Multiple App Designer Compiler

I have designed an application with App Designer. It consists of 3 or 4 mlapp files, different matrices and tamblas to obtain data and some function. When I compile the application in a desktop app, the attempt to open the different windows works correctly for me, but when in theory I would have to save some values in the amtriz they don't. What is this about? Do I have to create a realtion for the application to find and save in the folder?

Answer 1

[Riya]

Hi Alejandro,

I understand that you have developed a desktop application using multiple “.mlapp” files that interact with each other to process and store data in matrices. While the windows open correctly after compilation, it seems the application fails to save values into the matrices as expected. This behavior is indeed common when working with multiple apps in compiled form.

This issue stems from how data is being shared across your different “.mlapp” files. When running inside MATLAB, variables can sometimes be accessed more freely. However, in a compiled app, each app instance runs in isolation, and hence does not share variables or workspace data unless this is explicitly handled.

To resolve this, use “.mat” files for data sharing. To enable reliable data sharing between app windows, consider saving and loading shared data (e.g., matrices) using “.mat” files stored in a valid directory. Here is an example approach:

In App 1 – Saving Data:

dataMatrix = [1 2 3; 4 5 6]; 
save(fullfile(tempdir, 'sharedData.mat'), 'dataMatrix'); 

In App 2 – Loading Data:

if isfile(fullfile(tempdir, 'sharedData.mat')) 
    loaded = load(fullfile(tempdir, 'sharedData.mat')); 
    dataMatrix = loaded.dataMatrix; 
end 

Note that using “tempdir” ensures that the path is writable even in compiled mode.

For further reference on file operations and data management in compiled applications, you may refer to the following official documentation:

https://www.mathworks.com/help/compiler/