Creating Graphical User Interfaces

Output Function

The output function returns, to the command line, outputs that were generated during execution. It is executed when the opening function returns control and before control returns to the command line. This means that you must generate the outputs in the opening function, or call uiwait in the opening function to pause its execution while other callbacks generate outputs. See Example: Using the Modal Dialog to Confirm an Operation for an example that uses uiwait.

Naming and Template

GUIDE names the output function by appending _OutputFcn to the name of the M-file. This is an example of an output function template as it might appear in the mygui M-file.

• % --- Outputs from this function are returned to the command line.
  function varargout = mygui_OutputFcn(hObject, eventdata,...
                       handles)
  % varargout  cell array for returning output args (see VARARGOUT);
  % hObject    handle to figure
  % eventdata  reserved - to be defined in a future version of MATLAB
  % handles    structure with handles and user data (see GUIDATA)
   
  % Get default command line output from handles structure
  varargout{1} = handles.output;
  

Input Arguments

The output function has three input arguments: hObject, eventdata, and handles. They are the same as described in Component and Figure Callbacks.

Output Arguments

The output function has one output argument, varargout, which it returns to the command line. By default, the output function assigns handles.output to varargout. So the default output is the handle to the GUI, which was assigned to handles.output in the opening function.

You can change the output by:

• Changing the value of handles.output. It can be any valid MATLAB value including a structure or cell array.
• Adding output arguments to varargout.

• varargout is a cell array. It can contain any number of output arguments. By default, GUIDE creates just one output argument, handles.output. To create an additional output argument, create a new field in the handles structure and add it to varargout using a command similar to

  • varargout{2} = handles.second_output;
    

Initialization Callbacks in GUIDE

Managing Application-Defined Data

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