GUI issue edit text boxes not empty when blank

I want to check if my edit-text fields in my GUI are blank, before checking if these values are valid for a given piece of equipment.

My code is:

function CheckValuesButton_Callback(hObject, eventdata, handles)

    if handles.NominalWeightRadio == 1
        NW = (handles.NominalWeightEdit);
        if isempty(NW)
            errordlg('Add Nominal Weight.','Error')
            return
        end
    end

    BOPType = char(handles.BOPTypeBox);
    RamDesign = char(handles.RamDesignBox);

    ID = (handles.InsideDiameterEdit);
    if isempty(ID)
        errordlg('Add Inside Diameter.','Error')
        return
    end

    OD = (handles.OutsideDiameterEdit);
    if isempty(OD)
        errordlg('Add Outside Diameter.','Error')
        return    
    end

    [MaxWall, MaxDiam] = getMaxDims(BOPType,RamDesign);

    handles.errorDims = checkDims(MaxWall, MaxDiam, ID, OD);
    guidata(hObject,handles)

The problem is that even though I have not touched the edit-text boxes, they are not empty, i.e., my code continues to run, and crashes in checkDims when there are no numerical values for ID and OD. When I print the handles i get:

handles = 
    OutsideDiameterEdit: [1x1 UIControl]
     InsideDiameterEdit: [1x1 UIControl]
    PipeDescriptionEdit: [1x1 UIControl]
      NominalWeightEdit: 15

Where I have inserted info for the NominalWeightEdit text box.

How can I get these to be empty, instead of [1x1 UIControl].

Thanks

Joakim

[Joakino]

Here is for example the code for my InsideDiameterEdit:

function InsideDiameterEdit_Callback(hObject, eventdata, handles)
  % hObject    handle to InsideDiameterEdit (see GCBO)
  % eventdata  reserved - to be defined in a future version of MATLAB
  % handles    structure with handles and user data (see GUIDATA)
  handles.InsideDiameterEdit = str2double(get(hObject,'String'));
  guidata(hObject, handles)
  % Hints: get(hObject,'String') returns contents of InsideDiameterEdit as text
  %        str2double(get(hObject,'String')) returns contents of InsideDiameterEdit as a double

Answer 1

[Ingrid]

you should use

ID = get(handles.InsideDiameterEdit,'String')

to check what the value is in the edit-field. It will be empty if you have not typed in anything. If you have typed in a value, you should use str2double() to convert it and also perform an errorcheck there (because the user might have typed in something else than a number by mistake)

[Joakino]

This works perfectly when I dont enter anything. However, if i try to enter a value in e.g. NominalWeight, with this code:

NW = get(handles.NominalWeightEdit,'String'); %THIS IS LINE 162
    if isempty(NW)
        errordlg('Add Nominal Weight.','Error')
        return
    end

I get the following error:

Error using handle.handle/get
Invalid or deleted object.

Error in Version4>CheckValuesButton_Callback (line 162)
    NW = get(handles.NominalWeightEdit,'String');

Error in gui_mainfcn (line 95)
        feval(varargin{:});

Error in Version4 (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)Version4('CheckValuesButton_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback

[Walter Roberson]

http://www.mathworks.com/help/matlab/ref/isgraphics.html