How to use 'Edit Text' efficiently in a GUI?

I notices that there are two ways to ues it;

The tag of edit1 is edit1.

Method 1:

function edit1_callback()

         num1 = get(hObject,'string');
         handles.num1 = num1;
         guidatda(gcbo,handles);  % why need this command?

function pshbtn1_callback()

         y = handles.num1;
         guidata(gcbo,handles);  % why need it too?

Method 2:

function pshbtn_callback()

         y = str2num(get(hObject,handles));

As shown above, what's the difference? And the effect of "guidata(gcbo,handles)" ? Thank you very much!

[Lisa Wu]

The Method 2 should be:

 y = str2num(get(handles.edit1,'string'));

[siddharth]

the second method works just fine. Thanks

Answer 1

[Arthur]

If you use guidata(gcbo,handles), you save the string of your textbox in the 'handles' structure; in your pshbtn_callback you subsequently read this value from handles again. I personally prefer method 2, where you read out the string of the textbox in the button callback. This has a few advantages:

• you only use the handles structure for what it's supppost to (storing handles)
• you retrieve the string at the very moment you need it (ensures that you have the string that is actually shown in the textbox)

Method 1 is not wrong though, it will work.

[Lisa Wu]

Thank you very much!