GUI Libraries in Java

General Information

Introduction to GUI

• reactive programming
• model-view-controller
• widgets; AWT versus Swing
• look-and-feel
• hierarchical windows and layout managers
• coordinate system
• graphics object

Key API's:

• Java API documentation for package
• Java API documentation for package

Reactive Programming

• Reactive.java
• Main.java

  currently active threads: 4
  0: Thread[main,5,main]
  1: Thread[AWT-EventQueue-0,6,main]
  2: Thread[SunToolkit.PostEventQueue-0,5,main]
  3: Thread[AWT-Motif,5,main]
        

Appearance is controlled by the invisible agent that notices that the window needs repainting. The programmer must override paint and created the appearance of the entire area (or cobble widgets together that take the responsiblity for their area upon themeselves). Many of the earlier applet examples were of this simple form where paint was overriden.

Example GUI Applications

• Draw.java Painting the appearance directly.

• Quit2.java Cobbling together widgets.

  
  

• HelloSwing.java

paint

1. whenever you're component is resized (in particular, when it is first mapped to the screen),
2. whenever the component is fully or partially exposed (that is, when a window that was covering it is moved out of the way), and
3. if you don't override the component's update method, paint will get called whenever the update method gets called (that is, whenever you call repaint()).

It is usually better to call repaint() then to call paint() directly, because if you call repaint() 10 times before the screen updater actually gets around to doing the painting, your paint method will only get called once, which is more efficient.

Threads and Swing

Updating a component while not executing in an event handler could possiblilty cause a deadlock. To avoid this problem use one of two SwingUtilities: invokeLater or invokeAndWait.

• How to Use Threads in the Sun tutorial.

Model-View-Controller

Java Swing, by Eckstein et al.

Java Swing, by Eckstein et al.

UI delegate = User-Interface delegate.

Widgets

A combination of a graphic symbol and some program code to perform a specific function, e.g., a scroll-bar or button. In the PC world a widget is sometimes known as a control. Windowing systems usually provide widget libraries containing commonly used widgets drawn in a certain style and with consistent behavior.

AWT versus Swing

AWT are said to be "heavyweight" because they have "peers" (platform specific constructs) that do the real work. Swing components are said to be "lightweight" most of the work is done by Java.

AWT Components

Button, Checkbox, Choice, Label, List, TextComponent, Scrollbar, Canvas
MenuComponent: MenuBar, MenuItem
Container:  Panel, Window

Swing Components

JButton, JCheckBox, JComboBox, JLabel, JList, JTextComponent, JSlider, JScrollBar, JProgressBar
Menus: JMenuBar
Fancy: JTable, JTree, JInternalFrame

Containers:  JPanel, JWindow, JFrame, JApplet, 
Specialty Containers:  JScrollPane, JLayeredPane, JSplitPane, JTabbedPane

Dialogs: JDialog, JFileChooser, JColorChooser
Other:  Borders

• AWT Widgets GIF (the source code to Widgets.java)
• Swing Widgets GIF (the source code to JWidgets.java)

Swing Tour

java -jar demo/jfc/SwingSet/SwingSet.jar

• Java SwingSet2 demo
• Java Web Start Demos

Look-and-Feel

Solaris

Swing Widgets (Metal)

java -Dswing.defaultlaf=com.sun.java.swing.plaf.motif.MotifLookAndFeel JWidgets

Swing Widgets (Motif)

Windows

Swing Widgets (Metal)

java -Dswing.defaultlaf=com.sun.java.swing.plaf.motif.MotifLookAndFeel JWidgets

Swing Widgets (Motif)

java -Dswing.defaultlaf=com.sun.java.swing.plaf.windows.WindowsLookAndFeel JWidgets

Swing Widgets (Windows)

Ubuntu

Swing Widgets (Ubuntu)

Swing Widgets (Ubuntu)

Swing Widgets (Ubuntu)

See all the Java SwingSet demo.

