How to use the variables created within the GUI button function in other functions? (How to call the handles structure?)

global lstBox;

inputfolder = uicontrol('Style','pushbutton','String','InputFolder', 'Position', [4 2 15 4.5], @inputfoler_callback);

lstBox = uicontrol('Style','listbox','Units','Normalized','Position', [0.06 0.03 0.9 0.95], @lstBox_callback);

function inputfolder_callback(hObject,eventdata,handles)

folderPath = uigetdir('','inputpath');

imgFiles = dir(fullfile(folderPath, '**\*.png'));

testRemove = contains({imgFiles.name},'test');

imgFiles(testRemove) = [];

imgNames = {imgFiles.name};

handles.imgFiles = imgFiles;

set(lstBox, 'String', []);

set(lstBox, 'String', imgNames);

set(lstBox, 'Value', 1);

guidata(hObject, handles);

end

function lstBox_callback(hObject,eventdata,handles)

files = handles.imgFiles;

path = files(1).folder + "\" + files(1).name;

end

This code attempts to load a png image file into the path selected with the Inputfolder button and write a code indicating the png file name in the lstBox.

Save the structure of the .png file in the 'imgFiles' variable

"testRemove" removes the value with the name "test" and saves only the file name in "imgNames".

And store the imgFiles in the 'handles' structure.

From the listBox_callback function, you are trying to open an image by retrieving the hands.imgFiles in the hands

The error message files = hands.imgFiles; Insufficient input arguments in this code.

So what I'm curious about in this code is

1. How to use variables saved in handles in other functions?

- Insufficient input arguments error

2. I'm trying to output a png file name to lstBox, how to call lstBox within a function without specifying the lstBox variable as global?

[Stephen23]

Avoid GLOBAL variables.

The answers to your questions are here:

https://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

and here:

https://www.mathworks.com/matlabcentral/answers/483657-how-to-create-a-gui