GUI refuses to close after starting a loop within it, only closes when I attempt to close MATLAB entirely

I'm trying to make the GUI for a hydroponics system for one of my engineering classes, I have very little experience with MATLAB, especially so in making GUIs, so I'm trying to tackle problems one step at a time. Right now, that's closing the GUI without waiting forever, as it's making the troubleshooting process way longer than it needs to be.

Every time I try to close the figure by clicking the X at the top right of the window (specifically, after I hit the ON/OFF button at least once), it seems to ignore it. When this is happening, I can't run any new processes in the App Designer or Commmand Window. I can't close the app unless if I try to close MATLAB entirely, in which it won't initially do anything until a prompt appears that says "An operations is in progress. If the operation does not finish in 20 seconds, MATLAB will stop the operation and exit."

I've tried a ton of fixes from other kind of similar cases I've found in this forum, and none of what I've found seems to do anything significant. There's a lot of commented out stuff I have in this code, which is either old code that I've replaced or code that I can't/don't want to use yet. Any idea what could be wrong here or what to fix?

EDIT: also worth noting, this project is due in less than a week. It's been 4 weeks now and I feel like I have almost no progress, I wish I could say it comes down to procrastination. The sooner a response the better, I feel like a sitting duck right now.

classdef HydroponicsDraft < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure                     matlab.ui.Figure
        TabGroup2                    matlab.ui.container.TabGroup
        MAINTab                      matlab.ui.container.Tab
        AutomaticManualSwitch        matlab.ui.control.Switch
        AutomaticManualSwitchLabel   matlab.ui.control.Label
        TestLabel                    matlab.ui.control.Label
        SecondsEditFieldLabel        matlab.ui.control.Label
        SecondsEditField             matlab.ui.control.NumericEditField
        MinutesEditFieldLabel        matlab.ui.control.Label
        MinutesEditField             matlab.ui.control.NumericEditField
        HoursEditField               matlab.ui.control.NumericEditField
        HoursEditFieldLabel          matlab.ui.control.Label
        RunUntilDatePicker           matlab.ui.control.DatePicker
        RunUntilDatePickerLabel      matlab.ui.control.Label
        ONOFFButton                  matlab.ui.control.StateButton
        HYDROPONICSSYSTEMLabel       matlab.ui.control.Label
        MANUALTab                    matlab.ui.container.Tab
        NOTEADDPHSERVOCONTROLLabel   matlab.ui.control.Label
        ResetdefaultvaluesButton     matlab.ui.control.Button
        SetasdefaultvalveflowrateButton  matlab.ui.control.Button
        SetasdefaultpumpspeedButton  matlab.ui.control.Button
        ServoToggleButton            matlab.ui.control.StateButton
        ValveToggleButton            matlab.ui.control.StateButton
        PumpToggleButton             matlab.ui.control.StateButton
        CurrentPositionGauge         matlab.ui.control.LinearGauge
        CurrentPositionGaugeLabel    matlab.ui.control.Label
        CurrentFlowrateGauge         matlab.ui.control.LinearGauge
        CurrentFlowrateGaugeLabel    matlab.ui.control.Label
        CurrentSpeedGauge            matlab.ui.control.LinearGauge
        CurrentSpeedGaugeLabel       matlab.ui.control.Label
        ServoPositionSlider          matlab.ui.control.Slider
        ServoPositionSliderLabel     matlab.ui.control.Label
        PumpSpeedSlider              matlab.ui.control.Slider
        PumpSpeedSliderLabel         matlab.ui.control.Label
        ValveFlowrateSlider          matlab.ui.control.Slider
        ValveFlowrateSliderLabel     matlab.ui.control.Label
        DATAHISTORYTab               matlab.ui.container.Tab
        UIAxes_3                     matlab.ui.control.UIAxes
        UIAxes_2                     matlab.ui.control.UIAxes
        UIAxes                       matlab.ui.control.UIAxes
        DATASTATUSTab                matlab.ui.container.Tab
        pHDataToggleButton           matlab.ui.control.StateButton
        VolumeDataToggleButton       matlab.ui.control.StateButton
        TempDataToggleButton         matlab.ui.control.StateButton
        TempGauge_3                  matlab.ui.control.LinearGauge
        TempGauge_3Label             matlab.ui.control.Label
        pHLabel                      matlab.ui.control.Label
        VolumeGauge                  matlab.ui.control.LinearGauge
        VolumeGaugeLabel             matlab.ui.control.Label
        UIAxes2                      matlab.ui.control.UIAxes
    end


    properties (Access = private)
        a1          % main arduino
        a2          % pump arduino
        therm       % thermistor

