Using the code you provided above:
IP_Adress_Phone=uicontrol('Style','edit','BackgroundColor','white',...
'Units','Normalized','Position',[.1 .1 .4 .1],...
'String','Enter your phone IP address here',...
'Visible','on','Callback',@callbackfn);
In order to extract data, you need to define the callback. The callback's first parameter will be a reference to the IP Text Field itself. You can then extract the Text Field's "String" Property.
function callbackfn(hObj, e)
ipAddr = hObj.String;
disp(['ipAddr: ' ipAddr]);
end
Callback's Documentation for reference:
