TCU CoSc 10403 Introduction to Programming with Java

1
TCU CoSc 10403 Introduction to Programming (with
Java)

• Java Components

2
Components

• GUI components (widgets) are defined in the Java
  API and are used to provide mechanisms that allow
  a user to interact with an applet. (GUIs)
• Widgets are the parts that are used to build
  graphical user interfaces (e.g. buttons, menus,
  text areas, etc).
• There are two libraries of enhanced graphics
  components that are available to Java
  programmers
• AWT - abstract window toolkit (may have a
  different appearance on different platforms)
• Swing a more modern widget toolkit developed
  to provide a more sophisticated set of GUI
  components. (should look the same across
  different platforms)

3
Visual Guide to Java Swing Components
Borrowed from http//java.sun.com/docs/books/tut
orial/ui/features/components.html
4
Swing vs. AWT

• Swing is built on top of AWT, so you need to
  import AWT and use a few things from it
• Swing is bigger and slower
• Swing is more flexible and better looking
• Swing and AWT are incompatible--you can use
  either, but you cant mix them
• Actually, you can, but its tricky and not worth
  doing
• Basic controls are practically the same in both
• AWT Button b new Button ("OK")
• Swing JButton b new JButton("OK")
• Swing gives far more options for everything
  (buttons with pictures on them, etc.)

5
To build a GUI...

• Make somewhere to display things (a Container)
• Usually you would use a JFrame or a JApplet
• Create some Components (buttons, text areas,
  panels, etc.)
• Its usually best to declare Components as
  instance variables, and
• Define them in your applets init() method or in
  some application method
• Add your Components to your display area
• Choose a layout manager
• Add your Components to your JFrame or JApplet
  according to the rules for your layout manager
• Attach Listeners to your Components
• Interacting with a Component causes an Event to
  occur
• A Listener gets a message when an interesting
  event occurs, and executes some code to deal with
  it

6
Containers and Components

• A GUI is built by putting components into
  containers
• The job of a Container is to hold and display
  Components
• Some frequently used types (subclasses) of
  Component are JButton, JCheckbox, JLabel,
  JTextField, and JTextArea
• A Container is also a Component
• This allows Containers to be nested
• Important Container classes are JFrame, JApplet,
  and JPanel
• JFrame and JApplet both contain other containers
  (container hierarchy)
• You typically create and use JPanels directly

7
To create an applet

• public class MyApplet extends JApplet
• The only way to make an applet is to extend
  Applet or JApplet
• You can add components to the applet
• The best place to add components is in init()
• You can paint directly on the applet, but
• its better to paint on a contained component
• Do all painting from paint(Graphics g)

8
Swing Components

• Adding components to an applet is like adding
  magnets to the fridge easy to move around.
  Writing in the paint()method using drawString is
  like finger painting your fridge permanently
  placed.
• Components (widgets) will appear behind strings
  or graphics objects that are drawn on the screen
  using paint.
• In order to have access to the Swing components
  youll need to use the command
• import javax.swing.

9
Example of relationship between paint()and init()
methods

• import javax.swing.
• import java.awt.
• public class PaintAndInitMethodsDemo extends
  JApplet
• Font f1
• Color c1, c2
• JButton b1
• public void init()
• setLayout(new FlowLayout())
• f1 new Font("Serif",Font.BOLD, 40)
• c1 Color.RED
• c2 Color.BLUE
• b1 new JButton("COSC 10403")
• add(b1)
• b1.setForeground(c2)

Paint method draws on top of components managed
by the layout manager for Japplet opposite for
Applets
10
Component Class

• Widgets are derived from the Component class
  (which is itself defined in the java.awt package)
• The most important class in the java.awt package.
• It is also the largest, having 129 methods (at
  present).
• It is the parent(super) class for all the Java
  widget classes and serves as the repository of
  all the methods that are common to the widgets
  (it is an abstract class and does not need to be
  instantiated).
• Hierarchy

11
A JApplet is a Panel is a Container
java.lang.Object java.awt.Component
java.awt.Container
java.awt.Panel
java.applet.Applet
javax.swing.JApplet
so you can display things in an Applet
12
Introduction to GUI Components

