MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál stáhnout pdf (Strana 265)

An Address Book Reader

10-41

Determining Which Button Is Clicked

The callback defines an additional argument, str, that indicates which button,

Prev or Next, was clicked. For the Prev button Callback property (illustrated

above), the

Callback string includes 'Prev' as the last argument. The Next

button

Callback string includes 'Next' as the last argument. The value of str

is used in

case statements to implement each button’s functionality (see the

code listing below).

Paging Forward or Backward

Prev_Next_Callback gets the current index pointer and the addresses from the

handles structure and, depending on which button the user presses, the index

pointer is decremented or incremented and the corresponding address and

phone number are displayed. The final step stores the new value for the index

pointer in the

handles structure and saves the updated structure using

guidata.

Code Listing

function Prev_Next_Callback(hObject, eventdata,handles,str)

% Get the index pointer and the addresses

index = handles.Index;

Addresses = handles.Addresses;

% Depending on whether Prev or Next was clicked,

% change the display

switch str

case 'Prev'

% Decrease the index by one

i = index - 1;

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MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál Strana 265