        R2 = 10000;         % the value of the precision resistor
        temp0 = 298.15;     % reference temperature (25 C), in Kelvin
        res0 = 10000;       % resistance at reference temperature, in Ohms
        B = 3950;           % thermistor B parameter, in Kelvin

        pumpDef = 0.5;                  % default pump speed
        valveDef = 0.5;                 % default valve speed
        interval = minutes(30);         % interval of data collection

        currTime
        dataTime
        temp
        upFloat

        lowFloat
        onSwitch
        setTime
        autoSwitch
        pumpSwitch
        pumpSlider
        valveSwitch
        valveSlider
        servoSwitch
        servoSlider
        tempSwitch
        visionSwitch
    end


    % Callbacks that handle component events
    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)
            %app.a1 = arduino('COM5','Uno'); % connects to main arduino
            %app.a2 = arduino('COM6','Uno'); % connects to pump arduino
            %app.s = servo(app.a1, 'D6', 'MinPulseDuration', 533*10^-6, 'MaxPulseDuration', 2425*10^-6);
            app.a1 = arduino();
        end

        % Value changed function: ONOFFButton
        function ONOFFButtonValueChanged(app, event)
            % STATUSES
            app.onSwitch = app.ONOFFButton.Value;
            app.currTime = datetime(now,'ConvertFrom','datenum'); % current date
            app.setTime = app.RunUntilDatePicker.Value + hours(app.HoursEditField.Value)...
                + minutes(app.MinutesEditField.Value) + seconds(app.SecondsEditField.Value); % length of time to run system
            app.dataTime = app.currTime + app.interval; % when to collect data
            app.autoSwitch = app.AutomaticManualSwitch.Value;
            app.temp = 70; % temperature
            app.upFloat = 0; % upper sump float switch
            app.lowFloat = 0; % lower sump float switch 


            % Input Placeholders (Until actual inputs are hooked up)
            app.pumpSwitch = 1; % pump button
            app.pumpSlider = 0.5; % pump slider
            app.valveSwitch = 1; % valve button
            app.valveSlider = 0.5; % valve slider
            app.servoSwitch = 1; % servo button
            app.servoSlider = 0.5; % servo slider
            app.tempSwitch = 1; % temp button
            app.visionSwitch = 1; % vision system button


            disp('onSwitch:');
            disp(app.onSwitch);
            disp('RunUntilDatePicker.Value:');
            disp(app.RunUntilDatePicker.Value);
            disp('currTime:');
            disp(app.currTime);
            disp('setTime:');
            disp(app.setTime);
            disp('autoSwitch:');
            disp(app.autoSwitch);
            disp('upFloat:');
            disp(app.upFloat);
            disp('dataTime:');
            disp(app.dataTime);