• Consider this simple program for creating Jlabels
  for displaying text on an applet

import javax.swing. import java.awt. public
class LabelDemo extends JApplet JLabel l1
new Jlabel() JLabel l2, l3 public void
init() setLayout(new FlowLayout())
//default layout is BorderLayout.CENTER l2
new JLabel("Texas Christian University") l3
new JLabel("Fall, 2009")
add(l1) l1.setText(CoSc 10403)
add(l2) add(l3)
Note that components appear on the applet,
centered, top-down, left-to-right in the order
that they were added to the applet this is
FlowLayout. The default layout is
BorderLayout.CENTER
13
The JLabel Class

• Labels allow the user to create GUI components
  that can display un-selectable text or images.
• Constructors (6 ways to build a JLabel)
• JLabel() - Creates a JLabel instance with no
  image and with an empty string for the title.
• JLabel(String text) - Creates a JLabel instance
  with the specified text.
• JLabel(String text, int horizontalAlignment)
  - Creates a JLabel instance with the specified
  text and horizontal alignment.
• JLabel(Icon image) - Creates a JLabel instance
  with the specified image.
• JLabel(Icon image, int horizontalAlignment)
  - Creates a JLabel instance with the specified
  image and horizontal alignment.
• JLabel(String text, Icon icon, int horizontalAlign
  ment)  -  Creates a JLabel instance with the
  specified text, image, and horizontal alignment.

14
JLabels
import java.awt. import javax.swing. public
class LabelDemo extends JApplet JLabel l1
new JLabel("COSC 10403") JLabel l2 new
JLabel("Texas Christian University",
JLabel.RIGHT) JLabel l3 public void
init() setLayout(new FlowLayout()) add(l1
) add(l2) l3 new JLabel("Fall, 2009",
JLabel.LEFT) add(l3)
15
JLabels (continued)

• By specifying HTML code in a JLabel's text, you
  can give the label various characteristics such
  as multiple lines, multiple fonts or multiple
  colors.
• If the label uses just a single color or font,
  you can avoid the overhead of HTML processing by
  using the setForeground or setFont method
  instead.

import javax.swing. import java.awt. public
class LabelStyles extends JApplet JLabel
l1 JLabel l2 JLabel l3 Font f1 public
void init() setLayout(new FlowLayout())
//default is BorderLayout.CENTER l1 new
JLabel("CoSc 10403 - Introduction to Computer
Science") l1.setForeground(Color.RED) l2
new JLabel("Texas Christian University") f1
new Font("Serif",Font.BOLDFont.ITALIC,15) l2.s
etFont(f1) l3 new JLabel("lthtmlgtltfont
colorBLUEgt Fall,lt/fontgt " "ltbgt semester lt/bgt"
"ltigt2009lt/igt") add(l1) add(l2) add(l3)

16
import javax.swing. import java.awt. public
class JLabelImageDemo extends JApplet Image
img1, img2, img3, img4, img5 ImageIcon ic1,
ic2, ic3, ic4, ic5 JLabel l1, l2, l3, l4,
l5 public void init ( )
setLayout( new FlowLayout( ) ) img1
getImage( getCodeBase( ), "Pics/Elf.gif" )
img2 getImage( getCodeBase( ),
"Pics/ElfBox.gif" ) img3 getImage(
getCodeBase( ), "Pics/Santa.gif" ) img4
getImage( getCodeBase( ), "Pics/Computer.gif" )
img5 getImage( getCodeBase(),
"Pics/Seesaw.gif") // can't just add images
like this add( image ) ic1 new
ImageIcon( img1 ) ic2 new ImageIcon(
img2 ) ic3 new ImageIcon( img3 )
ic4 new ImageIcon( img4 ) ic5 new
ImageIcon( img5 ) // can't just add
ImageIcons like this add( imageIcon ) l1
new JLabel( ic1 )// have to add to a JLabel
// now can add the Jlabel to the applet l2
new JLabel("Elf with Box",ic2,JLabel.CENTER)
l2.setHorizontalTextPosition(JLabel.LEFT)
l3 new JLabel("Santa",ic3,JLabel.RIGHT)
l4 new JLabel("Computer",ic4,JLabel.CENTER
) l4.setHorizontalTextPosition(JLabel.CENTER)
l4.setVerticalTextPosition(JLabel.BOTTOM)
l5 new JLabel("Seesaw",ic5,JLabel.LEFT)
l5.setHorizontalTextPosition(JLabel.CENTER)
add(l1) add(l2) add(l3)
add(l4) add(l5)
Text position can be managed with setHorizontalT
extPosition(pos) setVerticalTextPosition(pos) Whe
re pos can be one of Horizontal
Vertical JLabel.LEFT JLabel.TOP JLabel.CENTER JLab
el.CENTER JLabel.RIGHT JLabel.BOTTOM
17
The JButton Class

