CS 596 Java Programming Fall Semester, 1998 Fonts, Components, Dialogs
	To Lecture Notes Index © 1998, All Rights Reserved, SDSU & Roger Whitney San Diego State University -- This page last updated 21-Dec-98

Reference:

Fonts
Components

Label
Button
Checkbox
Checkbox Groups - Radio buttons
Choice - Drop-down Lists
List
TextArea
TextField
ScrollPane

Dialogs

FileDialog

Reference:

Q-dec3 3mins Doc 31, Fonts, Components, Dialogs Slide # 2

Fonts

import  java.awt.*;
class  FancyHello  extends  Frame  {
   public  FancyHello() {
      int  pointSize  =  36;
      setFont( new Font( "TimesRoman", Font.BOLD, pointSize ));
      setBackground( Color.white );
      setTitle( "Hi Mom" );
      setSize( 150,  150);
      show();
   }
   public  void  paint(  Graphics  display  ){
      int x  =  50;
      int y  =  60;
      display.setColor( Color.black );
      display.drawString(  "Hello", x, y );
      display.setFont( new Font("Symbol", Font.ITALIC, 12 ));
      x  =  50;
      y  =  100;
      display.drawString(  "World", x, y );
   }
   public  static  void  main( String  args[] ){
      new  FancyHello();
   }
}
Doc 31, Fonts, Components, Dialogs Slide # 3

Q-dec3 3mins, Q-dec3 3mins Doc 31, Fonts, Components, Dialogs Slide # 4

import  java.awt.Toolkit;
class  WhatFonts {
   public  static  void  main( String  args[] ) {
      Toolkit  platformInfo = Toolkit.getDefaultToolkit();
      String[] availbleFonts = platformInfo.getFontList();
      for ( int index = 0; index < availbleFonts.length; index++ )
         System.out.println( availbleFonts[ index ]  );
   }
}

new Font("Courier", Font.ITALIC + Font.BOLD, 12 )
Doc 31, Fonts, Components, Dialogs Slide # 5

import  java.awt.*;
class  TextSize  extends  Frame  {
   public  TextSize() {
      setTitle( "Text Size" );
      setSize( 300,  200);
      show();
   }
   public  void  paint(  Graphics  display  ){
      Font largeText = new Font( "TimesRoman", Font.BOLD, 24 );
      FontMetrics  largeTextSize;
      largeTextSize = display.getFontMetrics( largeText );
      display.setFont( largeText  );
      display.setColor( Color.black );
      int x  =  50;
      int y  =  90;
      display.drawString(  "Hello ", x, y );
      x = x + largeTextSize.stringWidth( "Hello " );
      display.drawString(  "World", x, y );
   }
   public  static  void  main( String  args[] ) {
      new  TextSize();
   }
}
Doc 31, Fonts, Components, Dialogs Slide # 6

Doc 31, Fonts, Components, Dialogs Slide # 7

Components

Doc 31, Fonts, Components, Dialogs Slide # 8

Doc 31, Fonts, Components, Dialogs Slide # 9

Label

Constructs an empty label.

Constructs a new label with the specified String of text.

Constructs a new label with the specified String of text and the specified alignment.

Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 10

class  LabelExample  extends Frame  {
      
   public LabelExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Label Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new GridLayout(5, 1) );
      
      add( new Label( "Hi Mom" ) );
      add( new Label( "Hi Dad", Label.CENTER  ) );
      add( new Label( "Good Bye", Label.RIGHT ) );
      add( new Label( "Good Luck", Label.LEFT ) );
      Font largeFont = new Font( "TimesRoman", Font.ITALIC, 24 );
      Label largeText = new Label( "Large Font" );
      largeText.setFont( largeFont );
      add( largeText );
      show();
   }   
   
   public  static  void  main( String  args[] ) {
      new  LabelExample(150, 100);
   }
}

Doc 31, Fonts, Components, Dialogs Slide # 11

Button

class  ButtonTextExample  extends Frame  {
      
   public ButtonTextExample( int widthInPixels, int heightInPixels) {
      setTitle( "Button Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      Font largeFont = new Font( "TimesRoman", Font.ITALIC, 24 );
      Button largeText = new Button( "Large Font" );
      largeText.setFont( largeFont );
      add( largeText );
      show();
   }   
   
   public  static  void  main( String  args[] ) {
      new  ButtonTextExample(150, 100);
   }
}

Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 12

Checkbox

Constructs a Checkbox with no label, no Checkbox group, and initialized to a false state.

Constructs a Checkbox with the specified label, no Checkbox group, and initialized to a false state.

Constructs a Checkbox with the specified label, specified Checkbox group, and specified boolean state.

