How to access app designer variables in the script file

I have created a gui on app designer. In this I am taking input from .csv file which is user input and i want to use this input in my script files. I have tried assign value and making variable global but it doesn't work.

please help.

Answer 1

[Adam Danz]

Don't use assigning() or eval(). That opens a can of worms. Here are two alternatives. Each method includes a demo but you'll have to replace the app name and component handle names.

If your data is already stored in an app component

If the data you loaded is already stored in an app component such as a UITable, you can simply using the app handle to get the handle to the UITable and retreive the data. Here's a demo.

% When you open your app, use the output to get the app handle
appHand = myFakeApp;         % This opens your app (insert your app name)
myData = appHand.UITable.Data; 

If your data is not already stored in any app components

Use

setappdata(obj,name,val)

to store the data to your UIFigure and

val = getappdata(obj,name)

to retreive it. Here's a demo where I store a variable named myData to the app figure.

app.UIFigure = uifigure();               % Use your app figure handle instead of creating a figure
setappdata(app.UIFigure,'myData',1:5);   % store myData to your app figure     

Now you can retreive it from any callback function or from the command window

% When you open your app, use the output to get the app handle
appHand = myFakeApp;                            % This opens your app (insert your app name)
myData = getappdata(appHand.UIFigure,'myData')  % Get the data stored in your app figure

[Ishita Kaul]

Thank you for your reply!

But I am facing still facing the issue that i m getting [ ] (blank) value for my variable in the .m script. Though i m passing some numerical value in the app designer code.

[Adam Danz]

Could you share the section of code that extracts the data from your app?

[Ishita Kaul]

Thanks for your help! I figured it out. I just passed app as a parameter and converted my .m script files to functions and that solved it! Now I can access the variables in my script files.

[Adam Danz]

I see. It would be better practice to pass the data directly from your app into the function rather than passing the app handle into the function. Either way you must extract the data from the app.

One reason why it's better to pass the data rather than passing the app handle is that your function becomes usless outside of that exact app. If you're passing the data as inputs, the function becomes much more versatile.

A second reason is that you don't want many files to have access to your app components. Changes to the app should only happen within the main app file, with few exceptions.

Lastly, it's much easier to read if you extract all of the needed data into a structure variable or cell array or some other container and then pass that to your external function.