1. Java Programming Transparency No. 1 Lecture 9 Java GUI Cheng-Chia Chen

2. Java GUI Transparency No. 2 Contents 1.java GUI evolution 2.Swing Components and Containing Hierarchy 3.Layout Management 4.Java Event Model and Event Handling 5.javaBeans Reference:  The Java Tutorial on the trail: Creating a GUI with JFC/Swing

3. Java GUI Transparency No. 3 Evolution of Java GUI  Java 1.0 AWT built in 30 days, and it shows  Java 1.1 AWT significantly improved, but GUI not finished yet  Java 2 Swing: very different, vastly improved  This lecture cover Swing only.

4. Java GUI Transparency No. 4 Swing/JFC is very powerful  Start with the simple approach so you can create basic applications  Most of the time this will satisfy your needs  If you want to modify the standard elements, you can, but... You’ll have to work harder and learn more A number of big, thick books are available

5. Java GUI Transparency No. 5 Swing/JFC  Very easy to add keyboard accelerators, tooltips, graphics  Pluggable look and feel  Provides ways to change just about everything, but you must work to understand how

6. Java GUI Transparency No. 6 Swing Components and the containment hierarchy  Borders  Buttons  Checkboxes  ComboBoxes  Image Icons  Labels  Layered Panes and Internal Frames (MDI)  Lists and List Boxes  Menus  Popup Menus  Radio Buttons  Progress Bars  Scrolling Support  Scrollbars  Splitter Control  Tabbed Panes

7. Java GUI Transparency No. 7 Swing features and Conecpts  Components and the containment hierarchy  Swing Components and the Containment Hierarchy  Layout Management  Event Handling  Painting  Threads and Swing  More Swing Features and Concepts  The Anatomy of a Swing-Based Program

8. Java GUI Transparency No. 8 Swing Components and the Containment Hierarchy  An example:  Four components in this GUI: a frame, or main window (JFrame) --- top-level container a panel, sometimes called a pane (JPanel) --- intermediate container a button (JButton) --- atomic components a label (JLabel) --- atomic components

9. Java GUI Transparency No. 9  the containment hierarchy for the gui:

10. Java GUI Transparency No. 10  The code that adds the button and label to the panel, and the panel to the content pane: frame = new JFrame(...); button = new JButton(...); label = new JLabel(...); pane = new JPanel(); pane.add(button); pane.add(label); frame.getContentPane().add(pane, BorderLayout.CENTER);

11. Java GUI Transparency No. 11 Classification of swing components  Top-Level Containers The components at the top of any Swing containment hierarchy.  General-Purpose Containers Intermediate containers that can be used under many different circumstances.  Special-Purpose Containers Intermediate containers that play specific roles in the UI.  Basic Controls Atomic components that exist primarily to get input from the user; they generally also show simple state.  Uneditable Information Displays Atomic components that exist solely to give the user information.  Editable Displays of Formatted Information Atomic components that display highly formatted information that (if you choose) can be edited by the user.

12. Java GUI Transparency No. 12 top-level containers Frame ( and JFrame) Dialog ( and JDialog) Applet (and JApplet)

13. Java GUI Transparency No. 13 General-Purpose Containers Panel ( and JPanel) JToolBar JScrollPane JTabbedPane JSplitPane

14. Java GUI Transparency No. 14 Special-Purpose Containers JLayeredPane JInternalFrames Root Pane

15. Java GUI Transparency No. 15 Basic Controls JCheckBox JRadioButton JButton JMenu JMenuItem List ( and JList)

16. Java GUI Transparency No. 16 Basic Controls Choice ( and JComboBox) JTextField JSlider

17. Java GUI Transparency No. 17 Uneditable Information Displays Label ( and JLabel) JProgressBar JToolTip

18. Java GUI Transparency No. 18 Editable Displays of Formatted Information JTree JTextJTable FileDialog ( and JFileChooser) JColorChooser

19. Java GUI Transparency No. 19 Sturcture of the java.awt (AWT) package. Component {abstract} ComponentPeer ImageObserver LayoutManager Font TextComponent CheckboxCanvasButtonChoice Color Label TextFieldTextArea List Container {abstract } Scrollbar -parent -peer -layoutMgr

20. Java GUI Transparency No. 20 Layout Management  the GUIs of five programs, each of which displays five buttons.

21. Java GUI Transparency No. 21 Common layout tasks  Identical Buttons, almost identical codes. why do they look so different? use different layout managers to control the size and position of the buttons.  the common layout tasks: Setting the layout manager : JPanel pane = new JPanel(); pane.setLayout(new BorderLayout()); Providing hints about a component : privide size Hints : setMinimumSize(Dimension), setPreferredSize(..), setMaximumSize(..) provide alignmentHints: setAllignmentX(float), setAlignmentY(float) Putting space between components : the layout manager : can specify hgap and vgap. putting invisible component: empty border : best for components that have no default border, eg: JPanel, Jlabel

22. Java GUI Transparency No. 22 Event Handling  Every time the user types a character (KeyEvent) or pushes a mouse button( MouseEvent), an event occurs.  Any object can be notified of the event. implement the appropriate interface and be registered as an event listener on the appropriate event source.  Swing components can generate many kinds of events.

23. Java GUI Transparency No. 23 Example GUI Events  Act that results in the event Listener type  User clicks a button, presses Return while typing in a ActionListener text field, or chooses a menu item  User closes a frame (main window) WindowListener  User presses a mouse button while the cursor is over a component MouseListener  User moves the mouse over a component MouseMotionListener  Component becomes visible ComponentListener  Component gets the keyboard focus FocusListener  Table or list selection changes ListSelectionListener

24. Java GUI Transparency No. 24 Java Event Model  delegation ( or forwarding ) model l:EventListner b:EventSource system: l = new EventListener(…) b=new EventSource(…) addXXXListener(l) Event e1 occurs doXXXAction(e1) Event e2 occurs doXXXAction(e2) ….

