how can I get the selected value of radio button?

Question

I am not matlab programmer but I need to create an interface using matlab! This qusetion should be very easy for matlab programmers :)

I have an interface which contains radio button group panel "OperationPanel" ,4 radioButtons inside it which names are "addBtn, subBtn, divBtn, mulBtn" and I have command button, I want when I click over the button to get the value of the selected radioButton

What is the commad I should use ? I google it and found that if I make

get(handles.NewValue,'Tag');

I tired it but it doesn't work!! Can I hava some help!

Answer 1

Here's a quick example to illustrate how to get the value of a radio-button group component:

function simpleGUI
    hFig = figure('Visible','off', 'Menu','none', 'Name','Calculator', 'Resize','off', 'Position',[100 100 350 200]);
    movegui(hFig,'center')          %# Move the GUI to the center of the screen

    hBtnGrp = uibuttongroup('Position',[0 0 0.3 1], 'Units','Normalized');
    uicontrol('Style','Radio', 'Parent',hBtnGrp, 'HandleVisibility','off', 'Position',[15 150 70 30], 'String','Add', 'Tag','+')
    uicontrol('Style','Radio', 'Parent',hBtnGrp, 'HandleVisibility','off', 'Position',[15 120 70 30], 'String','Subtract', 'Tag','-')
    uicontrol('Style','Radio', 'Parent',hBtnGrp, 'HandleVisibility','off', 'Position',[15  90 70 30], 'String','Multiply', 'Tag','*')
    uicontrol('Style','Radio', 'Parent',hBtnGrp, 'HandleVisibility','off', 'Position',[15  60 70 30], 'String','Divide', 'Tag','/')

    uicontrol('Style','pushbutton', 'String','Compute', 'Position',[200 50 60 25], 'Callback',{@button_callback})

    hEdit1 = uicontrol('Style','edit', 'Position',[150 150 60 20], 'String','10');
    hEdit2 = uicontrol('Style','edit', 'Position',[250 150 60 20], 'String','20');
    hEdit3 = uicontrol('Style','edit', 'Position',[200  80 60 20], 'String','');

    set(hFig, 'Visible','on')        %# Make the GUI visible

    %# callback function
    function button_callback(src,ev)
        v1 = str2double(get(hEdit1, 'String'));
        v2 = str2double(get(hEdit2, 'String'));
        switch get(get(hBtnGrp,'SelectedObject'),'Tag')
            case '+',  res = v1 + v2;
            case '-',  res = v1 - v2;
            case '*',  res = v1 * v2;
            case '/',  res = v1 / v2;
            otherwise, res = '';
        end
        set(hEdit3, 'String',res)
    end
end

Obviously you could add more validations on the input numbers and so on...

Answer 2

Have you set handles to the hOjbect? Also don't forget to update the handle after processing the radio button event. Have you looked at this Matlab GUI Tutorial? Scroll down to Part 3 step 5 to see the following example code for three radio buttons:

function fontSelect_buttongroup_SelectionChangeFcn(hObject, eventdata)

%retrieve GUI data, i.e. the handles structure
handles = guidata(hObject); 

switch get(eventdata.NewValue,'Tag')   % Get Tag of selected object
    case 'fontsize08_radiobutton'
      %execute this code when fontsize08_radiobutton is selected
      set(handles.display_staticText,'FontSize',8);

    case 'fontsize12_radiobutton'
      %execute this code when fontsize12_radiobutton is selected
      set(handles.display_staticText,'FontSize',12);

    case 'fontsize16_radiobutton'
      %execute this code when fontsize16_radiobutton is selected  
      set(handles.display_staticText,'FontSize',16);
    otherwise
       % Code for when there is no match.

end
%updates the handles structure
guidata(hObject, handles);