            while 1
                if app.onSwitch == 0
                    break;
                end
                app.setTime = app.RunUntilDatePicker.Value + hours(app.HoursEditField.Value)...
                    + minutes(app.MinutesEditField.Value) + seconds(app.SecondsEditField.Value); % length of time to run system
                if ~isdatetime(app.RunUntilDatePicker.Value)
                    % insert invalid date input condition
                    continue;
                end
                app.currTime = datetime(now,'ConvertFrom','datenum'); % current date
                if app.currTime < app.setTime
                    continue;
                end
                if (datetime(app.currTime) > datetime(app.dataTime)) | ((datetime(app.currTime) == datetime(app.dataTime)) & (hour(app.currTime) > hour(app.dataTime)))
                    % insert data collection
                    app.dataTime = app.dataTime + app.interval;
                end
                app.autoSwitch = app.AutomaticManualSwitch.Value;
                switch app.autoSwitch
                    case 1
                        if app.temp > 90
                            continue;
                        end
                        if app.upFloat == 1
                            writeDigitalPin (app.a1,'D13',1); % red light on
                            writeDigitalPin (app.a1,'D12',0); % green light off
                            % insert upper sump float trigger condition
                            continue;
                        end
                        if app.lowFloat == 1
                            % insert lower sump float trigger condition
                            writeDigitalPin (app.a1,'D12',1); % red light on
                            writeDigitalPin (app.a1,'D13',0); % green light off
                            continue;
                        end
                        writeDigitalPin (app.a1,'D12',0); % red light off
                        writeDigitalPin (app.a1,'D13',1); % green light on
                        % insert default condition for valve and pump
                    case 0
                        if app.pumpSwitch == 1
                            % insert pump control with pumpSlider value
                        else
                            % insert pump off toggle
                        end
                        if app.valveSwitch == 1
                            % insert valve control with valveSlider
                        else
                            % insert valve closed toggle
                        end
                        if app.servoSwitch == 1
                            % insert servo control with servoSlider
                        else
                            % insert valve default position toggle
                        end
                        if app.tempSwitch == 1
                            % insert temp data display toggle
                        else
                            % insert temp = N/A and data display pause
                        end
                end






                % OLD CODE BELOW
                
                %                 % ON/OFF BUTTON UPDATES
                %                 app.onSwitch = app.ONOFFButton.Value;
                %                 if app.onSwitch == 1
                %                     if isdatetime(app.RunUntilDatePicker.Value)
                %                         % TIME CALCULATIONS AND UPDATES
                %                         app.currTime = datetime(now,'ConvertFrom','datenum'); % current date
                %                         app.setTime = app.RunUntilDatePicker.Value + hours(app.HoursEditField.Value)...
                %                             + minutes(app.MinutesEditField.Value) + seconds(app.SecondsEditField.Value); % length of time to run system
                %                         if app.currTime < app.setTime
                %                             app.autoSwitch = app.AUTOMANUALTOGGLEButtonGroup.SelectedObject.Text;
                %                             app.TestLabel.Text = app.autoSwitch;
                %                             if app.autoSwitch == 1          % AUTOMATIC MODE
                %                                 if app.temp < 90 && app.upFloat == 0 && app.lowFloat == 0
                %                                     % OFF UNTIL TESTABLE
                %                                     %writeDigitalPin (a2,'D11',pumpDef);    % pump
                %                                     %writePosition(valve, valveDef);        % valve
                %                                     writeDigitalPin (app.a1,'D13',0);          % red light off
                %                                     writeDigitalPin (app.a1,'D12',1);          % green light on
                %                                 elseif app.upFloat == 1
                %                                     % OFF UNTIL TESTABLE
                %                                     %writeDigitalPin (a2,'D11',1);  % increase pump speed
                %                                     %writePosition(valve, 0);       % close valve
                %                                     writeDigitalPin (app.a1,'D13',1);  % red light on
                %                                     writeDigitalPin (app.a1,'D12',0);  % green light off
                %                                 elseif app.lowFloat == 1
                %                                     % OFF UNTIL TESTABLE
                %                                     %writeDigitalPin (a2,'D11',0);  % stop pump
                %                                     %writePosition(valve, 1);       % incease valve drain speed
                %                                     writeDigitalPin (app.a1,'D13',1);  % red light on
                %                                     writeDigitalPin (app.a1,'D12',0);  % green light off
                %                                 end
                %                             else                        % MANUAL MODE
                %                                 if app.pumpSwitch == 1
                %                                     % OFF UNTIL TESTABLE
                %                                     %writeDigitalPin (a2,'D11',pumpSlider);
                %                                 else
                %                                     % OFF UNTIL TESTABLE
                %                                     %writeDigitalPin (a2,'D11',0);
                %                                 end
                %                                 if app.valveSwitch == 1
                %                                     % OFF UNTIL TESTABLE
                %                                     %writePosition(valve, valveSlider);
                %                                 else
                %                                     % OFF UNTIL TESTABLE
                %                                     %writePosition(valve, 0);
                %                                 end
                %                                 if app.servoSwitch == 1
                %                                     % OFF UNTIL TESTABLE
                %                                     %writePosition(valve, servoSlider);
                %                                 else
                %                                     % OFF UNTIL TESTABLE
                %                                     %writePosition(valve, 0);
                %                                 end
                %                                 if app.tempSwitch == 1
                %                                     % TEMPERATURE CALCULATIONS AND UPDATES
                %                                     app.therm = readVoltage(app.a1,'A1');                        % Get value from the digital pin an store it in digital                                                            % thermistor B parameter, in Kelvin
                %                                     current = app.therm/app.R2;                                 % calculate the current using Ohm's law
                %                                     Resistance = (5-app.therm)/current;                         % find the resistance of the thermistor
                %                                     recip_temp = 1/app.temp0 + log(Resistance/app.res0)/app.B;  % Calculate the reciprocal of the TempK
                %                                     TempK = 1./recip_temp;                                      % Calculate Temp in Kelvin
                %                                     TempF=((TempK -273.15)*1.8)+32;                             % Convert Kelvin to Fahrenheit
                %                                     app.TestLabel.Text = num2str(TempF,3);                      % Convert the value to a string and assign to the label.  Precision 3
                %                                 else
                %                                     % stop reading temperature data
                %                                 end
                %                                 if app.visionSwitch == 1
                %                                     % read vision system data
                %                                 else
                %                                     % stop reading vision system data
                %                                 end
                %                             end
                %                             app.currTime = datetime(now,'ConvertFrom','datenum');
                %                             if app.currTime >= app.dataTime
                %                                 % insert data collection here
                %                                 % insert chart updates here
                %                                 app.dataTime = app.dataTime + app.interval;
                %                             end
                %                         end
                %                     else
                %                         % insert invalid calendar date actions here
                %                     end
                %                 else
                %                     break;
                %                 end 
            end
        end

