.control.Label
        togetaEditFieldLabel           matlab.ui.control.Label
        togetaEditField                matlab.ui.control.NumericEditField
        Label_5                        matlab.ui.control.Label
        CalcualteButton                matlab.ui.control.Button
        GoodLuckLabel                  matlab.ui.control.Label
    end



    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)

        end

        % Value changed function: PleaseenteryourcurrentgradeEditField
        function PleaseenteryourcurrentgradeEditFieldValueChanged(app, event)
            app.current = app.PleaseenteryourcurrentgradeEditField.Value;
            current = app.current;
            app.current = current;
        end

        % Value changed function: PleaseenterthegradeyouwantEditField
        function PleaseenterthegradeyouwantEditFieldValueChanged(app, event)
            app.want = app.PleaseenterthegradeyouwantEditField.Value;
            want = app.want;
            app.want = want;
        end

        % Value changed function: 
        % PleaseentertheweightofthefinalexamEditField
        function PleaseentertheweightofthefinalexamEditFieldValueChanged(app, event)
            app.weight = app.PleaseentertheweightofthefinalexamEditField.Value;
            weight = app.weight;
            app.weight = weight;
        end

        % Button pushed function: CalcualteButton
        function CalcualteButtonPushed(app, event)
            grade = ((100 * app.want)-(100 - app.weight) * app.current) / app.weight;
            grade = app.grade;
            app.grade = grade;
        end

        % Value changed function: YouneedatleastaEditField
        function YouneedatleastaEditFieldValueChanged(app, event)
            grade = app.YouneedatleastaEditField.Value;
            fprintf('%,2f', grade); 
        end

        % Value changed function: togetaEditField
        function togetaEditFieldValueChanged(app, event)
            app.PleaseenterthegradeyouwantEditField.Value = app.togetaEditField.Value;

        end
    end

    % App initialization and construction
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure
            app.UIFigure = uifigure;
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';

            % Create PleaseenteryourcurrentgradeEditFieldLabel
            app.PleaseenteryourcurrentgradeEditFieldLabel = uilabel(app.UIFigure);
            app.PleaseenteryourcurrentgradeEditFieldLabel.HorizontalAlignment = 'right';
            app.PleaseenteryourcurrentgradeEditFieldLabel.Position = [117 337 174 22];
            app.PleaseenteryourcurrentgradeEditFieldLabel.Text = 'Please enter your current grade';

            % Create PleaseenteryourcurrentgradeEditField
            app.PleaseenteryourcurrentgradeEditField = uieditfield(app.UIFigure, 'numeric');
            app.PleaseenteryourcurrentgradeEditField.ValueChangedFcn = createCallbackFcn(app, @PleaseenteryourcurrentgradeEditFieldValueChanged, true);
            app.PleaseenteryourcurrentgradeEditField.Position = [306 337 100 22];

            % Create PleaseenterthegradeyouwantEditFieldLabel
            app.PleaseenterthegradeyouwantEditFieldLabel = uilabel(app.UIFigure);
            app.PleaseenterthegradeyouwantEditFieldLabel.HorizontalAlignment = 'right';
            app.PleaseenterthegradeyouwantEditFieldLabel.Position = [116 289 178 22];
            app.PleaseenterthegradeyouwantEditFieldLabel.Text = 'Please enter the grade you want';

            % Create PleaseenterthegradeyouwantEditField
            app.PleaseenterthegradeyouwantEditField = uieditfield(app.UIFigure, 'numeric');
            app.PleaseenterthegradeyouwantEditField.ValueChangedFcn = createCallbackFcn(app, @PleaseenterthegradeyouwantEditFieldValueChanged, true);
            app.PleaseenterthegradeyouwantEditField.Position = [309 289 100 22];

            % Create PleaseentertheweightofthefinalexamEditFieldLabel
            app.PleaseentertheweightofthefinalexamEditFieldLabel = uilabel(app.UIFigure);
            app.PleaseentertheweightofthefinalexamEditFieldLabel.HorizontalAlignment = 'right';
            app.PleaseentertheweightofthefinalexamEditFieldLabel.Position = [70 248 224 22];
            app.PleaseentertheweightofthefinalexamEditFieldLabel.Text = 'Please enter the weight of the final exam';