25. Java GUI Transparency No. 25 How to Implement an Event Handler  Implement and instantiate an event Listener : public class MyClass implements XXXListener { …} XXXListener l = new XXXListener(…);  Register the eventListener as an listener on event source: aEventSource.addXXXListener( l ) ;  From now on, every time an event e occurs, the event source object will call the appropriate doXXXAction(e) from l.  Threads and Event Handling : Event-handling code executes in a single thread, the event-dispatching thread. => Event handlers should execute very quickly, Otherwise, the program's perceived performance will be poor. If needing lengthy operation, starting up another thread

26. Java GUI Transparency No. 26 How Painting Works 1. background 2. custom painting 3. border 4. children

27. Java GUI Transparency No. 27 More Swing Features and Concepts  Features that JComponent provides the ability to have borders, tool tips, and a configurable look and feel.  Icons Many Swing components -- notably buttons and labels -- can display images. You specify these images as Icon objects.  Actions provide support for sharing data and state between two or more components that can generate action events.  Pluggable Look & Feel support A single program can have any one of several looks and feels. can let the user determine the look and feel, or can specify the look and feel programatically.  Support for assistive technologies  Separate data and state models

28. Java GUI Transparency No. 28 Using Swing Components  The JComponent Class  Using Top-Level Containers  Using Intermediate Swing Containers  Using Atomic Components

29. Java GUI Transparency No. 29 The JComponent Class  JComponent  Container  Component  Tool tips: setToolTipText(String)  Borders The setBorder method allows you to specify the border that a component displays around its edges.  Keyboard-generated actions Using the registerKeyboardAction method, you can enable the user to use the keyboard, instead of the mouse, to operate the GUI.  Application-wide pluggable look and feel UIManager.setLookAndFeel(…)  Properties can associate one or more properties (name/object pairs) with any JComponent. putClientProperty(…), getClientProperty(…)

30. Java GUI Transparency No. 30  Support for layout get/set minimum/preferred/maximum Size(..). get/set alignmentX/Y(…)  Support for accessibility  Double buffering  Methods to increase efficiency getX(), getY(), getWidth(), getHeight(),…

31. Java GUI Transparency No. 31 The JComponent API  Customizing Component Appearance : get/set for properties: border, forground, background, font, opaque eg: setBorder(Border) / Border getBorder(), …  Setting Component State void setToolTipText(String) void setEnabled(boolean b), boolean isEnabled() void setLocale(Locale l), Locale getLocale() void setCursor(Cursor), Cursor getCursor() // mouse curser Icon void setVisible(boolean), boolean isVisible()  Handling Events : add/remove (component, mouse, mouseMotion, key, container, focus) Listenser get/set nextFocusComponent property requestFocus(), hasFocus() boolean contains(int x, int y), contains(Point) Component getComponentAt(int, int)

32. Java GUI Transparency No. 32  Painting Components void repaint(), repaint(int, int, int, int), repaint(Rectangle) void revalidate() : ReLay out the component and its affected containers. void paintComponent(Graphics)  Dealing with the Containment Hierarchy Component add(Component [, int index | Object constraint ] ) void remove(int), void remove(Component comp), void removeAll() JRootPane getRootPane() Container getParent() int getComponentCount() Component getComponent(int) Component[] getComponents()

33. Java GUI Transparency No. 33  Laying Out Components get/set LayoutManager property: layout get/set Dimension properties: minimumSize, preferredSize, maximumSize get/set float property: allignmentX, allignmentY  Getting Size and Position Information int getWidth(), getHeight(), getX(), getY() Dimension getSize(), Dimension getSize(Dimension) Rectangle getBounds(), Rectangle getBounds(Rectangle) Point getLocation(), getLocation(Point), getLocationOnScreen(); Insets getInsets()  Specifying Absolute Size and Position setLocation(int,int) setLocation(Point), setSize(int,int), setSize(Dimension), setBounds(int x,y,w,h), setBounds(Rectangle)

34. Java GUI Transparency No. 34 Using Top-Level Containers  three generally useful top-level container classes: JFrame, JDialog, and JApplet.  Each has a content pane that contains the visible components in the GUI.  Can optionally add a menu bar to a top-level container. positioned within the top-level container, but outside the content pane.

35. Java GUI Transparency No. 35  Adding Components to the Content Pane : frame.getContentPane().add(yellowLabel, BorderLayout.CENTER);  Adding a Menu Bar : frame.setJMenuBar(cyanMenuBar);  The Root Pane :

36. Java GUI Transparency No. 36 How to Make Frames (Main Windows)  code creates and  sets up the frame

37. Java GUI Transparency No. 37 the code public static void main(String s[]) { JFrame frame = new JFrame("FrameDemo"); frame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) {System.exit(0);} }); //...create a blank label, set its preferred size... frame.getContentPane().add(emptyLabel, BorderLayout.CENTER); frame.pack(); frame.setVisible(true); }

38. Java GUI Transparency No. 38 JFrame APIs  Constructors: JFrame(), JFrame(String)  void setDefaultCloseOperation(int), int getDefaultCloseOperation() Possible choices: DO_NOTHING_ON_CLOSE, HIDE_ON_CLOSE (the default), DISPOSE_ON_CLOSE  void setContentPane(Container), Container getContentPane()  void setJMenuBar(JMenuBar), JMenuBar getJMenuBar()  …

39. Java GUI Transparency No. 39 Using Intermediate Swing Containers  Panel The most flexible, frequently used intermediate container.  Scroll Pane Provides scroll bars around a large or growable component.  Split Pane Displays two components in a fixed amount of space, letting the user adjust the amount of space devoted to each component.  Tabbed Pane Contains multiple components but shows only one at a time. The user can easily switch between components.  Tool Bar Holds a group of components (usually buttons) in a row or column, optionally allowing the user to drag the tool bar into different locations.

40. Java GUI Transparency No. 40 special intermediate containers  Internal Frame Looks like a frame and has much the same API, but must appear within another window.  Layered Pane Provides a third dimension, depth, for positioning components. You specify the position and size of each component. One type of layered pane, a desktop pane, is designed primarily to contain and manage internal frames.  Root Pane : Provides behind-the-scenes support to top-level containers.

