Using animatedline in Matlab App Designer?

Hey everyone,

I am attempting to make a matlab app that is able to plot live data from my serial port. The data comes in separated with commas and is parsed accordingly (still in its early stages). I was able to get this code to work in the normal matlab code envirnment, shown below:

clear all;
delete(instrfindall);
clear;
close all;
clc;

s = serial('COM11', 'BaudRate',115200);
fopen(s);

voltage = 0;

t = 0;

y = 1;

data = fscanf(s);
data = convertCharsToStrings(data);
data = strsplit(data, ',');

TIME(y,1) = str2double(data(1));
VAR1(y,1) = str2double(data(2));
VAR2(y,1) = str2double(data(3));

h = animatedline(TIME(y,1),VAR1(y,1));
h2 = animatedline(TIME(y,1),VAR2(y,1));


xlim([TIME(y,1) TIME(y,1)+20]);
ylim([-1.2 1.2]);
grid on
title("Some Sine Waves");
xlabel("Time [sec]");
ylabel("Value");


tic
while t <= 200
    y= y+1;
    data = fscanf(s);
    data = convertCharsToStrings(data);
    data = strsplit(data, ',');

    TIME(y,1) = str2double(data(1));
    VAR1(y,1) = str2double(data(2));
    VAR2(y,1) = str2double(data(3));
    
    addpoints(h, TIME(y,1), VAR1(y,1));
    addpoints(h2, TIME(y,1), VAR2(y,1));

    
    xlim([TIME(y,1)-20 TIME(y,1)+4])
    
    %y= y+1;
    t=t+0.05;
    drawnow
end
toc

fclose(s);
delete(s);
clear s;

This code works and will plot the data. I tried some other methods and the matlab program started to lag very badly, especially after running for 20+ seconds.

Using this code, I tried to apply it to the Matlab App Designer and this is where I am having trouble. The code "error" I am getting below is...

Reference to non-existent field 'UIAxes'

which makes no sense because that is my figure title. This happens right as I define the "animatedline" function. I know other people are having similar problems. When I push a button, the code gets executed. The code in my matlab app designer code window is below:

classdef app1 < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        Apollo  matlab.ui.Figure
        Button  matlab.ui.control.Button
        UIAxis  matlab.ui.control.UIAxes
    end

    methods (Access = private)

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

        % Button pushed function: Button
        function ButtonPushed(app, event)
clear all;
delete(instrfindall);
clear;
close all;
clc;

s = serial('COM11', 'BaudRate',115200);
fopen(s);

t = 0;

y = 1;

data = fscanf(s);
data = convertCharsToStrings(data);
data = strsplit(data, ',');

app.TIME(y,1) = str2double(data(1));
app.VAR1(y,1) = str2double(data(2));
app.VAR2(y,1) = str2double(data(3));

app.h = animatedline(app.UIAxis, app.TIME(y,1),app.VAR1(y,1));
app.h2 = animatedline(app.UIAxis, app.TIME(y,1),app.VAR2(y,1));


% xlim([TIME(y,1) TIME(y,1)+20]);
% ylim([-1.2 1.2]);
% grid on
% title("Some Sine Waves");
% xlabel("Time [sec]");
% ylabel("Value");


tic
while t <= 200
    y= y+1;
    data = fscanf(s);
    data = convertCharsToStrings(data);
    data = strsplit(data, ',');

    TIME(y,1) = str2double(data(1));
    VAR1(y,1) = str2double(data(2));
    VAR2(y,1) = str2double(data(3));
    
    addpoints(h, TIME(y,1), VAR1(y,1));
    addpoints(h2, TIME(y,1), VAR2(y,1));

    
    %xlim([TIME(y,1)-20 TIME(y,1)+4])
    
    %y= y+1;
    t=t+0.05;
    drawnow
end
toc

fclose(s);
delete(s);
clear s;
        end
    end

    % App initialization and construction
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

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

            % Create Button
            app.Button = uibutton(app.Apollo, 'push');
            app.Button.ButtonPushedFcn = createCallbackFcn(app, @ButtonPushed, true);
            app.Button.Position = [45 428 100 22];

            % Create UIAxis
            app.UIAxis = uiaxes(app.Apollo);
            title(app.UIAxis, 'SINE WAVE')
            xlabel(app.UIAxis, 'X')
            ylabel(app.UIAxis, 'Y')
            app.UIAxis.PlotBoxAspectRatio = [1 0.571428571428571 0.571428571428571];
            app.UIAxis.Position = [83 111 407 261];
        end
    end

    methods (Access = public)

        % Construct app
        function app = app1

            % Create and configure components
            createComponents(app)

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

            % 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.Apollo)
        end
    end
end

[Ashleigh Reid]

Hi there,

Do you still have the arduino code for this task? I'm interested in how you read the data in. Many thanks.

Answer 1

[Chris Portal]

Your callback is doing a “clear all”, which clears out all of the variables available at that point, which in this case are “app” and “event”. That’s why when you try to access “app.UIAxis” you get an error saying it doesn’t exist.

I don’t see why you would need to call clear in your callback function. It looks like you may have copied this from a script, where the call to clear was serving more of a purpose.

Hope this helps!