MATLAB: Blank GUI figure handle? (noob question)

Question

sorry for this noob question, i just started to learn about GUI making, but i cannot figure out this:

when i create a new blank GUI using GUIDE, an .m file is generated. i cannot find inside this .m file the handle of the blank figure. callback functions of all gui elements (e.g. push buttons) are pointing to the same handles "hObject".

 so what is the handle of the blank figure, and what are the handles of added gui elements?

Answer 1

Although it might look confusing, the situation is clear and surely will become clear to you soon. You can create a button programatically or by guide. Both are equivalent, when you write:

handles.myButton1 = uicontrol('Style', 'PushButton', 'Tag', 'myButton1', ...
'Callback', @myButton1Callback);

Now the callback of the button is called as:

function myButton1Callback(hObject, EventData)

And inside this function you can obtain the current version of the handles struct easily:

handles = guidata(hObject);

GUIDE appends the handles struct as 3rd input automatically already, such that you get:

function myButton1Callback(hObject, EventData, handles)

But I'm not sure, if this handles struct is the newest version already (I'm not working with GUIDE), but the guidata method shown above will work also.

Each object in a GUI has its own handles, which can be seen as a pointer or address of the GUI object. In all callbacks, the handle of the activated object is called "hObject", but you can modify the name of the variable freely:

function myButton1Callback(ButtonHandle, EventData)
set(ButtonHandle, 'String', 'I am pressed');