41. Java GUI Transparency No. 41 How to Use Panels

42. Java GUI Transparency No. 42  Setting the Layout Manager : JPanel aPanel = new JPanel(); aPanel.setLayout(new BorderLayout());  Adding Components aFlowPanel.add(aComponent); aFlowPanel.add(anotherComponent); aBorderPanel.add(aComponent, BorderLayout.CENTER); aBorderPanel.add(anotherComponent, BorderLayout.SOUTH);

43. Java GUI Transparency No. 43 The Panel API  Constructors: JPanel(), JPanel(LayoutManager)  void add(Component [, Object ] [, int ]),  void add(String, Component)  int getComponentCount()  Component getComponent(int)  Component[] getComponents()  Component getComponentAt( [int, int | Point] )  void remove(Component), void remove(int), void removeAll()  void setLayout(LayoutManager), LayoutManager getLayout()

44. Java GUI Transparency No. 44 How to Use Scroll Panes textArea = new JTextArea(5, 30); JScrollPane scrollPane = new JScrollPane(textArea);... contentPane.setPreferredSize(new Dimension(400, 100));... contentPane.add(scrollPane, BorderLayout.CENTER);

45. Java GUI Transparency No. 45 How to use Split Pane

46. Java GUI Transparency No. 46 the code //Create a split pane with the two scroll panes in it. splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, listScrollPane, pictureScrollPane); splitPane.setOneTouchExpandable(true); splitPane.setDividerLocation(150); //Provide minimum sizes for the two components in the split pane Dimension minimumSize = new Dimension(100, 50); listScrollPane.setMinimumSize(minimumSize); pictureScrollPane.setMinimumSize(minimumSize);

47. Java GUI Transparency No. 47 How to Use Tool Bars

48. Java GUI Transparency No. 48 public ToolBarDemo() {... JToolBar toolBar = new JToolBar(); addButtons(toolBar);... JPanel contentPane = new JPanel(); contentPane.setLayout(new BorderLayout());... contentPane.add(toolBar, BorderLayout.NORTH); contentPane.add(scrollPane, BorderLayout.CENTER);... }

49. Java GUI Transparency No. 49 protected void addButtons(JToolBar toolBar) { JButton button = null; //first button button = new JButton(new ImageIcon("images/left.gif"));... toolBar.add(button); //second button button = new JButton(new ImageIcon("images/middle.gif"));... toolBar.add(button); //third button button = new JButton(new ImageIcon("images/right.gif"));... toolBar.add(button); }  Other methods: isFloatable(), setFloatable(boolean) addSeparator()

50. Java GUI Transparency No. 50 Using Atomic Components  The following atomic components exist primarily to get input from the user:  Button, Check Box, Radio Button Provides easy-to-use, easy-to-customize button implementations.  Combo Box Provides both uneditable and editable combo boxes -- buttons that bring up menus of choices.  List Displays a group of items that the user can choose.  Menu Includes menu bar, menu, and menu item implementations, including specialized menu items such as check box menu items.  Slider Lets the user choose one of a continuous range of values.  Text Field Lets the user enter a single line of text data.

51. Java GUI Transparency No. 51  Some atomic components exist only to give information:  Label : Presents some text, an icon, or both.  Progress Bar : Displays progress toward a goal.  Tool Tip : Brings up a small window that describes another component.  The rest of the atomic components provide formatted information and a way of editing it:  Color Chooser : A UI for choosing colors; can be used inside or outside a dialog.  File Chooser :A UI for choosing files and directories.  Table: An extremely flexible component that displays data in a grid format.  Text Support : A framework including everything from simple text components, such as text fields, to a full-featured, extensible kit for building text editors.  Tree : A component that displays hierarchical data.

52. Java GUI Transparency No. 52 How to Use Buttons, Check Boxes, and Radio Buttons ImageIcon leftButtonIcon = new ImageIcon("images/right.gif") b1 = new JButton("Disable middle button", leftButtonIcon); b1.setVerticalTextPosition(AbstractButton.CENTER); b1.setHorizontalTextPosition(AbstractButton.LEFT); b1.setMnemonic(KeyEvent.VK_D); b1.setActionCommand("disable"); b1.addActionListener(this); b1.setToolTipText(“… ");

53. Java GUI Transparency No. 53  // can use setText(“ … ”) for multiFonts text  b1 = new JButton(" D isable “ + " middle button ", leftButtonIcon);

54. Java GUI Transparency No. 54 How to Use Check Boxes

55. Java GUI Transparency No. 55 the code //In initialization code: chinButton = new JCheckBox("Chin"); chinButton.setMnemonic(KeyEvent.VK_C); chinButton.setSelected(true); glassesButton = new JCheckBox("Glasses"); glassesButton.setMnemonic(KeyEvent.VK_G); glassesButton.setSelected(true); … // Register a listener for the check boxes. CheckBoxListener myListener = new CheckBoxListener(); chinButton.addItemListener(myListener); … teethButton.addItemListener(myListener);

56. Java GUI Transparency No. 56 How to use RadioButtons  Radio buttons are groups of buttons in which, by convention, only one button at a time can be selected.  Swing release supports radio buttons with the JRadioButton and ButtonGroup classes.

57. Java GUI Transparency No. 57 //In initialization code: // Create the radio buttons. JRadioButton birdButton = new JRadioButton(birdString); birdButton.setMnemonic(KeyEvent.VK_B); birdButton.setActionCommand(birdString); birdButton.setSelected(true); … // Group the radio buttons. ButtonGroup group = new ButtonGroup(); group.add(birdButton); group.add(catButton); group.add(dogButton); group.add(rabbitButton); group.add(pigButton);

58. Java GUI Transparency No. 58 // Register a listener for the radio buttons. RadioListener myListener = new RadioListener(); birdButton.addActionListener(myListener); catButton.addActionListener(myListener); dogButton.addActionListener(myListener); rabbitButton.addActionListener(myListener); pigButton.addActionListener(myListener);... class RadioListener implements ActionListener... { public void actionPerformed(ActionEvent e) { picture.setIcon(new ImageIcon("images/" + e.getActionCommand() + ".gif")); }

59. Java GUI Transparency No. 59 The event listener class CheckBoxListener implements ItemListener { public void itemStateChanged(ItemEvent e) {... Object source = e.getItemSelectable(); if (source == chinButton) { //...make a note of it... } else if (source == glassesButton) { //...make a note of it... } else if (source == hairButton) { //...make a note of it... } else if (source == teethButton) { //...make a note of it... } if (e.getStateChange() == ItemEvent.DESELECTED) //...make a note of it... picture.setIcon(/* new icon */);... } }

60. Java GUI Transparency No. 60 ColorChooser

61. Java GUI Transparency No. 61 final JLabel banner = new JLabel("Welcome to the Tutorial Zone!", JLabel.CENTER); banner.setForeground(Color.yellow);... final JColorChooser tcc = new ColorChooser ( banner.getForeground()); // initial selected color... getContentPane().add(tcc, BorderLayout.CENTER);  A color chooser uses an instance of ColorSelectionModel to contain and manage the current selection, which fires a change event whenever the user changes the color in the color chooser.

