How to evaluate calback function in edit text uicontrol?

I have just started to learn about low-level GUI programing.

Is this the right way to write code. I need my variable b to change every time i hit new entry into edit text but I'm not geting that.

Am I missing evaluate function somewhere?

This is a simple example

fig_h=figure;

callb=['b=get(a,''string'')']

a=uicontrol(fig_h,'Position',[ .5 .5 .08 .06],'Style','edit','CallBack','callb','String','0','Units','normalized');

Thanks

Answer 1

[Matt Fig]

Please do not program callback using strings. Use function handles instead. Save this in an M-file then run the file to see how it works.

function [] = my_gui()
fig_h=figure;
a = uicontrol(fig_h, 'Style','edit',...
             'Units','normalized',...
             'Position',[.5 .5 .08 .06],... 
             'CallBack',@callb,...
             'String','0');

function [] = callb(H,E)
a = get(H,'string');
disp(['The string in the editbox is: ',a])

Here is a tutorial that starts basic and builds up to more advanced GUIS. I encourage you to work through it.

Answer 2

[Walter Roberson]

Callbacks that are given as strings are executed in the context of the base workspace, so look for b there.

See also: http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F

Answer 3

[Imo]

Thanks, I will try that. I guess no one likes the string approach maybe because it is really hard to read. I'm going to study function build. Thanks for the tip and new materials, I appreciate.