function in app give "undefined function for input arguments"

Sample of one of the functions in my code. I made functions for my 2 other apps and they worked fine once I included the correct inputs but I cannot get the correct inputs other than "app" for this code and it gives me a different error than I have seen. Code below:

function PostTestAONButton(app)
            if app.MeasurementRangeAONButton.Value == 1
                file = dir(fullfile(directory,'*POST-TEST*AON_.txt'));

                for i = 1:numel(file)
                    filepath = fullfile(file(i).folder, file(i).name);

                    data_in = readmatrix(filepath);

                    % Grabbing only the frequency and SE values
                    x = data_in(:,1);
                    y = data_in(:,3);

                    % Plotting data based on various options selected
                    if app.IncludeonLegendCheckBoxAON.Value == 1
                        if app.MRMarkersButton.Value == 1
                            plot(x,y,"Color",app.MRColorDropDown.Value,'LineWidth',str2double(app.LineWidthDropDown.Value), ...
                                Marker=app.MRMarkerDropDown.Value,DisplayName='MR');
                        else
                            plot(x,y,"Color",app.MRColorDropDown.Value,'LineWidth',str2double(app.LineWidthDropDown.Value), ...
                                DisplayName='MR');
                        end
                    else
                        if app.MRMarkersButton.Value == 1
                            plot(x,y,'HandleVisibility','off',"Color",app.MRColorDropDown.Value,'LineWidth',str2double(app.LineWidthDropDown.Value), ...
                                Marker=app.MRMarkerDropDown.Value);
                        else
                            plot(x,y,'HandleVisibility','off',"Color",app.MRColorDropDown.Value,'LineWidth',str2double(app.LineWidthDropDown.Value));
                        end
                    end
                end
            else
            end
        end

[Walter Roberson]

                file = dir(fullfile(directory,'*POST-TEST*AON_.txt'));

should that be app.directory ?

[Tyler]

I didn't need to make it app.directory on my other code and that line is the same in both the others (similar codes for different applications)

[Walter Roberson]

You have not defined "directory" in that function. Are you expecting that "directory" is a function that is being called without any parameters, and which will return an appropriate directory name? If not then where are you expecting that it will locate a variable named directory? Is the function you posted a nested function with directory being a shared variable?

[Tyler]

Here is the start of the code.

if app.SingleFolderButton.Value == 1
    % Enter the directory to search
    directory = uigetdir('*',"Select Folder With Files To Be Processed");
    
    % List all items in the folder
    fileList = dir(directory);
    
    % Delete the subfolders from the list (i.e. only keep files)
    fileList(vertcat(fileList.isdir)) = [];
    
    % Set lamp color to yellow for in progress
    app.Lamp.Color = 'Yellow';
    
    % Uses folder as title of plot
    [ParentFolderPath] = fullfile(directory);
    [~, ParentFolderName] = fileparts(ParentFolderPath);
    
    % Loop through each file, copy it and give new extension: .txt
    for i = 1:numel(fileList)
        file = fullfile(directory, fileList(i).name);
        [tempDir, tempFile] = fileparts(file);
        status = copyfile(file, fullfile(tempDir, [tempFile, '.txt']));
    end  

    figure
    hold all

    PostTestAONButton(app);

[Walter Roberson]

You are expecting that, if necessary, a variable will be resolved to the workspace of the caller of the function.

In matlab the only time that kind of resolution of variables happens is if you define the function being called as a nested function, and the variable is assigned to in the nesting function before the definition of the nested function.

function outer
   A = 5;
   function C = inner
      C = A + B;
   end
   B = 11;
   inner()
 end

Variable A is properly nested and is available to inner but variable B is not defined at the point that inner is defined, so it would not be found, and the addition would fail (unless matlab could find a function named B)

[Voss]

@Walter Roberson: "before the definition of the nested function" I believe should be, "before the execution of the nested function"

outer % works

ans = 16

outer2 % fails

Unrecognized function or variable 'B'.

Error in solution>outer2/inner (line 16)
C = A + B;

Error in solution>outer2 (line 14)
inner() % fails because B is not defined yet

function outer
   A = 5;
   function C = inner % defining inner() here is ok, as long as B is defined before inner() is called
      C = A + B;
   end
   B = 11;            % B defined after the definition of inner() but before the execution of inner() works
   inner()
end


function outer2
   A = 5;
   inner()            % fails because B is not defined yet
   function C = inner
      C = A + B;
   end
   B = 11;
end

[Walter Roberson]

@Voss

Interesting, my memory had always been that the variable had to be defined before the nested function definition. Either that changed or my memory blipped again. Either of those are real possibilities ;-)