62. Java GUI Transparency No. 62  The example program registers a change listener with the color selection model so that it can update the banner at the top of the window. The following code registers and implements the change listener: tcc.getSelectionModel().addChangeListener( new ChangeListener() { public void stateChanged(ChangeEvent e) { Color newColor = tcc.getColor(); banner.setForeground(newColor); } } );

63. Java GUI Transparency No. 63 File Chooser

64. Java GUI Transparency No. 64 //Create a file chooser final JFileChooser fc = new JFileChooser();... // Event Handler for the OPenFile button public void actionPerformed(ActionEvent e) { // contianer int returnVal = fc.showOpenDialog(FileChooserDemo.this); if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); //this is where a real application would open the file. log.append("Opening: " + file.getName() + "." + newline); } else { log.append("Open command cancelled by user." + newline); } }

65. Java GUI Transparency No. 65 Label

66. Java GUI Transparency No. 66 ImageIcon icon = new ImageIcon("images/middle.gif");... label1 = new JLabel("Image and Text", icon, JLabel.CENTER); //Set the position of the text, relative to the icon: label1.setVerticalTextPosition(JLabel.BOTTOM); label1.setHorizontalTextPosition(JLabel.CENTER); label2 = new JLabel("Text-Only Label"); label3 = new JLabel(icon); //Add labels to the JPanel. add(label1); add(label2); add(label3);

67. Java GUI Transparency No. 67 Using HTML on a Label  The action listener for the button executes this single line of code:  theLabel.setText(htmlTextArea.getText());

68. Java GUI Transparency No. 68 Combo Boxes  very different forms: uneditable and editable.  Uneditable Combo Box: Editable Como Box

69. Java GUI Transparency No. 69 String[] petStrings = { "Bird", "Cat", "Dog", "Rabbit", "Pig" }; // Create the combo box, select item at index 4. // Indices start at 0, so 4 specifies the pig. JComboBox petList = new JComboBox(petStrings); petList.setSelectedIndex(4);... petList.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { JComboBox cb = (JComboBox)e.getSource(); String petName = (String)cb.getSelectedItem(); picture.setIcon(new ImageIcon("images/" + petName + ".gif")); } });

70. Java GUI Transparency No. 70 String[] patternExamples = { "dd MMMMM yyyy", "dd.MM.yy", "MM/dd/yy", "yyyy.MM.dd G 'at' hh:mm:ss z", "EEE, MMM d, ''yy", "h:mm a", "H:mm:ss:SSS", "K:mm a,z", "yyyy.MMMMM.dd GGG hh:mm aaa" };... JComboBox patternList = new JComboBox(patternExamples); patternList.setEditable(true); patternList.addActionListener(...);...

71. Java GUI Transparency No. 71 How to Use Lists

72. Java GUI Transparency No. 72 //...where member variables are declared: static Vector imageList; … // not limited to Strings // Create the list of images and put it in a scroll pane JList list = new JList(imageList); list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);... JScrollPane listScrollPane = new JScrollPane(list);  possible selection modes: SINGLE_SELECTION SINGLE_INTERVAL_SELECTION MULTIPLE_INTERVAL_SELECTION

73. Java GUI Transparency No. 73  JList fires list selection events whenever the selection changes.  You can process these events by adding a list selection listener to the list with the addListSelectionListener method.  A list selection listener must implement one method: valueChanged.

74. Java GUI Transparency No. 74 public void valueChanged(ListSelectionEvent e) { if (e.getValueIsAdjusting()) return; JList theList = (JList)e.getSource(); if (theList.isSelectionEmpty()) { picture.setIcon(null); } else { int index = theList.getSelectedIndex(); ImageIcon newImage = new ImageIcon("images/" + (String)imageList.elementAt(index)); picture.setIcon(newImage); picture.setPreferredSize(new Dimension( newImage.getIconWidth(), newImage.getIconHeight() )); picture.revalidate(); }

75. Java GUI Transparency No. 75 Adding Items to and Removing Items from a List  ListModel listModel = new DefaultListModel();  listModel.addElement("Alison Huml");  listModel.addElement("Kathy Walrath");  listModel.addElement("Lisa Friendly");  listModel.addElement("Mary Campione");  list = new JList(listModel);

76. Java GUI Transparency No. 76 public void actionPerformed(ActionEvent e) { int index = list.getSelectedIndex(); // or int[ ] getSelectedIndecies() listModel.remove(index); int size = listModel.getSize(); //Nobody's left, disable firing if (size == 0) { fireButton.setEnabled(false); //Adjust the selection } else { //removed item in last position if (index == listModel.getSize()) index--; //otherwise select same index list.setSelectedIndex(index); } }

77. Java GUI Transparency No. 77 How to Use Menus ( with JMenu and JMenuBar)

78. Java GUI Transparency No. 78 The Menu Component Hierarchy

79. Java GUI Transparency No. 79 Creating Menus //in the constructor for a JFrame subclass: JMenuBar menuBar; JMenu menu, submenu; JMenuItem menuItem; JCheckBoxMenuItem cbMenuItem; JRadioButtonMenuItem rbMenuItem;... //Create the menu bar. menuBar = new JMenuBar(); setJMenuBar(menuBar);

80. Java GUI Transparency No. 80 //Build the first menu. menu = new JMenu("A Menu"); menu.setMnemonic(KeyEvent.VK_A); menu.getAccessibleContext().setAccessibleDescription( "The only menu in this program that has menu items"); menuBar.add(menu); //a group of JMenuItems menuItem = new JMenuItem("A text-only menu item", KeyEvent.VK_T); menuItem.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_1, ActionEvent.ALT_MASK)); menuItem.getAccessibleContext().setAccessibleDescription( "This doesn't really do anything"); menu.add(menuItem); …

