update box with TextAeaValuechanged callback don't run

hi, when i change text in this area nothing happens

Am I doing something wrong or should I select Add ValueChangingFcn callback?

Answer 1

[Cris LaPierre]

It looks like you have already defined a callback function for when the value of the text area is changed. Have you added any code to it? Without seeng the code in the callback function, as well as knowing what it is you expect to happen, it's really difficult to provide specific feedback.

See the Adding callbacks in App Designer page for more details.

[Luca Re]

see that example

i load file in a folder but the callback don't run

i don't see 'i'm here' in my example

[Cris LaPierre]

It's doing exactly what you've programmed it to do. fprintf writes to the command window, not the text area.

[Luca Re]

yes this i know but in my commando area i don't see anything

[Cris LaPierre]

Hm. It works in R2023a. What version of MATLAB are you using?

[Luca Re]

>> version

ans =

'9.14.0.2254940 (R2023a) Update 2'

[Cris LaPierre]

I made no changes to your app. Here is a gif in R2023a in Windows 11.

[Luca Re]

I don't understand why it doesn't work for me...I use window10 though

[Cris LaPierre]

Are you using the exact same script you attached to this thread?

[Luca Re]

i have seen it update me after i move the cursor from the box to another part of the app.

Shouldn't it invoke the callback when I type into it?

[Cris LaPierre]

No. The 'valueChanged' callback will not execute until you are done, interpretted as changing focus away from the TextArea.

If you want your callback to execute as you are making changes, you need to use the 'valueChangingFcn' callback instead.

[Luca Re]

in my example the box was non-editable and I changed it via code (by pressing the button) Then moving to another part of the gui he didn't write to me

[Cris LaPierre]

When you change the text programmatically, the callback function is not run.

[Luca Re]

ok thanks then problem solved

[Cris LaPierre]

If you want the callback to execute when you are changing the value programmatically, you just need to call that function inside the callback function that is executing.

% Button pushed function: Button
function ButtonPushed(app, event)
    [file,path] = uiputfile ({'*.*'}, 'Select a file');
    [~,name,~] = fileparts(file);
    app.TextArea.Value=name;
    TextAreaValueChanged(app, app.TextArea)
end

[Luca Re]

yes, in fact I have already done this