• A single button set up to initiate some action
  when pushed by the user.
• Note A Swing button can display both text and an
  image.
• Four Constructors that we will use
• Jbutton() - creates a button with no set text
  or icon
• Jbutton(String text) - creates a button with
  text
• Jbutton(Icon icon) - creates a button with an
  icon
• Jbutton(String text, Icon icon)- creates a button
  with initial text and an icon.

18
JButtons

• Swing permits
• Text
• JButton mybutton
• mybutton new JButton( Hello World )
• Image
• JButton mybutton
• mybutton new JButton( ImageIconVariable )
• Text and image
• JButton mybutton
• mybutton new JButton(three, ImageIconVariable
  )
• Text overlayed on top of image
• JButton mybutton
• mybutton new JButton( text w/ image,
  ImageIconVariable ) mybutton.setHorizontalTextPo
  sition(JButton.CENTER)

19
JButton Demo

• import java.awt.
• import javax.swing.
• public class JButtonDemo extends JApplet
• JButton b1, b2, b3, b4, b5, b6
• Image img1, img2
• ImageIcon icon
• public void init()
• setLayout(new FlowLayout())
• b1 new JButton("Press")
• img1 getImage(getCodeBase(),"Pics/Earth.jpg")
  
• icon new ImageIcon( img1 )
• b2 new JButton( icon )
• img2 getImage( getCodeBase(),
  "Pics/Mars.jpg)

20
JButton Example font, color, center

• import javax.swing.
• import java.awt.
• public class JButtonImg2 extends JApplet
• JButton one, two,three
• Image img
• ImageIcon icon
• public void init( )
• setLayout( new FlowLayout( ) )
• one new JButton( "one" )
• one.setForeground( Color.red ) // change
  color to red
• img getImage( getCodeBase( ),
  "buttonPoland.png" )
• icon new ImageIcon( img )
• two new JButton( icon )

21
Textual Widgets

• Swing provides six text components that deal with
  the display of text (only three are discussed in
  our text)
• JTextField, JPasswordField, and JTextArea.
• A JTextField looks like a box into which the user
  can enter a single line of text. It might be used
  to collect personal information about a user.(it
  can be changed by the user by clicking and
  dragging or by the program using the proper
  methods).
• A JTextArea provides space for more than a single
  line of input or output. It might be used to
  allow a user to add personal comments.
• A JPasswordField provides specialized text fields
  for password entry (for security reasons, a
  password field does not show the characters that
  the user types)

22
The JTextField Class

• A GUI component that displays a single line of
  text. Under program control it is possible to
  specify whether or not the user is allowed to
  edit the contents of the field. Because they may
  be edited, a JTextField can be used to obtain
  input from the user.
• Four Constructors that we will use for building
  JTextFields
• JTextField() constructs a new JTextField.
• JTextField(int columns) constructs a new empty
  JTextField with the specified number of columns.
• JTextField(String text) constructs a new
  JTextField initialized with the specified text.
• JTextField(String text, int columns) constructs
  a new JTextField initialized with the specified
  text and columns.

23
JTextField Demo Program

• import java.awt.
• import javax.swing.
• public class JTextFieldDemo1 extends JApplet
• JTextField tf1, tf2, tf3, tf4, tf5
• JPasswordField jpwf1
• Font f1 new Font("Serif",Font.ITALIC,15)
• JLabel l1
• public void init()
• setLayout(new FlowLayout())
• tf1 new JTextField() //default size
• tf2 new JTextField(10)
• tf2.setHorizontalAlignment(JTextField.RIGHT)

24
The JTextArea Class

• A JTextArea is similar to a JTextField except
  that it lets you view and edit multiple lines of
  text. Its size can be specified when the object
  is instantiated.
• Text can be appended, inserted, or replaced at
  any location (using click and drag).
• Scrollbars may be attached (using a JScrollPane)
  along the bottom and right side of the text area,
  no matter how much text is actually contained in
  it. The scrollbars can be used to bring desired
  portions of the text into the visible area.
• A JTextArea is defined by the JTextArea class, a
  subclass of the JTextComponent class, which
  contains several methods of its own.
• JTextArea has a bound property for line wrapping
  that controls whether or not it will wrap lines.
  By default, the line wrapping property is set to
  false (not wrapped).