Hierarchical Windows

• class.
• class.

Notice that a container is a (extends a) component in the usual inheritance hierarchy. Some are containers --- they extend . Others components are widgets -- fundamental GUI units.

A particular GUI is orgainized by putting some set of widgets in a container. These containers (which are components) may be put in other containers and so on.

You only need one container (the window) and you can put all the widgets in it. But is far better to orgainize the widgets in small groups in their own containers. This leads to a second hierarchy.

 

All the components in a Java GUI will print themselves to System.err if you press control+shift+F1.

Coordinate System

Graphics Object

Java 2D

• Stroking and Filling Graphics Primitives [!!]
• Constructing Complex Shapes [??] binary shape operations: union, intersection, substraction, xor on a special type of Shape called an Area
• Compositing Graphics shows how to paint overlaping shapes
• User interaction -- hit testing
• Printing a Component

• Java 2D demo
• Java 2D demo

Shapes

Arc2D, Ellipse2D, Rectangle2D, RoundRectangle2D all extend RectangularShape. They are also specified using x, y, width, and height.

• Rectangle.java
  
• Arc.java
  
• Curve.java -- QuadCurve: quadratic parametric curve segment, CubicCurve: cubic parametric curve segment (Bézier)
  
• Shape.java
  
• CombiningShapes.java
• Pear.java
  
• Composite.java

Original (non "2D") Graphics

public abstract class Graphics extends Object {
   public void draw3DRect (int x, int y, int width, int height, boolean raised)
   public void drawArc (int x, int y, int width, int height, int startAngle, int arcAngle)
   public void drawLine (int x1, int y1, int x2, int y2)
   public void drawOval (int x, int y, int width, int height)
   public void drawPolygon (int[] xs, int[] ys, int n)
   public void drawRect (int x, in y, int width, int height)
   public void drawString (string str, int x, in y)
   public void drawImage (image img, int x, int y, int width, int height, ImageObserver obs
}

Color

    Color white     = new Color(255, 255, 255);
    Color lightGray = new Color(192, 192, 192);
    Color gray      = new Color(128, 128, 128);
    Color darkGray  = new Color(64, 64, 64);
    Color black     = new Color(0, 0, 0);
    Color red       = new Color(255, 0, 0);
    Color pink      = new Color(255, 175, 175);
    Color orange    = new Color(255, 200, 0);
    Color yellow    = new Color(255, 255, 0);
    Color green     = new Color(0, 255, 0);
    Color magenta   = new Color(255, 0, 255);
    Color cyan      = new Color(0, 255, 255);
    Color blue      = new Color(0, 0, 255);

brighter () is RGB / 0.7  (ie., 1.42 * RGB)
  darker () is RGB * 0.7

• ColorBlocks.java -- the predefined colors, a color gradient, and an alpha gradient.
  

Fonts

Dialog
Helvitica
TimesRoman
Courier
DialogInput
ZapfDingbats

style:  PLAIN, BOLD, ITALIC, Font.BOLD|Font.ITALIC

• font
• list font

Available Fonts:
  
  Akhbar MT
  ...

Images

• Example applets

Atomic Components

• HelloSwing.java --- illustrates form of the simplest stand-alone Java Swing application.
• Quit2.java --- illustrates events and terminating

JButton

• Application.java and ImageButton.java

JCheckBox

• Deli.java

JTextField

• TextForm.java

JFormattedTextField (J2SE 1.4)

JComboBox

• Patterns.java

JList

• List.java, CheckList.java, and ChangeList.java

You can specify a different selection mode by calling the setSelectionMode method on the list. The following table describes the three list selection modes:

Mode	Description	Example
SINGLE_SELECTION	Only one item can be selected at a time. When the user selects an item, any previously selected item is deselected first.
SINGLE_INTERVAL_SELECTION	Multiple, contiguous items can be selected. When the user begins a new selection range, any previously selected items are deselected first.
MULTIPLE_INTERVAL_SELECTION	The default. Any combination of items can be selected. The user must explicitly deselect items.

