Swing

Resources:

Quick reference

Layouts

To avoid deadlook starting a Swing program the main( ) should not call the Swing methods, but instead should submit a task to the event queue.

We can submit manipulations through SwingUtilities.invokeLater( ) .

Code: 

			
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
				
public class SwingConsole{
	private SwingConsole() {
		// Util Library
	}
	public static void run(final JFrame f, final int width, final int height) {
		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				f.setTitle(f.getClass().getSimpleName());
				f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				f.setSize(width, height);
				f.setVisible(true);
			}
		});
	}
}

JApplet, JFrame, JWindow, JDialog, JPanel, etc., can all contain and display Components.



Class inheritance hierarchy diagrams

Swing class tree UML diagramSwing UML class diagram

Swing class inheritance UML

Layout manager

A Container uses a LayoutManager (aggregation relationship)

Container

In Container, there’s a method called setLayout( ) that allows you to choose a different layout manager
All other JFC/Swing top-level containers contains aJRootPane as its only child. The content pane provided by the root pane should, as a rule, contain all the non-menu components displayed by the JFrame

JComponents

Container is used to group components. Frames, panels, and applets are examples of containers.


JComponent is a type of Container and a superclass of all the lightweight Swing components.

The GUI JComponent classes, such as JButton , JTextField , JTextArea , JComboBox , JList , JRadioButton , and JMenu , are subclasses of JComponent .


JButton

JButton jbtOK = new JButton("OK");
System.out.println(jbtOK instanceof JButton);
System.out.println(jbtOK instanceof AbstractButton);
System.out.println(jbtOK instanceof JComponent);
System.out.println(jbtOK instanceof Container);
System.out.println(jbtOK instanceof Component);
  • CheckBox and RadioBox inherit form JTogleButton. Both component behavior in the same way.
  • AbstractButton can be added to a ButtonGroup.

JTabbedPane

http://download.oracle.com/javase/tutorial/uiswing/components/tabbedpane.html
Inserting a tab:
  • addTab method handles the bulk of the work in setting up a tab in a tabbed pane. The addTab method has several forms, but they all use both a string title and the component to be displayed by the tab.
  • insertTab method, which lets you specify the index of the tab you're adding
Tab options:
  • setMnemonicAt(1, KeyEvent.VK_2);
  • pane.indexOfTabComponent(3)
  • pane.remove(3)


Component Events and Listeners
JComponent User Interaction that Generates an Event Event Object
Created 		Listener Interface the Event Handler Should Implement
method(s) needed
JTextField Pressing <Enter> ActionEvent ActionListener
actionPerformed
JTextArea
JButton Pressing the button
JRadioButton Selecting a radio button ItemEvent ItemListener
itemStateChanged
JCheckBox (De)selecting a checkbox
JComboBox Selecting an item
JList ListSelectionEvent ListSelectionListener
valueChanged
Any component Pressing/releasing mouse buttons MouseEvent MouseListener
mousePressed
mouseReleased
mouseClicked
mouseEntered
mouseExited
Moving/dragging mouse MouseMotionListener
mouseDragged
mouseMoved


Helper Classes

The helper classes, such as Graphics , Color , Font , FontMetrics , Dimension , and LayoutManager , are not subclasses of Component . They are used to describe the properties of GUI components, such as graphics context, colors, fonts, and dimension.


NOTE

  • JComponent not added during construction must call the container's validate() method in order to force a re-layout of the components (and thus the display of the new JComponent)
  • call dispone() method to close a window

Swing Event Model

Note

  • A listener receives a fired event and acts on that event
  • Listeners, source (of an event) and handlers can be separated
  • As a programmer, we create a listener object and register it (addXXXListener())with the componet that' firing the event
  • addXXListener VS removeXXXListener()