Vector Input, GUI edit text box

Hi,

I am trying to get a vector input from the user in a GUI using edit text boxe, but it seems that the program doesn't recognize the text boxes, although I have them in my GUI. Can someone tell what is the problem?

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
Xn=str2num(get(handle.edit1,'string'));
Yn=str2num(get(handle.edit2,'string'));
dn=str2num(get(handle.edit3,'String'));

The class handle has no Constant property or Static method named 'edit1'.

[Sriram Tadavarty]

Hi Daniel,

Replace the variable 'handle' with 'handles' while calculating Xn, Yn and Dn. This should solve.

Regards,

Sriram

[Daniel Liberman]

Thank You,

Now Im having another problem.

I used asingin function to see what is the input I get for Xn, Yn, Dn.

My inputs are: for Xn-0,1.5,0,5,6.5,10 , for Yn-0,0,1.5,4,4,6 , for dn-1,1,1,1,1,1, but what I get is:

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
Xn=str2double(get(handles.edit1,'String'));
assignin('base','Xn',Xn);
Yn=str2double(get(handles.edit2,'String'));
assignin('base','Yn',Yn);
dn=str2double(get(handles.edit3,'String'));
assignin('base','dn',dn);

[Geoff Hayes]

Daniel - is there a reason that you are assigning these varaibles to the base workspace? Why not just add them as fields to the handles structure so that other callbacks in your app can access them?

[Geoff Hayes]

Also, try using str2num instead of str2double since the former should preserve the array:

>> x = '-0,1.5,0,5,6.5,10';
>> str2num(x)

ans =

         0    1.5000         0    5.0000    6.5000   10.0000
>> str2double(x)

ans =

   NaN

[Adam Danz]

Another way to convert the values without using str2num (which uses eval and can lead to undexpected behaviors) is,

x = '-0,1.5,0,5,6.5,10';
d = str2double(strsplit(x, ','))

or, depending on how the values are delimited,

x = '-0 1.5 0 5 6.5 10';
d = str2double(strsplit(x))

[Daniel Liberman]

Geoff Hayes, I tryed using str2num and it returns me the following error: "Error using str2num (line 31)

Requires character vector or array input."

Adam Danz, the input is something the user should type to the edit texts in the GUI, not directly to the code.

[Adam Danz]

"the input is something the user should type to the edit texts in the GUI, not directly to the code."

Yeah, I'm aware of that. The x values in my comment were for demonstration purposes. They should be similar to the values you get from

x = handle.edit1.string;
% or
x = get(handle.edit1,'string')

If you get an error, we'll need to see what the input looks like.

Note that this method allows the user to enter anything including typos, brackets, and other symbols that won't be interpretted correctly. You could use a try/catch to prompt the user to try again if they didn't enter a proper input.

[Daniel Liberman]

Now I'm getting the following error:

"Error using strsplit (line 80)

First input must be either a character vector or a string scalar."

[Adam Danz]

Please show us the input.

[Daniel Liberman]

thit is how the input looks like

[Daniel Liberman]

this*

[Daniel Liberman]

No brackets, just commas

Answer 1

[Adam Danz]

The string from a edit box is returned as a cell array of characters. If the expected inputs are a comma separated vector such as "1, 2, 3.14, 5", here's how to exact those values.

s = handles.edit1.String; 
d = str2double(strsplit(s{:}, ','));

I suggest using conditional error detection in order to provide the user with feedback in case they use an incompatible format.

s = handles.edit1.String; 
try
    d = str2double(strsplit(s{:}, ','));
catch 
    error('Edit field must contain comma separated values such as "6, 5, 3.14"')
end

[Daniel Liberman]

Thank you, It works :)

[Adam Danz]

The string value extracted from the edit box is actually a cell array of characters. So, if the user enters "1,1,2,4" the string output will be {'1,1,2,4'}. The {:} part of my answer solves that by returning the character array within the cell array.