How to share variables between two nested functions?

I have a parent function, Mass_Spec_Formatter_Beta, which generates a GUI. The purpose of this GUI is to allow the user to select an Excel file and process that file using formatting choices they selectede from the GUI. In the main GUI function, there are two nested functions, a small one that runs when the 'File Selection' button is pushed (LoadDataFile), and the main one which runs when the 'Analyze Data' button is pushed (ProcessData). The purpose of the smaller function is to open a file selection window for the user and change the name of the button to reflect the name of the file chosen. The purpose of the second larger function is to proces the data.

The problem is this: I need the smaller function to export the variable 'Location' (which is the filepath for the selected excel file) to thew larger nested function so that it can read the file and process it. However, I can't get the small nested function to send its variables back to the main function. I've tried preallocating 'Location', but this doesn't help. Declaring it global also doesn't help.

I need the variable 'Location' which is created in the LoadDataFile function to be taken into the ProcessData function. Thanks!

     % Set up the button to select the data file
        FileButton = uibutton(rightgrid,'push','Text','No File Selected! Please Select a File.','Interruptible','off','ButtonPushedFcn',@(FileButton,event) LoadDataFile);
    function Location = LoadDataFile
            % Prompt the user to select the file
            [file,filepath] = uigetfile({'*.xlsx';'*.csv'},'File Selector','Please Select a Mass Spec Data File to Open');
            
            % If the file was not selected, end the program immediately
            if file == 0
                close all
                return
            end
            Location = append(filepath,file);   % Create a solid path to the data file
            FileButton.Text = append('Selected File: ',file);
            SettingButton.Enable = true;
            SettingButton.Text = 'Analyze Data with Current Parameters';
        end

        % Set up the button to run the code
        SettingButton = uibutton(rightgrid,'push','Text','Please Select a File to Continue','Interruptible','off','Enable','off','ButtonPushedFcn',@(SettingButton,event) ProcessData(box1,box2,box3,box4,box5,box6,FilterList,UIFig,SettingButton,Location));

        % In the event the user decides to exit from the program, prompt
        % them first
        UIFig.CloseRequestFcn = @(src,event)my_closereq(src);
        function my_closereq(UIFig)
            selection = uiconfirm(UIFig,'Close the Processor?',...
                'Confirmation');
        
            switch selection
                case 'OK'
                    delete(UIFig)
                case 'Cancel'
                    return
            end
        end


%% Run the processing function only once the button confirming processing specifications have been pushed
    function ProcessData(box1,box2,box3,box4,box5,box6,FilterList,UIFig,SettingButton,Location)

Answer 1

[David Hill]

If the functions are nested, then variables are carried over into all the nested functions and the variable names should turn green to indicate that they are available everywhere (similar to global variables). Make sure your all your end's are in the right place.

function GUI
Location=[];
    function nested1
      Location='myFile';
    end
    function nested2
      Location='newFile';
    end
end

[Erik Myers]

Turns out if I deleted the function inputs, then they all transfer over flawlessly! Thanks for the super quick help Dave.

        FileButton = uibutton(rightgrid,'push','Text','No File Selected! Please Select a File.','Interruptible','off','ButtonPushedFcn',@(FileButton,event) LoadDataFile);
    function LoadDataFile
            % Prompt the user to select the file
            [file,filepath] = uigetfile({'*.xlsx';'*.csv'},'File Selector','Please Select a Mass Spec Data File to Open');
            
            % If the file was not selected, end the program immediately
            if file == 0
                close all
                return
            end
            Location = append(filepath,file);   % Create a solid path to the data file
            FileButton.Text = append('Selected File: ',file);
            SettingButton.Enable = true;
            SettingButton.Text = 'Analyze Data with Current Parameters';
        end

        % Set up the button to run the code
        %SettingButton = uibutton(rightgrid,'push','Text','Please Select a File to Continue','Interruptible','off','Enable','off','ButtonPushedFcn',@(SettingButton,event) ProcessData(box1,box2,box3,box4,box5,box6,FilterList,UIFig,SettingButton,Location));
        SettingButton = uibutton(rightgrid,'push','Text','Please Select a File to Continue','Interruptible','off','Enable','off','ButtonPushedFcn',@(SettingButton,event) ProcessData);

        % In the event the user decides to exit from the program, prompt
        % them first
        UIFig.CloseRequestFcn = @(src,event)my_closereq(src);
        function my_closereq(UIFig)
            selection = uiconfirm(UIFig,'Close the Processor?',...
                'Confirmation');
        
            switch selection
                case 'OK'
                    delete(UIFig)
                case 'Cancel'
                    return
            end
        end


%% Run the processing function only once the button confirming processing specifications have been pushed
    function ProcessData