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GUI issue edit text boxes not empty when blank

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Joakino on 6 Jan 2016
Commented: Walter Roberson on 6 Jan 2016
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')
BOPType = char(handles.BOPTypeBox);
RamDesign = char(handles.RamDesignBox);
ID = (handles.InsideDiameterEdit);
if isempty(ID)
errordlg('Add Inside Diameter.','Error')
OD = (handles.OutsideDiameterEdit);
if isempty(OD)
errordlg('Add Outside Diameter.','Error')
[MaxWall, MaxDiam] = getMaxDims(BOPType,RamDesign);
handles.errorDims = checkDims(MaxWall, MaxDiam, ID, OD);
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].

  1 Comment

Joakino on 6 Jan 2016
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

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Answers (1)

Ingrid on 6 Jan 2016
Edited: Ingrid on 6 Jan 2016
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 on 6 Jan 2016
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')
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)
Error in Version4 (line 42)
gui_mainfcn(gui_State, varargin{:});
Error in>@(hObject,eventdata)Version4('CheckValuesButton_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback

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