MATLAB Creating Graphical User Interfaces

b = uicontrol('Style','pushbutton','Callback',@pushbutton_callback);

Here is the function definition for pushbutton_callback:

function pushbutton_callback(src,event)

display('Button pressed');

end

Notice that the function handle does not explicitly refer to any input arguments, but the

function declaration includes two input arguments. These two input arguments are

required for all callbacks you specify as a function handle. MATLAB passes these

arguments automatically when the callback executes. The first argument is the UI

component that triggered the callback. The second argument provides event data to the

callback function. If there is no event data available to the callback function, then

MATLAB passes the second input argument as an empty array. The following table lists

the callbacks and components that use event data.

Callback Property Name Component

WindowKeyPressFcn

WindowKeyReleaseFcn

WindowScrollWheel

figure

KeyPressFcn figure, uicontrol, uitable

KeyReleaseFcn figure, uicontrol, uitable

SelectionChangedFcn uibuttongroup

CellEditCallback

CellSelectionCallback

uitable

A benefit of specifying callbacks as function handles is that MATLAB checks the function

for syntax errors and missing dependencies when you assign the callback to the

component. If there is a problem in the callback function, then MATLAB returns an error

immediately instead of waiting for the user to trigger the callback. This behavior helps

you to find problems in your code before the user encounters them.

Specify a Cell Array

Use a cell array to specify a callback function that accepts additional input arguments

that you want to use in the function. The first element in the cell array is a function

handle. The other elements in the cell array are the additional input arguments you want

to use, separated by commas. The function you specify must define the same two input

10 Code a Programmatic App