25
JTextArea Constructors

• There are four constructors that we will use in
  the class
• JTextArea() -
• Constructs a new JTextArea
• JTextArea(int rows, int columns)
• Constructs a new empty JTextArea with the
  specified number of rows and columns.
• JTextArea(String text)
• Constructs a new JTextArea with the specified
  text displayed.
• JTextArea(String text, int rows, int columns)
• Constructs a new JTextArea with the specified
  text and number of rows and columns.

26
JTextArea Demo

• import javax.swing.
• import java.awt.
• public class JTextAreaDemo extends JApplet
• JTextArea ta1, ta2, ta3, ta4, ta5, ta6, ta7
• JScrollPane jsp
• public void init()
• ta1 new JTextArea ( )
• //creates a JTextArea with 0 columns, 0 rows
• ta2 new JTextArea ( 3, 10 )
• //line wrapping is not enabled
• ta3 new JTextArea ( 3, 10 )
• ta3.setLineWrap(true)
• //line wrapping is enabled within the column
  width specified
• ta4 new JTextArea ( 3, 10 )
• ta4.setLineWrap(true)

27
Active Widgets

• The Swing package supports a variety of window
  components that the user can interact with to
  initiate an action.
• Javax.swing supports four distinct types of
  components, each serving a different purpose
  and each is used in specific situations
• JCheckBox Class
• A component that can be selected or deselected
  and which displays its state to the user. Often
  a group of checkbox buttons are used to define a
  set of options. Multiple options can be chosen
  at the same time.
• 2. JRadioButton Class
• A single component that displays a list of
  choices when pushed. The current choice is shown
  next to the button at all times but only a single
  button can be chosen at one time.
• 3. JComboBox Class
• A single component that displays a list of
  choices when pushed. The current choice is shown
  next to the button at all times.
• 4. Jlist Class
• A component that allows the user to select one
  or more objects from a list.

28
The JCheckBox Class

• Seven Constructors that we will use
• JCheckBox()
• Creates an initially unselected check box button
  with no text and no icon.
• JCheckBox(String s)
• Creates a Checkbox with the given label and
  unchecked (false) state.
• JCheckBox(String s, boolean b)
•  Creates a check box with text and specifies
  whether or not it is initially selected.
• JCheckBox(Icon icon)
• Creates an initially unselected check box with
  an icon.
• JCheckBox(Icon icon, boolean selected)
• Creates a check box with an icon and specifies
  whether or not it is initially selected.
• JCheckBox(String s, Icon icon)
• Creates an initially unselected check box with
  the specified text and icon.

29
JCheckBox Demo

• import java.awt.
• import javax.swing.
• public class JCheckBoxDemo extends JApplet
• JCheckBox cb1, cb2, cb3, cb4, cb5
• Image img1
• ImageIcon imgIcon1
• //Images for the selected state and unselected
  state
• Image notSelRedImg, selPaleRedImg
• //ImageIcons for the selected state and
  unselected state
• ImageIcon notSelRedImgIcon, selPaleRedImgIcon
• public void init()
• setLayout(new FlowLayout())

30
JRadioButton Class

• An implementation of a radio button -- an item
  that can be selected or deselected, and which
  displays its state to the user.
• Seven Constructors that we will use
• JRadioButton()
• Creates an initially unselected radio button
  with no set text.
• JRadioButton(String, text)
• Creates an unselected radio button with the
  specified text.
• JRadioButton(String text, boolean selected)
• Creates a radio button with the specified text
  and selection state.
• JRadioButton( Icon icon)
• Creates an initially unselected radio button
  with the specified image but no text.
• JRadioButton(Icon icon, boolean selected)
• Creates a radio button with the specified image
  and selection state, but no text.

