Component-Based Software Engineering GUI Basics Paul J Krause

Swing Overview  Components in the Abstract Windowing Toolkit (AWT) rely on the local platform’s GUI capabilities  Most Swing components are light-weight components - not “weighed-down” by the local platform’s GUI capabilities

Swing Overview java.lang.Object java.awt.Component java.awt.Container javax.swing.JComponent add( ) setlayout( ) setBorder( ) setOpaque( ) setToolTipText( ) paint( ) repaint( )

GUI Building in Swing  Need at least one top-level container  This is the root of a “containment hierarchy” this consists of all the Swing components that appear within that container this consists of all the Swing components that appear within that container  Often, the root will be a Jframe

JFrame

Pattern for Using JFrame import java.awt.*; import java.awt.event.*; import javax.swing.*; public class MyFrame extends JFrame { public MyFrame( ) { Container c = getContentPane(); c.setFlowLayout( new FlowLayout() ); c.add( Name of component here ); }

main method public static void main( String args[ ] ) { MyFrame test = new MyFrame( ); test.setSize( length, width ); test.show( ); }

Inner Class for event handling private class ActionEventHandler implements ActionListener { public void actionPerformed( ActionEvent e ) { if ( e.getSource( ) == exitButton ) System.exit(0); else if ( e.getSource( ) == something else ) { do something else } }}

Listening for actions public class MyFrame extends JFrame { public MyFrame( ) { public MyFrame( ) { Container c = getContentPane(); Container c = getContentPane(); c.setFlowLayout( new FlowLayout() ); c.setFlowLayout( new FlowLayout() ); ActionEventHandler handler = new ActionEventHandler( ); ActionEventHandler handler = new ActionEventHandler( ); JButton exitButton = new JButton( “Exit” ); JButton exitButton = new JButton( “Exit” ); exitButton.addActionListener( handler ); exitButton.addActionListener( handler ); c.add( exitButton ); c.add( exitButton );}

TimeTestWindow demo

Using NetBeans  Building a GUI is much easier and quicker using a visual development environment  Will illustrate this using NetBeans  Example taken from Chapter 8 of NetBeans - The Definitive Guide by Tim Boudreau, Jesse Glick, Simeon Greene, Vaughn Spurlin & Jack Woehr, O’Reilly