81. Java GUI Transparency No. 81 //a group of radio button menu items menu.addSeparator(); ButtonGroup group = new ButtonGroup(); rbMenuItem = new JRadioButtonMenuItem("A radio button menu item"); rbMenuItem.setSelected(true); rbMenuItem.setMnemonic(KeyEvent.VK_R); group.add(rbMenuItem); menu.add(rbMenuItem); rbMenuItem = new JRadioButtonMenuItem("Another one"); rbMenuItem.setMnemonic(KeyEvent.VK_O); group.add(rbMenuItem); menu.add(rbMenuItem);

82. Java GUI Transparency No. 82 //a group of check box menu items menu.addSeparator(); cbMenuItem = new JCheckBoxMenuItem("A check box menu item"); cbMenuItem.setMnemonic(KeyEvent.VK_C); menu.add(cbMenuItem); cbMenuItem = new JCheckBoxMenuItem("Another one"); cbMenuItem.setMnemonic(KeyEvent.VK_H); menu.add(cbMenuItem);

83. Java GUI Transparency No. 83 //a submenu menu.addSeparator(); submenu = new JMenu("A submenu"); submenu.setMnemonic(KeyEvent.VK_S); menuItem = new JMenuItem("An item in the submenu"); menuItem.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_2, ActionEvent.ALT_MASK)); submenu.add(menuItem); menuItem = new JMenuItem("Another item"); submenu.add(menuItem); menu.add(submenu); //Build second menu in the menu bar. menu = new JMenu("Another Menu"); menu.setMnemonic(KeyEvent.VK_N); menu.getAccessibleContext().setAccessibleDescription( "This menu does nothing"); menuBar.add(menu);

84. Java GUI Transparency No. 84 Handling Events from Menu Items  To detect when the user selects a JMenuItem, you can listen for action events (just as you would for a JButton).  To detect when the user selects a JRadioButtonMenuItem, you can listen for either action events or item events.  For JCheckBoxMenuItems, you generally listen for item events public class MenuDemo... implements ActionListener, ItemListener {... public void actionPerformed(ActionEvent e) {… } public void itemStateChanged(ItemEvent e) {... }

85. Java GUI Transparency No. 85 Bringing Up a Popup Menu //Create the popup menu. JPopupMenu popup = new JPopupMenu(); menuItem = new JMenuItem("A popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); menuItem = new JMenuItem("Another popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); //Add listener to components that can bring up popup menus. MouseListener popupListener = new PopupListener(); output.addMouseListener(popupListener); menuBar.addMouseListener(popupListener);...

86. Java GUI Transparency No. 86 class PopupListener extends MouseAdapter { public void mousePressed(MouseEvent e) { maybeShowPopup(e); } public void mouseReleased(MouseEvent e) { maybeShowPopup(e); } private void maybeShowPopup(MouseEvent e) { if (e.isPopupTrigger()) { popup.show(e.getComponent(), e.getX(), e.getY()); } } }

87. Java GUI Transparency No. 87 Using Text Components  JTextComponent Hierarchy

88. Java GUI Transparency No. 88  An Example of Using Each Text Component

89. Java GUI Transparency No. 89 // An Example of Using a Text Field JTextField textField = new JTextField(10); textField.setActionCommand(textFieldString); textField.addActionListener(this); //An Example of Using a Password Field JPasswordField passwordField = new JPasswordField(10); passwordField.setActionCommand(passwordFieldString); passwordField.addActionListener(this); // Eevent handler for both components public void actionPerformed(ActionEvent e) { … if (e.getActionCommand().equals(textFieldString)) { JTextField source = (JTextField)e.getSource(); actionLabel.setText(prefix + source.getText() + "\""); } else { JPasswordField source = (JPasswordField)e.getSource(); actionLabel.setText(prefix + new String(source.getPassword()) + "\"“ ) ; } }

90. Java GUI Transparency No. 90 Using Text Area JTextArea textArea = new JTextArea( "This is an editable JTextArea " + "that has been initialized with the setText method. " + "A text area is a \"plain\" text component, " + "which means that although it can display text " + "in any font, all of the text is in the same font." ); textArea.setFont( new Font("Serif", Font.ITALIC, 16)); textArea.setLineWrap(true); textArea.setWrapStyleWord(true);

91. Java GUI Transparency No. 91 JEditorPane  the foundation for Swing's styled text components and provides the mechanism through which you can add support for custom text formats.  Using an Editor Pane to Display Text from a URL: JEditorPane editorPane = new JEditorPane(); editorPane.setEditable(false);...//create a URL object for the TextSamplerDemoHelp.html file... try { editorPane.setPage(url); } catch (IOException e) { System.err.println("Attempted to read a bad URL: " + url); }

92. Java GUI Transparency No. 92 Using a Text Pane JTextPane textPane = new JTextPane(); String[] initString = { /*... fill array with initial text... */ }; String[] initStyles = { /*... fill array with names of styles... */ }; //Create the styles we need. initStylesForTextPane(textPane); Document doc = textPane.getDocument(); //Load the text pane with styled text. try { for (int i=0; i < initString.length; i++) { doc.insertString(doc.getLength(), initString[i], textPane.getStyle(initStyles[i])); } } catch (BadLocationException ble) { System.err.println("Couldn't insert initial text."); }

93. Java GUI Transparency No. 93 How to Use Border

94. Java GUI Transparency No. 94 Layout components within a container  Probably different than other GUIs you’ve used  All code, no resources  Components are placed on panel using “layout manager” based on the order in which you add( ) the components  Size, shape and placement quite different depending on layout manager  Applet and application window size also affects layout

95. Java GUI Transparency No. 95 Types of Layouts  FlowLayout  BorderLayout  GridLayout  CardLayout  GridBagLayout  BoxLayout  NullLayout

96. Java GUI Transparency No. 96 FlowLayout  Components “flow” onto form left-to-right and top-to-bottom  Components take on “normal” size

97. Java GUI Transparency No. 97 The Code Container contentPane = getContentPane(); contentPane.setLayout(new FlowLayout()); contentPane.add(new JButton("Button 1")); contentPane.add(new JButton("2")); contentPane.add(new JButton("Button 3")); contentPane.add(new JButton("Long-Named Button 4")); contentPane.add(new JButton("Button 5"));

98. Java GUI Transparency No. 98 The FlowLayout API  Three constructors: public FlowLayout() public FlowLayout(int alignment) public FlowLayout(int alignment, int horizontalGap, int verticalGap)  The alignment argument must have one of the values : FlowLayout.LEFT, FlowLayout.CENTER, FlowLayout.RIGHT.  horizontalGap and verticalGap specify the number of pixels to put between components. default gap value = 5 pixels.  Properties: Alignment, Hgap, Vgap: int, RW,