            % Create PleaseentertheweightofthefinalexamEditField
            app.PleaseentertheweightofthefinalexamEditField = uieditfield(app.UIFigure, 'numeric');
            app.PleaseentertheweightofthefinalexamEditField.ValueChangedFcn = createCallbackFcn(app, @PleaseentertheweightofthefinalexamEditFieldValueChanged, true);
            app.PleaseentertheweightofthefinalexamEditField.Position = [309 248 100 22];

            % Create Label
            app.Label = uilabel(app.UIFigure);
            app.Label.Position = [417 337 25 22];
            app.Label.Text = '%';

            % Create Label_2
            app.Label_2 = uilabel(app.UIFigure);
            app.Label_2.Position = [417 289 25 22];
            app.Label_2.Text = '%';

            % Create Label_3
            app.Label_3 = uilabel(app.UIFigure);
            app.Label_3.Position = [417 248 25 22];
            app.Label_3.Text = '%';

            % Create YouneedatleastaEditFieldLabel
            app.YouneedatleastaEditFieldLabel = uilabel(app.UIFigure);
            app.YouneedatleastaEditFieldLabel.HorizontalAlignment = 'right';
            app.YouneedatleastaEditFieldLabel.Position = [177 105 107 22];
            app.YouneedatleastaEditFieldLabel.Text = 'You need at least a';

            % Create YouneedatleastaEditField
            app.YouneedatleastaEditField = uieditfield(app.UIFigure, 'numeric');
            app.YouneedatleastaEditField.ValueChangedFcn = createCallbackFcn(app, @YouneedatleastaEditFieldValueChanged, true);
            app.YouneedatleastaEditField.Position = [291 105 19 22];

            % Create Label_4
            app.Label_4 = uilabel(app.UIFigure);
            app.Label_4.Position = [323 105 25 22];
            app.Label_4.Text = '%';

            % Create togetaEditFieldLabel
            app.togetaEditFieldLabel = uilabel(app.UIFigure);
            app.togetaEditFieldLabel.HorizontalAlignment = 'right';
            app.togetaEditFieldLabel.Position = [337 105 46 22];
            app.togetaEditFieldLabel.Text = 'to get a';

            % Create togetaEditField
            app.togetaEditField = uieditfield(app.UIFigure, 'numeric');
            app.togetaEditField.ValueChangedFcn = createCallbackFcn(app, @togetaEditFieldValueChanged, true);
            app.togetaEditField.Position = [390 105 16 22];

            % Create Label_5
            app.Label_5 = uilabel(app.UIFigure);
            app.Label_5.Position = [417 105 25 22];
            app.Label_5.Text = '%';

            % Create CalcualteButton
            app.CalcualteButton = uibutton(app.UIFigure, 'push');
            app.CalcualteButton.ButtonPushedFcn = createCallbackFcn(app, @CalcualteButtonPushed, true);
            app.CalcualteButton.Position = [271 168 100 22];
            app.CalcualteButton.Text = 'Calcualte';

            % Create GoodLuckLabel
            app.GoodLuckLabel = uilabel(app.UIFigure);
            app.GoodLuckLabel.Position = [287 30 70 22];
            app.GoodLuckLabel.Text = 'Good Luck !';
        end
    end

    methods (Access = public)

        % Construct app
        function app = Finalscalc

            % Create and configure components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            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

Answer 1

Instead of using the ...ValueChanged functions all you need to do is access the Value field of the various controls from which you want to get values. Replace the current private methods block you have with this:

methods (Access = private)

    % Button pushed function: CalcualteButton
    function CalcualteButtonPushed(app, ~)
      % Get values from edit fields:
        want = app.PleaseenterthegradeyouwantEditField.Value;
        weight = app.PleaseentertheweightofthefinalexamEditField.Value;
        current = app.PleaseenteryourcurrentgradeEditField.Value;          
      % Perform computation:
        needed = ( (100 * want) - (100 - weight) * current) / weight;
      % Write values to new edit fields:  
        app.YouneedatleastaEditField.Value = needed;
        app.togetaEditField.Value = want;
    end

end

In my humble opinion, TMW greatly managed to simplify the access of values from text fields in the new UIFigure system - from here it's just a matter of understanding how it works.