MATLAB Creating Graphical User Interfaces

Write the Callback Function

This code is an example of a list box callback function in GUIDE. Associate this function

with the list box Callback property to make it execute when a selects an item in the list

box.

function listbox1_Callback(hObject, eventdata, handles)

% hObject handle to listbox1 (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns contents

% contents{get(hObject,'Value')} returns selected item from listbox1

items = get(hObject,'String');

index_selected = get(hObject,'Value');

item_selected = items{index_selected};

display(item_selected);

When the end user selects an item in the list box, the callback function performs the

following tasks:

• Gets all the items in the list box and stores them in the variable, items.


• Gets the numeric index of the selected item and stores it in the variable,
  index_selected.


• Gets the value of the selected item and stores it in the variable, item_selected.


• Displays the selected item in the MATLAB Command Window.

The example, “Interactive List Box App in GUIDE” on page 8-15 shows how to populate a

list box with directory names.

Pop-Up Menu

Populate Items in the Pop-Up Menu

If you are developing an app using GUIDE, use the pop-up menu CreateFcn callback to

add items to the pop-up menu.

This code is an example of a pop-up menu CreateFcn callback that populates the menu

with the items, Red, Green, and Blue.

function popupmenu1_CreateFcn(hObject, eventdata, handles)

% hObject handle to popupmenu1 (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

7 Programming a GUIDE App