        % Callback function
        function UIFigureCloseRequest(app, event)
            delete(app)
        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 TabGroup2
            app.TabGroup2 = uitabgroup(app.UIFigure);
            app.TabGroup2.Position = [1 1 640 480];

            % Create MAINTab
            app.MAINTab = uitab(app.TabGroup2);
            app.MAINTab.Title = 'MAIN';

            % Create HYDROPONICSSYSTEMLabel
            app.HYDROPONICSSYSTEMLabel = uilabel(app.MAINTab);
            app.HYDROPONICSSYSTEMLabel.HorizontalAlignment = 'center';
            app.HYDROPONICSSYSTEMLabel.FontSize = 48;
            app.HYDROPONICSSYSTEMLabel.Position = [14 376 603 76];
            app.HYDROPONICSSYSTEMLabel.Text = 'HYDROPONICS SYSTEM';

            % Create ONOFFButton
            app.ONOFFButton = uibutton(app.MAINTab, 'state');
            app.ONOFFButton.ValueChangedFcn = createCallbackFcn(app, @ONOFFButtonValueChanged, true);
            app.ONOFFButton.Text = 'ON/OFF';
            app.ONOFFButton.Position = [29 216 588 49];

            % Create RunUntilDatePickerLabel
            app.RunUntilDatePickerLabel = uilabel(app.MAINTab);
            app.RunUntilDatePickerLabel.HorizontalAlignment = 'right';
            app.RunUntilDatePickerLabel.Position = [94 314 58 22];
            app.RunUntilDatePickerLabel.Text = 'Run Until:';

            % Create RunUntilDatePicker
            app.RunUntilDatePicker = uidatepicker(app.MAINTab);
            app.RunUntilDatePicker.Position = [167 314 150 22];
            app.RunUntilDatePicker.Value = datetime([2040 1 1]);

            % Create HoursEditFieldLabel
            app.HoursEditFieldLabel = uilabel(app.MAINTab);
            app.HoursEditFieldLabel.HorizontalAlignment = 'right';
            app.HoursEditFieldLabel.Position = [358 341 38 22];
            app.HoursEditFieldLabel.Text = 'Hours';

            % Create HoursEditField
            app.HoursEditField = uieditfield(app.MAINTab, 'numeric');
            app.HoursEditField.Position = [411 341 100 22];

            % Create MinutesEditField
            app.MinutesEditField = uieditfield(app.MAINTab, 'numeric');
            app.MinutesEditField.Position = [411 314 100 22];

