939: Highlights

• If you want labels, text fields, and buttons in your application, then
  • Use JLabel instances to create labels.
  • Use JTextField instances to create text fields.
  • Use JButton instances to create new buttons.
  • Use getText to retrieve strings from text fields.
  • Use setText to insert strings into text fields.
• If you need to convert strings to integers, then use parseInt, from the Integer class.
• If you need to convert integers to strings, then use valueOf from the String class.
• If you want text fields and labels to initiate action, then define a listener:

   class LocalActionListener implements ActionListener { 
    public void actionPerformed(ActionEvent e) { 
     if (e.getSource() == text field or button) {                                 
       ... appropriate response ...; 
     } else if (e.getSource() == another text field or button) {                          
       ... appropriate response ...; 
     ... 
     } 
    }  
   }  
  

  and then add the listener to the text or button field:

  text field or button.addActionListener( 
    new LocalActionListener() 
  ); 
  

• If you want to lay out a group of text and button fields in a rectangular array, then instantiate the following pattern:

  setLayout(new GridLayout(rows, columns, 
                           row spacing, column spacing) 
           ); 
  ... 
  add(text field or button) 
  ... 
  

• If you want to deploy your own event creation and listening apparatus, then use the firePropertyChange method to create PropertyChangeEvent instances and call property-change listeners.
• If you want to define a property-change listener, then define a class that implements the PropertyChangeListener interface, then define the propertyChange method, and then connect an instance of your listener to a property-change-firing component using the addPropertyChangeListener method.