Events

• push buttons to play audio
• Button.java
• List.java
• ClosingWindowMonitor.java
• Mouse.java

AWTEvents

Event Category	Description
action	initiated by, e.g., buttons, to indicate a command should be performed
adjustment	initiated by, e.g., scrollbars, to indicate a value has been changed
ancester	initiated by any component when it has been reparented
component	initiated by any component when it has been moved or resized
focus	initiated by any component when it has lost or gained the focus
item	initiated by, e.g., list boxes, to indicate the state of an item has changed
input method	If the text component that's currently using the input method is an active client, the event is dispatched to that component. Otherwise, it is dispatched to a separate composition window.
internal frame	support for Swing JInternaFrame
invocation	An event which executes the run() method on a Runnable when dispatched by the AWT event dispatcher thread
key	initiated by a key press or release
mouse	initiated by a mouse movements or clicks
text	initiated by text componentes to indicate a change in the text
window	initiated by windows when closed, iconfied, etc.

ActionEvent	ActionListener actionPerformed(ActionEvent)	Button List TextField MenuItem
AdjustmentEvent	AdjustmentListener adjustmentValueChanged(AdjustedEvent)	Component
ComponentEvent	ComponentListener componentMoved(ComponentEvent) componentHidden(ComponentEvent) componentResized(ComponentEvent) componentShown(ComponentEvent)	Component
FocusEvent	FocusListener focusGained(FocusEvent) focusLost(FocusEvent)	Scrollbar
ItemEvent	ItemListener itemStateChanged(ItemEvent)	Checkbox MenuItem Choice List
KeyEvent	KeyListener keyPressed(KeyEvent) keyReleased(KeyEvent) keyTyped(KeyEvent)	Component
MouseEvent	MouseListener mousePressed(MouseEvent) mouseReleased(MouseEvent) mouseClicked(MouseEvent) mouseEntered(MouseEvent) mouseExited(MouseEvent)	Component
	MouseMotionListener mouseDragged(MouseEvent) mouseMoved(MouseEvent)	Component
TextEvent	TextListener textValueChanged(TextEvent)	TextComponent
WindowEvent	WindowListener windowClosing(WindowEvent) windowOpened(WindowEvent) windowIconified(WindowEvent) windowDeiconified(WindowEvent) windowClosed(WindowEvent) windowActivated(WindowEvent) windowDeactivated(WindowEvent)	Window

Adapter classes for java.awt (JDK 1.3)

Event Class	Listener Interface	Adapter Class
ComponentEvent	ComponentListener	ComponentAdapter
ContainerEvent	ContainerListener	ContainerAdapter
FocusEvent	FocusListener	FocusAdapter
HierarchyBoundsEvent	HierarchyBoundsListener	HierarchyBoundsAdapter
KeyEvent	KeyListener	KeyAdapter
MouseEvent	MouseListener	MouseAdapter
MouseMotionEvent	MouseMotionListener	MouseMotionAdapter
WindowEvent	WindowListener	WindowAdapter

Event Class	Listener Interface	Adapter Class
InternalFrameEvent	InternalFrameListener	InternalFrameAdapter
MouseInputEvent	MouseInputListener	MouseInputAdapter

• SetLAF.java Change look and feel dynamically and take screen shot and write PNG file.

Layout

Composite Components

• Main.java Date spinner. Notice the importance of the selected region.

JTable

• TableValues.java
• TableTest01.java
• TableTest02.java
• CurrencyRenderer.java
• GenderRenderer.java
• TableTest03.java
• GenderEditor.java
• TableTest04.java
• MultiLineHeaderRenderer.java
• TableTest05.java
• SortTableModel.java
• SortColumnHeaderRenderer.java
• SortMouseListener.java

Borders

Menu Bar

• Main.java
• ItemFactory.java

Data Transfer

• Main.java