            % Create MinutesEditFieldLabel
            app.MinutesEditFieldLabel = uilabel(app.MAINTab);
            app.MinutesEditFieldLabel.HorizontalAlignment = 'right';
            app.MinutesEditFieldLabel.Position = [349 314 47 22];
            app.MinutesEditFieldLabel.Text = 'Minutes';

            % Create SecondsEditField
            app.SecondsEditField = uieditfield(app.MAINTab, 'numeric');
            app.SecondsEditField.Position = [411 285 100 22];

            % Create SecondsEditFieldLabel
            app.SecondsEditFieldLabel = uilabel(app.MAINTab);
            app.SecondsEditFieldLabel.HorizontalAlignment = 'right';
            app.SecondsEditFieldLabel.Position = [344 285 52 22];
            app.SecondsEditFieldLabel.Text = 'Seconds';

            % Create TestLabel
            app.TestLabel = uilabel(app.MAINTab);
            app.TestLabel.FontSize = 24;
            app.TestLabel.Position = [405 105 50 29];
            app.TestLabel.Text = 'Test';

            % Create AutomaticManualSwitchLabel
            app.AutomaticManualSwitchLabel = uilabel(app.MAINTab);
            app.AutomaticManualSwitchLabel.HorizontalAlignment = 'center';
            app.AutomaticManualSwitchLabel.Position = [114 76 140 22];
            app.AutomaticManualSwitchLabel.Text = 'Automatic/Manual Switch';

            % Create AutomaticManualSwitch
            app.AutomaticManualSwitch = uiswitch(app.MAINTab, 'slider');
            app.AutomaticManualSwitch.Items = {'Automatic', 'Manual'};
            app.AutomaticManualSwitch.Position = [160 113 45 20];
            app.AutomaticManualSwitch.Value = 'Automatic';

            % Create MANUALTab
            app.MANUALTab = uitab(app.TabGroup2);
            app.MANUALTab.Title = 'MANUAL';

            % Create ValveFlowrateSliderLabel
            app.ValveFlowrateSliderLabel = uilabel(app.MANUALTab);
            app.ValveFlowrateSliderLabel.HorizontalAlignment = 'right';
            app.ValveFlowrateSliderLabel.Position = [206 263 52 28];
            app.ValveFlowrateSliderLabel.Text = {'Valve'; 'Flowrate'};

            % Create ValveFlowrateSlider
            app.ValveFlowrateSlider = uislider(app.MANUALTab);
            app.ValveFlowrateSlider.Orientation = 'vertical';
            app.ValveFlowrateSlider.Position = [279 278 3 150];

            % Create PumpSpeedSliderLabel
            app.PumpSpeedSliderLabel = uilabel(app.MANUALTab);
            app.PumpSpeedSliderLabel.HorizontalAlignment = 'right';
            app.PumpSpeedSliderLabel.Position = [8 263 40 28];
            app.PumpSpeedSliderLabel.Text = {'Pump'; 'Speed'};

            % Create PumpSpeedSlider
            app.PumpSpeedSlider = uislider(app.MANUALTab);
            app.PumpSpeedSlider.Orientation = 'vertical';
            app.PumpSpeedSlider.Position = [69 277 3 151];

            % Create ServoPositionSliderLabel
            app.ServoPositionSliderLabel = uilabel(app.MANUALTab);
            app.ServoPositionSliderLabel.HorizontalAlignment = 'right';
            app.ServoPositionSliderLabel.Position = [419 262 48 28];
            app.ServoPositionSliderLabel.Text = {'Servo'; 'Position'};

            % Create ServoPositionSlider
            app.ServoPositionSlider = uislider(app.MANUALTab);
            app.ServoPositionSlider.Orientation = 'vertical';
            app.ServoPositionSlider.Position = [488 277 3 151];

            % Create CurrentSpeedGaugeLabel
            app.CurrentSpeedGaugeLabel = uilabel(app.MANUALTab);
            app.CurrentSpeedGaugeLabel.HorizontalAlignment = 'center';
            app.CurrentSpeedGaugeLabel.Position = [162 256 46 28];
            app.CurrentSpeedGaugeLabel.Text = {'Current'; 'Speed'};