31
JRadioButton Demo

• import java.awt.
• import javax.swing.
• public class JRadioButtonDemo extends JApplet
• JRadioButton blankRadioButton, onCampus,
  offCampus, male, female
• ButtonGroup housingGroup, genderGroup
• public void init( )
• blankRadioButton new JRadioButton()
• onCampus new JRadioButton( "Lives on Campus"
  )
• offCampus new JRadioButton( "Lives off
  Campus" )
• male new JRadioButton( "Male" , true)
• female new JRadioButton( "Female" )
• housingGroup new ButtonGroup( )
• genderGroup new ButtonGroup()

32
JRadioButton Demo

• import java.awt.
• import javax.swing.
• public class JRadioButtonDemo1 extends JApplet
• JRadioButton male, female
• ButtonGroup genderGroup
• //Images for the selected state and unselected
  state
• Image notSelMaleImg, selMaleImg,
  notSelFemaleImg, selFemaleImg
• //ImageIcons for the selected state and
  unselected state
• ImageIcon notSelMaleImgIcon, selMaleImgIcon,
  notSelFemaleImgIcon, selFemaleImgIcon
• public void init( )
• notSelMaleImg getImage(getCodeBase(),
  "Pics/Male.png")
• selMaleImg getImage(getCodeBase(),
  "Pics/SelectedMale.png")
• notSelFemaleImg getImage(getCodeBase(),
  "Pics/Female.png")
• selFemaleImg getImage(getCodeBase(),
  "Pics/SelectedFemale.png")

Automatically selected.
33
JComboBox Class

• A component that combines a button or editable
  field and a drop-down list. Scrollbars are
  automatically added to the drop-down list if
  about seven or more items are in the list (this
  number may be modified by using the
  setPreferredSize method).
• One Constructor that we will use
• JComboBox()
• Creates a JComboBox with a default data model.

34
JComboBox Demo

• import javax.swing.
• import java.awt.
• public class JComboBoxDemo extends JApplet
• JComboBox majors
• public void init( )
• majors new JComboBox( )
• majors.addItem( "Select One Of" )
• majors.addItem( "Computer Science" )
• majors.addItem( "Mathematics" )
• majors.addItem( "Physics" )
• majors.addItem( "Engineering" )
• majors.addItem( "Geology" )
• setLayout( new FlowLayout( ) )
• add( majors )

35
The List Class (from AWT)

• A component that allows the user to select one or
  more objects from a list - somewhat like a
  permanently expanded JComboBox. The JList class
  is intuitively more difficult to understand than
  the analogous List class in AWT. Consequently,
  we will use the AWT List component in this
  course.
• Appears as a component with a collection of
  items, one per line.
• Example
• Note
• When the mouse is clicked on one of the lines, it
  becomes highlighted and serves as the current
  selection.
• (2) A List object may behave in one of two ways.
  
• clicking on an item may turn off any currently
  highlighted rows (the single selection mode).
• clicking on an item may highlight it without
  influencing any of the other already highlighted
  rows (the multiple-selection mode). A shift-click
  operation.

36
The List Class
import java.awt. import java.applet. public
class ListDemoProgram extends Applet List l1
new List() List l2 new List(6) List l3
new List(5, true) public void init()
add(l1) add(l2) add(l3) l3.add("RO
TC") l3.add("Honor's Program") l3.add("Ban
d") l3.add("Student Government") l3.add("A
thletics")

• Three Constructors
• List()
• Creates a default-sized List object in
  single-selection mode.
• List(int rows)
• Creates a List object in single-selection mode
  with the specified number of rows.
• List(int r, boolean b)
• Creates a List object with the specified number
  of rows, and if the argument is false, the
  created List is in single-selection mode.
• Must use methods
• void add(String item)
• Adds a new item (to the bottom of the list) with
  the given label to this List object.
• void add(String s, int i)
• Adds a new item (in the position indicated by
  index) with the given label to this List object.
  Items are shifted down to make room for the new
  entry.

37
Some Useful Methods in the JLabel Class

• void setText (String text) Sets the text of the
  specified Label to that given in the argument.
• Example
• blanklabel.setText(Now something)
• String getText() Returns a String object whose
  value is the same as that of this JLabels
  text.
• Example
• String str blanklabel.getText()
• Alignment methods
• int getHorizontalAlignment()int
  getVerticalAlignment()
• void setHorizontalAlighment(int alignment)
• void setVerticalAlignment(int alignment)
• Icon getIcon (String text) Returns the graphic
  image that the label displays.
• void setIcon (Icon icon) Defines the icon this
  component will display.

