Components and Facilities for Rich Graphical User Interfaces

1
Components and Facilities for Rich Graphical User
Interfaces

• Chapter 7

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Objectives

• Become familiar with the extensive library of GUI
  components offered by the Swing API
• Write code that uses the methods of the
  javax.swing.JComponent class
• Learn to add windows, dialog boxes, and panels to
  a GUI application
• Learn to add labels, buttons, and check boxes to
  a GUI application
• Learn to add menus, toolbars, and actions to a
  GUI application
• Learn to add sliders, spinners, progress bars,
  and scrollbars to a GUI application

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Objectives (Cont.)

• Learn to add lists and combo boxes to a GUI
  application
• Learn to add text-entry components to a GUI
  application
• Learn to add file and color choosers to a GUI
  application
• Learn to add tables and trees to a GUI
  application
• Add printing support to a GUI application using
  the 2D API
• Learn how to discover what print facilities are
  available to an application using the Java Print
  Service API

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Programming with the JFC

• To create applets or application that have
  graphical user interfaces (GUIs), use the Java
  Foundation Classes (JFC) of the Java platform
• Support for the development of GUIs for the Java
  platform is provided by a combination of the AWT
  and Swing APIs

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Packages of the AWT
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Packages of the AWT (Cont.)
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The Swing Packages
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The Swing Packages (Cont.)
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Swing API Components

• Windows
• Dialog boxes
• Panels
• Labels
• Buttons
• Check Boxes
• Menus
• Toolbars
• Sliders

• Spinners
• Progress bars
• Scrollbars
• Lists
• Combo boxes
• Text-entry components
• Tables
• Trees
• File and color choosers

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JComponent Class

• The JComponent class is the abstract superclass
  for all Swing components
• Methods
• void addxxxListener(xxxListener object )
• void repaint( )
• void repaint ( long msec)
• void repaint (int x, int y, int height, int
  width)
• void repaint ( long msec, int x, int y, int
  height, int width)
• void setVisible( boolean b )
• void update( Graphics context )

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Windows, Dialog Boxes, and Panels

• Containers components that hold other components
• Swing provides several top-level container
  components
• JApplet
• JDialog
• JFrame
• JWindow
• To add a component to a JApplet, JDialog, JFrame,
  or JWindow object, call the method getContentPane

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Windows, Dialog Boxes, and Panels (Cont.)

• An application runs in a JFrame object
• An applet runs in a JApplet object
• You build a GUI adding containers and components
  to the JFrame object of an application or the
  panel of an applet
• JDesktopPane, JInternalFrame, JOptionPane, and
  JPanel are lightweight components that extend
  JComponent

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Methods of the Container Class

• The Container class provides several methods for
  adding and removing components or working with
  layouts
• void add( Component comp )
• void add( Component comp, Object constraint )
• Component getComponents()
• LayoutManager getLayout()
• void remove( Component comp )
• void setLayout( LayoutManager mgr )

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Labels, Buttons, and Check Boxes

• Labels add text that typically explains the
  purpose of the other elements of a user interface
• Buttons and check boxes provide the opportunity
  to make selections and trigger actions

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AbstractButton and Its Subclasses
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Menus, Toolbars, and Actions

• To add menus to your GUI, use the classes
• JMenuBar
• JMenuItem
• Jmenu
• JPopupMenu
• JRadioButtonMenuItem
• JCheckBoxMenuItem
• Swing provides support for toolbars through the
  JToolBar class

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Menus, Toolbars, and Actions (Cont.)

• Swing provides a mechanism, the Action interface,
  for defining objects that can be put into
  toolbars and menus
• Actions that are common to both menus and
  toolbars can be created as subclasses of
  AbstractAction to provide a single point of
  control

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Menus, Toolbars, and Actions (Cont.)

• To create a main menu for an application, use a
  JMenuBar object
• Use the add method to add menus to the menu bar
  and the setJMenuBar method to add the menu bar to
  its window
• For a menu that is associated with a component
  and pops up when the user clicks a component,
  create a JPopupMenu object

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Menus, Toolbars, and Actions (Cont.)

• For every item in a menu, use an instance of
  JMenuItem or a subclass of JMenuItem
• To nest menus, use JMenu objects. A JMenu object
  is a JMenuItem object that is itself a menu
• For a menu item that is also a check box, use a
  JCheckBoxMenuItem object
• For a menu item that is also a radio button, use
  a JRadioButtonMenuItem object.