            % Create CurrentSpeedGauge
            app.CurrentSpeedGauge = uigauge(app.MANUALTab, 'linear');
            app.CurrentSpeedGauge.Orientation = 'vertical';
            app.CurrentSpeedGauge.Position = [124 263 40 172];

            % Create CurrentFlowrateGaugeLabel
            app.CurrentFlowrateGaugeLabel = uilabel(app.MANUALTab);
            app.CurrentFlowrateGaugeLabel.HorizontalAlignment = 'center';
            app.CurrentFlowrateGaugeLabel.Position = [367 256 52 28];
            app.CurrentFlowrateGaugeLabel.Text = {'Current'; 'Flowrate'};

            % Create CurrentFlowrateGauge
            app.CurrentFlowrateGauge = uigauge(app.MANUALTab, 'linear');
            app.CurrentFlowrateGauge.Orientation = 'vertical';
            app.CurrentFlowrateGauge.Position = [332 263 40 172];

            % Create CurrentPositionGaugeLabel
            app.CurrentPositionGaugeLabel = uilabel(app.MANUALTab);
            app.CurrentPositionGaugeLabel.HorizontalAlignment = 'center';
            app.CurrentPositionGaugeLabel.Position = [578 256 48 28];
            app.CurrentPositionGaugeLabel.Text = {'Current'; 'Position'};

            % Create CurrentPositionGauge
            app.CurrentPositionGauge = uigauge(app.MANUALTab, 'linear');
            app.CurrentPositionGauge.Orientation = 'vertical';
            app.CurrentPositionGauge.Position = [541 263 40 172];

            % Create PumpToggleButton
            app.PumpToggleButton = uibutton(app.MANUALTab, 'state');
            app.PumpToggleButton.Text = 'Pump Toggle';
            app.PumpToggleButton.Position = [9 200 186 40];

            % Create ValveToggleButton
            app.ValveToggleButton = uibutton(app.MANUALTab, 'state');
            app.ValveToggleButton.Text = 'Valve Toggle';
            app.ValveToggleButton.Position = [227 200 186 40];

            % Create ServoToggleButton
            app.ServoToggleButton = uibutton(app.MANUALTab, 'state');
            app.ServoToggleButton.Text = 'Servo Toggle';
            app.ServoToggleButton.Position = [441 200 186 40];

            % Create SetasdefaultpumpspeedButton
            app.SetasdefaultpumpspeedButton = uibutton(app.MANUALTab, 'push');
            app.SetasdefaultpumpspeedButton.Position = [10 150 186 39];
            app.SetasdefaultpumpspeedButton.Text = 'Set as default pump speed';

            % Create SetasdefaultvalveflowrateButton
            app.SetasdefaultvalveflowrateButton = uibutton(app.MANUALTab, 'push');
            app.SetasdefaultvalveflowrateButton.Position = [229 150 186 39];
            app.SetasdefaultvalveflowrateButton.Text = 'Set as default valve flowrate';

            % Create ResetdefaultvaluesButton
            app.ResetdefaultvaluesButton = uibutton(app.MANUALTab, 'push');
            app.ResetdefaultvaluesButton.Position = [10 94 406 40];
            app.ResetdefaultvaluesButton.Text = 'Reset default values';

            % Create NOTEADDPHSERVOCONTROLLabel
            app.NOTEADDPHSERVOCONTROLLabel = uilabel(app.MANUALTab);
            app.NOTEADDPHSERVOCONTROLLabel.Position = [429 105 198 22];
            app.NOTEADDPHSERVOCONTROLLabel.Text = 'NOTE: ADD PH SERVO CONTROL';

            % Create DATAHISTORYTab
            app.DATAHISTORYTab = uitab(app.TabGroup2);
            app.DATAHISTORYTab.Title = 'DATA HISTORY';

            % Create UIAxes
            app.UIAxes = uiaxes(app.DATAHISTORYTab);
            title(app.UIAxes, 'Title')
            xlabel(app.UIAxes, 'X')
            ylabel(app.UIAxes, 'Y')
            zlabel(app.UIAxes, 'Z')
            app.UIAxes.Position = [29 299 590 130];

