MATLAB: I want to evaluate this textbox for validation. but i got this error.

errortext;validation

Error

Undefined variable "handles" or class "handles.t1".
Error in DESIGN>b1_Callback (line 292)
 x=get(handles.t1,'string');
Error while evaluating UIControl Callback

For this code

f=figure;
t1= uicontrol(f,'Style','edit','String','','Position',[180 580 130 20]);
b1 = uicontrol(f,'Style','pushbutton','String','GENERATE','Position',[100 365 100 40],'Callback',@b1_Callback);
function b1_Callback(source,eventdata)
 x=get(handles.t1,'string');
  if(isempty(x))
     msgbox('enter the text');
 else
     msgbox('ds');
 end

Please solve this error

Best Answer

handles is not automatically passed by MATLAB. When you create a callback using GUIDE then GUIDE arranges for the callback to be passed but when you create your own callback then you have to pass it yourself if you want it. (You also have to create the handles structure yourself)

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You're reassigning handles.edit_box1 which loses your handle. Instead, use

x=str2double(get(handles.edit_box1,'String'));
setappdata(handles.figure1,'x',x);

and

y=str2double(get(handles.edit_box2,'String'));
setappdata(handles.figure1,'y',y);

in both the edit boxes, then in the pushbutton function use

x = getappdata(handles.figure1, 'x');
y = getappdata(handles.figure1, 'y');
c = 2*(x + y);

MATLAB: Grapg is not activate plz help me

function mornig
A = 0; F = 0; T = 0;     %not global!
N=500;
M=300;
handles.fig=figure;
mpos = get(handles.fig,'position');
set(handles.fig, 'position',[mpos(3) mpos(4) N M]);
handles.axes = axes();
set(handles.fig,'unit','pixels');
set(handles.axes,'unit','pixels');
handles.edit1 = uicontrol('style','edit');
set(handles.edit1,'position',[N-360 0 120 20]);
set(handles.edit1,'string','A');
set(handles.edit1,'horizontalalignment','center');
handles.edit2 = uicontrol('style','edit');
set(handles.edit2,'position',[N-240 0 120 20]);
set(handles.edit2,'string','F');
set(handles.edit2,'horizontalalignment','center');
handles.edit3 = uicontrol('style','edit');
set(handles.edit3,'position',[N-120 0 120 20]);
set(handles.edit3,'string','T');
set(handles.edit3,'horizontalalignment','center');
set(handles.edit1, 'callback', @edit_callback1);
set(handles.edit2, 'callback', @edit_callback2);
set(handles.edit3, 'callback', @edit_callback3);
%now nested functions
function edit_callback1(src, event_data)
  A = str2double( get(src, 'String') );
end
function edit_callback2(src, event_data)
  F = str2double( get(src, 'String') );
end
function edit_callback3(src, event_data)
  T = str2num( get(src, 'String') );    %because it probably is not a scalar
    plot(handles.axes, T, A*cos(2*pi*F*T));
  end

Note that in order for you to see much, you will need to enter a vector of values for T

Best Answer

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MATLAB: Trying to make a simple calculator/multiplyer. Only works for the first time.

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