Creating Graphical User Interfaces

Running the GUI

The GUI is nonblocking and nonmodal since it is designed to be displayed while you perform other MATLAB tasks.

GUI Option Settings

This GUI uses the following GUI option settings:

• Resize behavior: User-specified
• Command-line accessibility: Off
• GUI M-file options selected:

• Generate callback function prototypes

  Application allows only one instance to run

Calling the GUI

You can call the GUI M-file with no arguments, in which case the GUI uses the default address book MAT-file, or you can specify an alternate MAT-file from which the GUI reads information. In this example, the user calls the GUI with a pair of arguments, address_book('book', 'my_list.mat'). The first argument, 'book', is a key word that  the M-file looks for in the opening function. If the M-file finds the key word, it knows to use the second argument as the MAT-file for the address book. Calling the GUI with this syntax is analogous calling it with a valid property-value pair, such as ('color', 'red'). However, since 'book' is not a valid figure property, in this example the opening function in the M-file includes code to recognize the pair ('book', 'my_list.mat'). 

Note that it is not necessary to use the key word 'book'. You could program the M-file to accept just the MAT-file as an argument, using the syntax address_book(my_list.mat). The advantage of calling the GUI with the pair ('book', my_list.mat') is that you can program the GUI to accept other user arguments, as well as valid figure properties, using the property-value pair syntax. The GUI can then identify which property the user wants to specify from the property name. 

The following code shows how to program the opening function to look for the key word 'book', and if it finds the key word, to use the MAT-file specified by the second argument as the list of contacts. 

• function address_book_OpeningFcn(hObject, eventdata, handles, varargin)
  % Choose default command line output for address_book
  handles.output = hObject;
  % Update handles structure
  guidata(hObject, handles);
  % User added code follows
  if nargin < 4
      % Load the default address book
      Check_And_Load([],handles);
      % If first element in varargin is 'book' and the second element is a
      % MATLAB file, then load that file
  elseif (length(varargin) == 2 & strcmpi(varargin{1},'book') & (2 == 
  exist(varargin{2},'file')))
      Check_And_Load(varargin{2},handles);
  else
      errordlg('File Not Found','File Load Error')
      set(handles.Contact_Name,'String','')
      set(handles.Contact_Phone,'String','')
  end
  

An Address Book Reader

Loading an Address Book Into the Reader