38
Useful Methods in the JButton class

• void setText (String s)Sets the JButtons label
  to be the specified string.
• Example
• cancelB.setText(Cancel)
• String getText()Gets the label of the specified
  Jbutton.
• Example
• String s b1.getText()
• void setActionCommand (String s)Sets command
  name for action event fired by this Jbutton.
• Example
• JButton b1 new JButton(Cancel)
• b1.setActionCommand(B1)
• String getActionCommand()Returns the command
  name of the action event fired by this
  JButton.
• Example
• String str
• str b1.getActionCommand()

39
Commonly used TextField TextArea Methods

• TextFields
• void setColumns(int columns)
• sets the width of this JTextField to be enough
  to hold columns characters (must be gt zero)
• int getColumns()
• returns the current width, in columns, of this
  JTextField.
• String getSelectedText()
• returns the selected text in this JTextField.
• String getText()
• returns the contents of the JTextField.
• void setText(String string)
• set the contents of the JTextField to the
  specified argument.
• TextAreas
• int getColumns()
• returns the current width, in columns, of this
  JTextArea.
• int getRows()
• returns the current height, in rowes, of this
  JTextArea.
• void append(String str)

40
Commonly used TextComponent Methods

• TextComponent
• String getSelectedText()
• returns the text that has been selected in this
  text component.
• String getText()
• returns the text that is in this text component.
• void setText(String s)
• Sets the text in this text component to the
  string provided.
• void setEditable(boolean b)
• Sets the flag that determines whether this text
  component can be changed.

41
Some JComboBox Methods

• void add(String item) already seen!!!
• Adds a new item with the given label to the list
  of this JComboBox object.
• int getItemCount()
• Returns the number of items currently in this
  JComboBox object.
• String getItemAt(int index)
• Returns the text of the item that is currently in
  the index position.
• int getSelectedIndex()
• Returns the index of the currently selected item.
• String getSelectedItem()
• Returns the text of the currently selected item.
• void insertAt(String item, int index) already
  seen!!!
• Inserts a new item string in the list in the
  given index position.
• void remove(int index)

42
Some Useful JCheckBox JRadioButton Methods

• JCheckBox
• void setText(String label)
• Sets the label of this JCheckBox.
• String getText(String label)
• Returns a string containing the label text of
  this JCheckBox.
• boolean getState()
• Returns the current state (true or false) of
  this JCheckBox.
• void setSelected(boolean state)
• Sets the current state of this JCheckBox.
• void setSelectedIcon(Image image)
• Sets the selected icon for the JCheckBox
• JRadioButton
• Icon getSelectedIcon()

43
Some Useful List Methods

• void delItems(int start, int end) //Removes a
  inclusive range of items from the List.
• void deselect(int index) //Turns off the
  selection of the item in position index.
• String getItem(int index) //Returns the text of
  the item in position index in the List.
• int getItemCount() //Returns the number of
  items in the List.
• int getRows() //Returns the number of rows in
  this List item.
• int getSelectedIndex() //Returns the index of
  the current selection (-1 if none).
• boolean isMultipleMode()
• Returns true if this List is in
  multiple-selection mode (else false).
• void remove(int index)
• Remove the item at the given index from the List.
• void remove(String item)
• Removes the item with the given string from the
  List.
• void removeAll()
• Removes all items from the List.
• void replaceItem(String newItem, int index)
• Replaces the item in position index with the text
  given by the argument.
• void select(int index)
• Selects the item in position index.
• void setMultipleMode(boolean m)

44
Some Other Useful Methods

• void setVisible(boolean b) // makes the current
  component visible or not.
• void setEnabled(boolean b) // makes the current
  component visible or not.
• void setEditable(boolean b) // makes the current
  component editable or not.
• void setForeground(Color c) // sets the
  Foreground color of the object to the specified
  value.
• void setBackground(Color c) // sets the
  Background color of the object to the specified
  value.
• void requestFocus() // requests that this
  component gets the input focus
• void validate() // ensures that the
  component has a valid layout.

45
How do the paint()and init() methods relate?

• import java.awt.
• import javax.swing.
• public class PaintMethodDemo extends JApplet
• int i 0
• List l new List(5)
• JComboBox c new JComboBox()
• public void init()
• setLayout(new FlowLayout())
• add(c)
• add(l)
• public void paint(Graphics g)
• i i 1

Note new values are added to each Component
every time the applet window size changes.