99. Java GUI Transparency No. 99 BorderLayout  Container divided into five regions: West, North, East, South, Center.

100. Java GUI Transparency No. 100 Example public class BorderLayout1 extends JApplet { public void init() { Container cp = getContentPane(); cp.setLayout(new BorderLayout()); // default is FlowLayout cp.add(new JButton("North"), BorderLayout.NORTH); // cp.add(BorderLayout.NORTH, new JButton("North")); // also ok! // cp.add(new JButton("North"), “North”); // also ok! cp.add(BorderLayout.SOUTH, new JButton("South")); cp.add(BorderLayout.EAST, new JButton("East")); cp.add(BorderLayout.WEST, new JButton("West")); cp.add(BorderLayout.CENTER, new JButton("Center")); }  Default for most things

101. Java GUI Transparency No. 101 Additional properties of BorderLayout  (Horizontal and Vertical ) Gaps between components  constructor: BorderLayout(int hgap, int vgap)  methods: void setHgap(int) void setVgap(int)

102. Java GUI Transparency No. 102 GridLayout  Organized in rows & columns

103. Java GUI Transparency No. 103 The code  Container contentPane = getContentPane(); contentPane.setLayout(new GridLayout(3,2)); contentPane.add(new JButton("Button 1")); contentPane.add(new JButton("2")); contentPane.add(new JButton("Button 3")); contentPane.add(new JButton("Long-Named Button 4")); contentPane.add(new JButton("Button 5"));  APIs: public GridLayout(int rows, int columns [, int hgap, int vgap ])

104. Java GUI Transparency No. 104 Cardlayout  Use JTabbedPane instead. import java.awt.*; public class main extends JApplet implement ActionListner { CardLayout cards = new CardLayout(); JButton b1 = new JButton(“one”), …, b3 = new JButton(“three”); b1.addActionListner( this); … ; b3.addActionListner(this) public void init() { setLayout( cards ); add( new Button("one"), "one" ); add( new Button("two"), "two" ); add( new Button("three"), "three" ); } public void actionPerformed( ActionEvent e) { cards.next( this ); } }

105. Java GUI Transparency No. 105 CardLayout API  void first(Container)  void next(Container)  void previous(Container)  void last(Container)  void show(Container, String cardID) show card identified by cardID.

106. Java GUI Transparency No. 106 GridBagLayout  Flexible layout manager that aligns components horizontally and vertically, without requiring that the components be the same size  Quite a mess to program Must use GridBagConstraints This is what happens without resources  You can accomplish a lot by combining other layout managers.  To make it easier, Swing has BoxLayout

107. Java GUI Transparency No. 107 BoxLayout  Place all components in a row or in a column.  Much of the benefit of GridBagLayout without the pain  Has helper class Box which uses BoxLayout and builds components for you

108. Java GUI Transparency No. 108 BoxLayout

109. Java GUI Transparency No. 109 South Center JPanel(BoxLayout(V)) label rigidArea(0,5) JScrollPane JButton HorizontalGlue rigidArea(10,0) JPanel (BorderLayout) The Layout structure JPanel(BoxLayout(H))

110. Java GUI Transparency No. 110 The Code JScrollPane listScroller = new JScrollPane(list); listScroller.setPreferredSize(new Dimension(250, 80)); listScroller.setMinimumSize(new Dimension(250, 80)); listScroller.setAlignmentX(LEFT_ALIGNMENT);... //Lay out the label and scroll pane from top to bottom. JPanel listPane = new JPanel(); listPane.setLayout(new BoxLayout(listPane, BoxLayout.Y_AXIS)); JLabel label = new JLabel(labelText); listPane.add(label); listPane.add(Box.createRigidArea(new Dimension(0,5))); listPane.add(listScroller); listPane.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));

111. Java GUI Transparency No. 111 // Lay out the buttons from left to right. JPanel buttonPane = new JPanel(); buttonPane.setLayout(new BoxLayout(buttonPane, BoxLayout.X_AXIS)); buttonPane.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10)); buttonPane.add(Box.createHorizontalGlue()); buttonPane.add(cancelButton); buttonPane.add(Box.createRigidArea(new Dimension(10, 0))); buttonPane.add(setButton); // Put everything together, using the content pane's BorderLayout. Container contentPane = getContentPane(); contentPane.add(listPane, BorderLayout.CENTER); contentPane.add(buttonPane, BorderLayout.SOUTH);

112. Java GUI Transparency No. 112 Box Layout Features  the box layout takes the components‘ alignments and minimum, preferred, and maximum sizes into account.  Respect each component's requested minimum and maximum heights.  Use preferred height ( or weight ) as default.  layout principles: tries to make all of its container's components equally wide -- as wide as the largest preferred width. container wider => make all the components as wide as the container. If the components aren't all the same width then X alignment comes into play.

113. Java GUI Transparency No. 113 Container wider than maximumSize  All components’s AllignmentX are LEFT_ALLIGNMENT(0.0)  All components’s AllignmentX are CENTER_ALLIGNMENT(0.5)  All components’s AllignmentX are RIGHT_ALLIGNMENT(1.0)

114. Java GUI Transparency No. 114  Components have different allignmentXs: 0.0, 0.5, 1.0.

115. Java GUI Transparency No. 115 When no component has maximumSize  same allignmentX => made as wide as their container.  different allignmentX : components with an X alignment of 0.0 (left) or 1.0 (right) will be smaller. components with an intermediate X alignment will be as wide as their container

116. Java GUI Transparency No. 116 Using Invisible Components as Filler  to have space between components: add an empty border to one or both components, or insert invisible components to provide the space. use Box class to create invisible components.  Creating invisible components with Box and Box.Filler. TypeSizeConstraintHowToCreate rigidAreaBox.createRigidArea(size) glue horizontalBox.createHorizontalGlue() verticalBox.createVerticalGlue() custom Box.Fillernew Box.Filler(minSize, prefSize, maxSize)

117. Java GUI Transparency No. 117 Rigid area  Use this when you want a fixed-size space between two components.  container.add(firstComponent);  container.add(Box.createRigidArea(new Dimension(5,0)));  container.add(secondComponent);

