Creating Graphical User Interfaces

Saving Changes to the Address Book from the Menu

When you make changes to an address book, you need to save the current MAT-file, or save it as a new MAT-file. The File submenus Save and Save As enable you to do this. These menus, created with the Menu Editor, use the same callback, Save_Callback.

The callback uses the menu Tag property to identify whether Save or Save As is the callback object (i.e., the object whose handle is passed in as the first argument to the callback function). You specify the menu's Tag property with the Menu Editor.

Saving the Addresses Structure

The handles structure contains the Addresses structure, which you must save (handles.Addresses) as well as the name of the currently loaded MAT-file (handles.LastFile). When the user makes changes to the name or number, the Contact_Name_Callback or the Contact_Phone_Callback updates handles.Addresses.

Saving the MAT-File

If the user selects Save, the save command is called to save the current MAT-file with the new names and phone numbers.

If the user selects Save As, a dialog is displayed (uiputfile) that enables the user to select the name of an existing MAT-file or specify a new file. The dialog returns the selected filename and path. The final steps include

• Using fullfile to create a platform-independent pathname.
• Calling save to save the new data in the MAT-file.
• Updating the handles structure to contain the new MAT-file name.
• Calling guidata to save the handles structure.

Save_Callback Code Listing

• function Save_Callback(hObject, eventdata, handles)
  % Get the Tag of the menu selected
  Tag = get(hObject, 'Tag');
  % Get the address array
  Addresses = handles.Addresses;
  % Based on the item selected, take the appropriate action
  switch Tag
  case 'Save'
      % Save to the default addrbook file
      File = handles.LastFile;
      save(File,'Addresses')
  case 'Save_As'
      % Allow the user to select the file name to save to
      [filename, pathname] = uiputfile( ...
          {'*.mat';'*.*'}, ...
          'Save as');
      % If 'Cancel' was selected then return
      if isequal([filename,pathname],[0,0])
          return
      else
          % Construct the full path and save
          File = fullfile(pathname,filename);
          save(File,'Addresses')
          handles.LastFile = File;
          guidata(hObject, handles)
      end
  end
  

The Create New Menu

The Create New menu simply clears the Contact Name and Contact Phone # text fields to facilitate adding a new name and number. After making the new entries, the user must then save the address book with the Save or Save As menus. This callback sets the text String properties to empty strings:

• function New_Callback(hObject, eventdata, handles)
  set(handles.Contact_Name,'String','')
  set(handles.Contact_Phone,'String','')
  

Paging Through the Address Book - Prev/Next

The Address Book Resize Function