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Menu Classes in javax.swing
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Sliders, Spinners, Progress Bars, and Scrollbars

• JProgressBar, JScrollBar, JSlider, and JSpinner
  allow users to select or display a value within a
  bounded range
• Programs use JProgressBar objects to indicate the
  progress of a long-running operation
• Use a JScrollBar object to control the visible
  contents of a component

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Sliders, Spinners, Progress Bars, and Scrollbars
(Cont.)

• Use a JScrollPane object to display a component
  with contents that are likely to exceed the
  available visible area
• The JScrollPane class adds scrollbars
  automatically to control scrolling operations
• Use a JSlider object to allow selection of a
  value within a bounded range
• Use a JSpinner object to allow selection of a
  value within a bounded range from a predetermined
  list of legal values

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Output of the FontSliderSpinner Class
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Lists and Combo Boxes

• The JComboBox component is a drop-down list that
  is useful for lists with a small number of items
• A JList object displays a list of choices from
  which it is possible to select one or multiple
  items
• JList objects can be contained within JScrollPane
  and scrolled to view the entire list

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Text-Entry Components

• A JEditorPane object is a region that is designed
  to parse and edit specific types of structured
  text content
• A JFormattedTextField object is an entry field in
  which the data that the user enters must meet the
  specified formatting rules
• A JPasswordField field can display a single line
  of text and lets the user enter or edit the text

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Text-Entry Components (Cont.)

• JTextArea is a region that can contain several
  lines of text
• JTextField can display a single line of text and
  lets the user enter or edit the text
• A JTextPane object is a region that can contain
  several lines of text

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TextComponent and Its Subclasses
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Color and File Choosers

• Swing includes the standard classes JFileChooser
  and JColorChooser that implement panels and that
  can be embedded in dialogs or internal frames
• JColorChooser is a panel that allows users to
  browse a palette of available colors and select
  one
• JFileChooser is a panel that allows users to
  browse the contents of the file system and select
  a file to open or a file to save

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Tables and Trees

• Swing provides two sophisticated controls for
  structured information
• JTable
• JTree
• The JTable class is best suited for tabular
  information
• The JTree class is ideal for hierarchical
  information

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Output of the JTree Example Class
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The JTable Constructors

• Table()
• Table(int rows, int columns )
• Table( Object rowData, Object columnNames )
• Table( Vector rowData, Vector columnNames )
• Table( TableModel model )
• Table( TableModel model, TableColumnModel tcModel
  )
• Table( TableModel model, TableColumnModel
  tcModel, ListSelectionModel lsModel )

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The Output of the JTable Class
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Printing with the 2D API

• The Java 2D API introduced the java.awt.print
  package to provide printing support on the Java
  platform
• The java.awt.print.PrinterJob class provides the
  control point for displaying print-related dialog
  boxes, indicating what will print, and actually
  starting the print job
• The PageFormat class provides information about
  the size, orientation, and area available for
  printing for a page of printed output

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java.awt.print.PrinterJob

• Methods of the class java.awt.print.PrinterJob
• PageFormat defaultPage( )
• PrintService getPrintService()
• PageFormat pageDialog( PageFormat format )
• PageFormat pageDialog( PrintRequestAttributeSet
  attrs )
• void print()
• void print( PrintRequestAttributeSet attrs )
• boolean printDialog()
• boolean printDialog( PrintRequestAttributeSet
  attrs )
• void setPrintable( Printable painter )

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The Page Setup Dialog Box
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Java Print Service API

• The Java Print Service API can be used for
  printing text and graphics that are displayed
  within an application
• The Java Print Service API is used to handle many
  flavors of documents, to search and discover
  print services for handling these document flavors

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Java Print Service API (Cont.)

• The Doc interface encapsulates the interface for
  an object that supplies a piece of print data for
  a print job
• The DocFlavor class encapsulates the format in
  which data will be supplied to a DocPrintJob
  object
• The javax.print.DocPrintJob interface represents
  a print job that can print a specified document
  with a set of job attributes

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Summary

• The AWT API provides the infrastructure for
  layout managers, events, event listeners, and
  basic 2D graphics support
• The Swing API provides a comprehensive set of GUI
  components to produce professional applications
• JComponent is the superclass of all Swing
  components, and JApplet, JDialog, JFrame, and
  JWindow are the top-level containers
• An application runs in a JFrame object, and an
  applet runs in a JApplet object

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Summary (Cont.)

• Swing provides classes to support buttons, check
  boxes, menus, toolbars, sliders, spinners,
  progress bars, scrollbars, lists, combo boxes,
  text-entry components
• Swing includes the standard classes JFileChooser
  and JColorChooser that implement panels
• JTable is used for tabular information, and JTree
  for hierarchical information
• Print capability can be added to an application
  by using either the Printing API from the 2D API
  or by using the Java Print Service API