118. Java GUI Transparency No. 118 Glue  container.add(firstComponent);  container.add(Box.createHorizontalGlue());  container.add(secondComponent);

119. Java GUI Transparency No. 119 Custom Box.Filler // ensure 5~100 pixels b/t components and 100 px height container.add(firstComponent); Dimension minSize = new Dimension(5, 100); Dimension prefSize = new Dimension(5, 100); Dimension maxSize = new Dimension(Short.MAX_VALUE, 100); container.add(new Box.Filler(minSize, prefSize, maxSize)); container.add(secondComponent);

120. Java GUI Transparency No. 120 Specifying Component Sizes  change the minimum, preferred, and maximum sizes in two ways:  Invoking setXxxSize method ( defined by the JComponent class). comp.setMinimumSize(new Dimension(50, 25)); comp.setPreferredSize(new Dimension(50, 25)); comp.setMaximumSize(new Dimension(Short.MAX_VALUE, Short.MAX_VALUE ));  Overriding getXxxSize method:...//in a subclass of a component class: public Dimension getMaximumSize() { size = getPreferredSize(); size.width = Short.MAX_VALUE; return size; }

121. Java GUI Transparency No. 121 The Box and BoxLayout API  Constructors: BoxLayout(Container, int axis) Box(int axies) // create a Box : subclass of Container but not JComponent static Box createHorizontalBox() // = new Box(BoxLayout.X_AXIS) static Box createVerticalBox()  Constructors or methods creating Space Fillers Component createRigidArea(Dimension) Create a rigid lightweight component. Component createHorizontalGlue() Component createVerticalGlue() Component createGlue() Create a glue lightweight component. Horizontal glue and vertical glue can be very useful. Component createHorizontalStrut() Component createVerticalStrut() Create a "strut" lightweight component. We recommend using rigid areas instead of struts. Box.Filler(Dimension, Dimension, Dimension)

122. Java GUI Transparency No. 122 Null Layout (absolute Positioning)  setLayout(null);  Programmers are responsible for setting the size and position of each component. ( via setBounds(x, y, witdth, height))

123. Java GUI Transparency No. 123 The code public class NoneWindow extends JFrame {... private boolean laidOut = false; private JButton b1, b2, b3; public NoneWindow() { Container contentPane = getContentPane(); contentPane.setLayout(null); b1 = new JButton("one"); contentPane.add(b1); b2 = new JButton("two"); contentPane.add(b2); b3 = new JButton("three"); contentPane.add(b3); Insets insets = contentPane.getInsets(); b1.setBounds(25 + insets.left, 5 + insets.top, 75, 20); b2.setBounds(55 + insets.left, 35 + insets.top, 75, 20); b3.setBounds(150 + insets.left, 15 + insets.top, 75, 30);... }... }

124. Java GUI Transparency No. 124 Event Handling  Not limited to ActionListener InputEvent: KeyEvent, MouseEvent, MouseMotionEvent, ContainerEvent, ComponentEvent,…  Each type of event represented by a class  Component responds to an event by making an event object and calling each “listener” registered for that event  An event listener implements a particular listener interface using an inner class  addXXXListener( ) adds a listener to your component, removeXXXListener( ) un-registers it

125. Java GUI Transparency No. 125 Java Event Model  delegation ( or forwarding ) model l:EventListner b:EventSource system: l = new EventListener(…) b=new EventSource(…) addXXXListener(l) Event e1 occurs doXXXAction(e1) Event e2 occurs doXXXAction(e2) ….

126. Java GUI Transparency No. 126 Event, listener interface and add-and remove-methods Components supporting this event ActionEvent ActionListener ; addActionListener( ) removeActionListener( ) Button, List, TextField, MenuItem, CheckboxMenuItem, Menu and PopupMenu AdjustmentEvent AdjustmentListener ; addAdjustmentListener( ) removeAdjustmentListener( ) Scrollbar, Anything you create that implements Adjustable ComponentEvent ComponentListener addComponentListener( ) removeComponentListener( ) Component and its derivatives, including Button, Canvas, Checkbox, Choice, Container, Panel, Applet, ScrollPane,Window,Dialog,FileDialog,Frame,L abel,List, Scrollbar, TextArea and TextField

127. Java GUI Transparency No. 127 Event, listener interface and add-and remove-methods Components supporting this event ContainerEvent ContainerListener addContainerListener( ) removeContainerListener( ) Container and its derivatives, including Panel, Applet, ScrollPane, Window, Dialog, FileDialog and Frame FocusEvent FocusListener addFocusListener( ) removeFocusListener( ) Component and its derivatives, including Button, Canvas, Checkbox, Choice, Container, Panel, Applet, ScrollPane, Window, Dialog, FileDialog, Frame Label, List, Scrollbar, TextArea and TextField KeyEvent KeyListener addKeyListener( ) removeKeyListener( ) Component and its derivatives, including Button, Canvas, Checkbox, Choice, Container, Panel, Applet, ScrollPane, Window,Dialog,FileDialog,Frame,Label, List, Scrollbar, TextArea and TextField

128. Java GUI Transparency No. 128 Event, listener interface and add-and remove-methods Components supporting this event MouseEvent (for both clicks and motion) MouseListener; addMouseListener( ) removeMouseListener( ) Component and its derivatives, including Button, Canvas, Checkbox, Choice, Container, Panel, Applet, ScrollPane, Window,Dialog,FileDialog,Frame,Label, List, Scrollbar, TextArea and TextField MouseEvent (for both clicks and motion) MouseMotionEvent MouseMotionListener addMouseMotionListener( ) removeMouseMotionListener( ) Component and its derivatives, including Button, Canvas, Checkbox, Choice, Container, Panel, Applet, ScrollPane, Window,Dialog,FileDialog,Frame,Label, List, Scrollbar, TextArea and TextField WindowEvent WindowListener addWindowListener( ) removeWindowListener( ) Window and its derivatives, including Dialog, FileDialog, Frame, JFrame,

129. Java GUI Transparency No. 129  Event type: ItemEvent listener interface: ItemListener add-and-remove-methods : addItemListener( ), removeItemListener( ) Components supporting this event : Checkbox, CheckboxMenuItem, Choice, List and anything that implements ItemSelectable.  Event type: TextEvent listener interface: TextListener add-and-remove-methods : addTextListener( ), removeTextListener( ) Components supporting this event :Anything derived from TextComponent, including TextArea and TextField

