MATLAB: How to avoid multiple file load in GUI

Question

I am doing a GUI and I am loading a .mat file with the data i need. So I call the file with load('file.mat') in the openingFcn. But when I want to use the data in another function like a callback button it does not find the variables and i have to load the file again in each function.

is there a specific place where I should load the file so it becomes global?

Answer 1

Every function (including callback functions) has its own workspace. Each workspace has its own variables: this is a good thing! Many beginners want all variables to exist in every workspace, but this is not a good way to manage data.

You can easily pass variables between workspaces:

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

http://www.mathworks.com/help/matlab/matlab_prog/share-data-between-workspaces.html

Writing nested functions is probably the easiest way to pass data between callback functions. Otherwise guidata is a good method to pick.

If you are passing data between functions that are not callbacks, passing arguments is the simplest, fastest, and most reliable.