            % Create UIAxes_2
            app.UIAxes_2 = uiaxes(app.DATAHISTORYTab);
            title(app.UIAxes_2, 'Title')
            xlabel(app.UIAxes_2, 'X')
            ylabel(app.UIAxes_2, 'Y')
            zlabel(app.UIAxes_2, 'Z')
            app.UIAxes_2.Position = [29 150 590 140];

            % Create UIAxes_3
            app.UIAxes_3 = uiaxes(app.DATAHISTORYTab);
            title(app.UIAxes_3, 'Title')
            xlabel(app.UIAxes_3, 'X')
            ylabel(app.UIAxes_3, 'Y')
            zlabel(app.UIAxes_3, 'Z')
            app.UIAxes_3.Position = [29 11 590 123];

            % Create DATASTATUSTab
            app.DATASTATUSTab = uitab(app.TabGroup2);
            app.DATASTATUSTab.Title = 'DATA STATUS';

            % Create UIAxes2
            app.UIAxes2 = uiaxes(app.DATASTATUSTab);
            title(app.UIAxes2, 'Live Camera Feed')
            xlabel(app.UIAxes2, 'X')
            ylabel(app.UIAxes2, 'Y')
            zlabel(app.UIAxes2, 'Z')
            app.UIAxes2.Position = [127 233 380 184];

            % Create VolumeGaugeLabel
            app.VolumeGaugeLabel = uilabel(app.DATASTATUSTab);
            app.VolumeGaugeLabel.HorizontalAlignment = 'center';
            app.VolumeGaugeLabel.Position = [572 84 46 22];
            app.VolumeGaugeLabel.Text = 'Volume';

            % Create VolumeGauge
            app.VolumeGauge = uigauge(app.DATASTATUSTab, 'linear');
            app.VolumeGauge.Orientation = 'vertical';
            app.VolumeGauge.Position = [528 87 40 242];

            % Create pHLabel
            app.pHLabel = uilabel(app.DATASTATUSTab);
            app.pHLabel.BackgroundColor = [1 1 1];
            app.pHLabel.HorizontalAlignment = 'center';
            app.pHLabel.FontSize = 48;
            app.pHLabel.Position = [266 88 107 115];
            app.pHLabel.Text = 'pH';

            % Create TempGauge_3Label
            app.TempGauge_3Label = uilabel(app.DATASTATUSTab);
            app.TempGauge_3Label.HorizontalAlignment = 'center';
            app.TempGauge_3Label.Position = [105 83 35 22];
            app.TempGauge_3Label.Text = 'Temp';

            % Create TempGauge_3
            app.TempGauge_3 = uigauge(app.DATASTATUSTab, 'linear');
            app.TempGauge_3.Orientation = 'vertical';
            app.TempGauge_3.Position = [56 86 40 242];

            % Create TempDataToggleButton
            app.TempDataToggleButton = uibutton(app.DATASTATUSTab, 'state');
            app.TempDataToggleButton.Text = 'Temp Data Toggle';
            app.TempDataToggleButton.Position = [9 38 150 46];

            % Create VolumeDataToggleButton
            app.VolumeDataToggleButton = uibutton(app.DATASTATUSTab, 'state');
            app.VolumeDataToggleButton.Text = 'Volume Data Toggle';
            app.VolumeDataToggleButton.Position = [475 39 151 46];

            % Create pHDataToggleButton
            app.pHDataToggleButton = uibutton(app.DATASTATUSTab, 'state');
            app.pHDataToggleButton.Text = 'pH Data Toggle';
            app.pHDataToggleButton.Position = [240 33 151 46];

            % 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 = HydroponicsDraft

            % Create UIFigure and 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

[Jevan Lewis]

bumping because I haven't received an answer yet

Answer 1

[Adam Danz]

At quick glance, it appears that when you press the on/off button the app enters a while-loop and there is no exit to the loop so it continually runs and you cannot interrupt it. Pressing the [x] button to close the app get queued and waits for the never-ending while-loop to end.

Without knowing more about what the on/off button callback function is supposed to be doing, I cannot recommend anything specific. But you could add a flag within the while-loop that can be used to stop the while loop. This idea is described in this answer.