130. Java GUI Transparency No. 130 Subinterfaces of EventListner and their methods  Listener interface/ adapterMethods in interface  ActionListener actionPerformed(ActionEvent)  AdjustmentListeneradjustmentValueChanged(AdjustmentEvent)  ComponentListener, componentHidden(ComponentEvent) ComponentAdaptercomponentShown(ComponentEvent) componentMoved(ComponentEvent) componentResized(ComponentEvent)  ContainerListener, componentAdded(ContainerEvent) ContainerAdapter componentRemoved(ContainerEvent)  FocusListener, focusGained(FocusEvent) // get keyboard FocusAdapter focusLost(FocusEvent) // lost keyboard

131. Java GUI Transparency No. 131 Subinterfaces of EventListner and their methods  Listener interface w/ adapter Methods in interface  KeyListener, keyPressed(KeyEvent) KeyAdapterkeyReleased(KeyEvent) keyTyped(KeyEvent)  MouseListener, mouseClicked(MouseEvent) MouseAdaptermouseEntered(MouseEvent) mouseExited(MouseEvent) mousePressed(MouseEvent) mouseReleased(MouseEvent)  MouseMotionListener, mouseDragged(MouseEvent)  MouseMotionAdapter mouseMoved(MouseEvent)

132. Java GUI Transparency No. 132 Subinterfaces of EventListner and their methods  Listener interface w/ adapter Methods in interface WindowListener, windowOpened(WindowEvent) WindowAdapter windowClosing(WindowEvent) windowClosed(WindowEvent) windowActivated(WindowEvent) windowDeactivated(WindowEvent) windowIconified(WindowEvent) windowDeiconified(WindowEvent)  ItemListener itemStateChanged(ItemEvent)  TextListener textValueChanged(TextEvent)

133. Java GUI Transparency No. 133 And more in Swing:  AncestorListner  CaretListner, CellEditorListner  ChangeListner  HyperlinkListner  InternalFrameListner  ListDataListner  ListSelectionListner  MenuDragMouseListner, MenuKeyListner,,MenuListner  PopupMenuListner  TreeExpansionListner, TreeSelectionListner, TreeWillExpandListner  java.bean.propertyChangeListner, vetoableChangeListner

134. Java GUI Transparency No. 134 JavaBeans  Component programming model  True power in visual programming  Must be able to instantiate, query and configure objects at design time  Java 1.1 reflection provides method and field information on a live object Methods, arguments, return values  Beans specifies a naming convention Identifies design-time fields, event handlers

135. Java GUI Transparency No. 135 What is a Bean?  Just a class (thus easy to learn & use)  Supports three concepts: Properties Events Methods  Follows naming convention to identify these Java call this convention a “design pattern”

136. Java GUI Transparency No. 136 Properties, Methods, Events  For a property named xxxx of type T, create two methods: pubic T getXxxx( ) // capitalize the first char public void setXxxx(T ). (First letter automatically capitalized). boolean property: may also use “is” instead of “get.” boolean isXxxx() Ordinary methods are public  Events use the same “Listeners,” with add- and remove- methods like before  You can create your own event types

137. Java GUI Transparency No. 137 A Simple Bean class Spots {} public class Frog { private int jumps; private Color color; private Spots spots; private boolean jmpr; public int getJumps() { return jumps; } public void setJumps(int js) { jumps = js; } public Color getColor() { return color; } public void setColor(Color c) { color = c; } public Spots getSpots() { return spots; } public void setSpots(Spots newSpots) { spots = newSpots; }

138. Java GUI Transparency No. 138 public boolean isJumper() { return jmpr; } public void setJumper(boolean j) { jmpr = j; } public void addActionListener(ActionListener l) { //... } public void removeActionListener(ActionListener l) { //... } public void addKeyListener(KeyListener l) { //... } public void removeKeyListener(KeyListener l) { //... } // An "ordinary" public method: public void croak() { System.out.println("Ribbet!"); } }

139. Java GUI Transparency No. 139 Introspection  Introspector automatically analyzes a Bean for properties, events & methods

140. Java GUI Transparency No. 140 Summary  “Listener” event model and Beans are a big step forward  Swing is the best UI library I’ve seen  All Swing components are JavaBeans  Numerous application builders use Beans  Beans enable RAD environments  Beans support more sophistication than shown here

141. Java GUI Transparency No. 141 Summary  Java GUI has gone through a lot of design changes  Enough of an intro to get you started  Use a GUI builder for serious development  Other references: “Core Java 2” by Horstmann & Cornell, Prentice-Hall Online help

142. Java GUI Transparency No. 142 Exercises 1.Create an applet with a text field and 3 buttons. When you press each button, make some different text appear in the text field. 2.Add a check box to your applet,capture the event and insert different text into the text field. 3.Add a set of radio buttons which change the text in the text field. 4.Add a menu that changes the text field.

143. Java GUI Transparency No. 143

144. Java GUI Transparency No. 144 More Java topics …  Not detailed: JDBC, RMI, JavaBeans advanced Swing :Jtree, JTable, JText,…  Not covered: Java Security model Internationalization ( i18n, l10n ) Native Methods, Java 2D, Java 3D, Java mulitmedia framework (JMF) XML, JavaMail  J2EE: JDBC, RMI, Servlet and JavaServer page, java IDL (Corba), Java Transaction service (JTS), RMI over IIOP, Java Message Queue(JMQ), JNDI, Enterprise JavaBeans  J2ME: KVM, Configuration: CLDP, profile: MIDP

145. Java GUI Transparency No. 145 J2ME  Java 2 platform targeted at consumer electronics and embedded devices.  consists of a virtual machine ( KVM, thirdParty: Colored KVM, J9 ) and a set of APIs suitable for providing tailored runtime environments for consumer and embedded electronics.  two primary kinds of components Configurations: low-level APIs and optimized virtual machines targeted at two broad categories of devices: 180K ~512K(CLDC: Connection limited device configuration), and 512K+ profile: a specification that details the Java TM technology APIs, built on top of and utilizing the underlying Configuration, necessary to provide a complete runtime environment for a specific kind of device. Known profiles: MIDP (Mobile Information Device profile)