Call component callback from another function

Hello all,

I am in a situation where I need to call a component's callback from another function. This component (a file menu) and its callback are defined in another script as follows (I am not 100% if this is the most efficient way to define callbacks but it's the way I've been using):

% "file1.m"
% Create SaveMenu
app.GUI.Menus.menuSave = uimenu(app.GUI.Menus.menuFile);
app.GUI.Menus.menuSave.MenuSelectedFcn =  {@Save, app};
app.GUI.Menus.menuSave.Text = 'Save';

%...

function Save(~, ~, app)
% ... do something ...
end

I need to call the function named Save from another script (let's call it "file2.m"). Is there anyway I can refer to the component (app.GUI.Menus.menuSave) and execute its MenuSelectedFcn? I have tried a couple of different ways but none of them works...

Thank you.

Answer 1

[Goncalo Torres]

Found a solution for it.

Basically, using feval, I can pass the function callback as follows:

feval(app.GUI.Menus.menuSave.MenuSelectedFcn{1},...)

Answer 2

[Yongjian Feng]

A callback function in your case is just a method of a class. You called your class file1 apparently. The Save method doesn't depend on the file1 obj. So can be called by creating a temp file1 object, and then call the Save method of that file1 object.

The only thing you need to worry about is the last input argument (called app in your file). Not sure how app is used inside the Save method. You might need to find the correct app when you call Save.

[Goncalo Torres]

Hi Yongjian,

Thank you for your reply.

To give you a bit more context, this is from an application, intially developed from app designer. However, I do not like to keep the code in a single mlapp file, so I normally create external functions with functionality or with component declaration. In this case, file1.m is just a function file that creates the file menu of my application, and not an object.

In file1.m, I create my component (menuSave) and assign it the function @Save for when the menu is clicked. Therefore, @save is only a sub-function in the function file "file1.m", and I cannot call it directly.

However, I do have access to my component menuSave, which containts the handle to the function @Save. I just don't know how to execute it from there.

K>> app.GUI.Menus.menuSave.MenuSelectedFcn

ans =

  2×1 cell array

    {        @Save}  % this is the function handle to save
    {1×1 app}

[Yongjian Feng]

I see. Basically you define your Save function as local function of script file1.m.

You can't call a local function of a script outside of file1.m.

Since Save doesn't depend on anything else except the input arguments (basically it just needs app), it can be a global function.

Give it a better name (to decribe what it is). Something like SaveFileFromApp. Then put it in a file called SaveFileFromApp.m. Make sure it is accessible for both callers.