Q-dec3 1min Doc 31, Fonts, Components, Dialogs Slide # 13

import java.awt.*;
import java.awt.event.*;
class CheckboxExample extends Frame {
   private Checkbox left = new Checkbox( "Left" );
   private Checkbox right = new Checkbox( "Right" );
      
   public CheckboxExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Checkbox Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( left );
      add( right );
      left.addItemListener( new LeftRightListener() );
      right.addItemListener( new LeftRightListener() );
      show();
   }
   private void reportChange( Checkbox selectedBox ) {
      System.out.print( selectedBox.getLabel() + " box changed " );
      System.out.println( "value is " + selectedBox.getState() ); 
   }
   class LeftRightListener implements ItemListener {
      public void itemStateChanged( ItemEvent event ) {
         System.out.println( "GetItemSelectable: " + event.getItemSelectable() );
         System.out.println( "GetItem: " + event.getItem() );
         if ( event.getStateChange() == ItemEvent.SELECTED )
            System.out.println( "Selected" );
         else
            System.out.println( "Deselected" );
         reportChange( (Checkbox) event.getItemSelectable() );
      }
   }
Q-dec3 1min Doc 31, Fonts, Components, Dialogs Slide # 14

   public  static  void  main( String  args[] ) { 
      new  CheckboxExample(200, 50);
   }
}

Doc 31, Fonts, Components, Dialogs Slide # 15

import java.awt.*;
import java.awt.event.*;
class  CheckboxToggleExample  extends Frame  {
   private Checkbox toggle = new Checkbox( "Off");
      
   public CheckboxToggleExample( int  widthInPixels, 
                                       int heightInPixels ) {
      setTitle( "Toggle Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( toggle );
      toggle.addItemListener( new ToggleListener() );
      show();
   }
   class ToggleListener implements ItemListener {
      public void itemStateChanged( ItemEvent event ) {
         Checkbox selected = (Checkbox) event.getItemSelectable();
         if ( selected.getState() == true )
            selected.setLabel( "On" );
         else if  ( selected.getState() == false )
            selected.setLabel( "Off" );
      }
   }
      
   public  static  void  main( String  args[] ){
      new  CheckboxToggleExample(200, 50);
   }
}
Doc 31, Fonts, Components, Dialogs Slide # 16

Q-dec3 37secs Doc 31, Fonts, Components, Dialogs Slide # 17

Checkbox Groups - Radio buttons

import java.awt.*;
import java.awt.event.*;
class  RadioButton  extends Frame  {
   public RadioButton( int  widthInPixels, int heightInPixels ) {
      setTitle( "Radio Button Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      CheckboxGroup directions = new CheckboxGroup();
      add( new Checkbox( "Left", directions, false) );
      add( new Checkbox( "Right", directions, true));
      show( );
   }
   public  static  void  main( String  args[] ) {
      new  RadioButton(200, 50);
   }
}

getSelectedCheckbox() 
setSelectedCheckbox(Checkbox) 
toString()
Q-dec3 44secs Doc 31, Fonts, Components, Dialogs Slide # 18

Choice - Drop-down Lists

Q-dec3 5mins, Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 19

import java.awt.*;
import java.awt.event.*;
class  ChoiceBoxes  extends Frame  {
   Choice directions = new Choice();
   
   public ChoiceBoxes( int  widthInPixels, int heightInPixels ) {
      setTitle( "ChoiceBox Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      directions.addItem( "Left" );
      directions.addItem( "Right" );
      directions.addItem( "Up" );
      directions.addItem( "Down" );
      directions.addItemListener( new ChoiceListener() );
      add( directions );
      show();
   }
   class ChoiceListener implements ItemListener {
      int  count = 1;
      public void itemStateChanged( ItemEvent event ) {
         Choice selected = (Choice) event.getItemSelectable();
         int selectedIndex = selected.getSelectedIndex();
         String selectedText = selected.getSelectedItem();
         System.out.println( "Selected index: " +  selectedIndex);
         System.out.println( "Selected string: " + selectedText );
         selected.insert( String.valueOf( count++ ), selectedIndex );
         selected.remove( selectedText );
      }
   }
   public  static  void  main( String  args[] ) { new  ChoiceBoxes(200, 200); }
}
Doc 31, Fonts, Components, Dialogs Slide # 20

Q-dec3 39secs Doc 31, Fonts, Components, Dialogs Slide # 21

List

Creates a new scrolling list initialized with no visible Lines or multiple selections.

Creates a new scrolling list initialized with the specified number of visible lines and a boolean stating whether multiple selections are allowed or not.

Q-dec3 1min Doc 31, Fonts, Components, Dialogs Slide # 22

import java.awt.*;
import java.awt.event.*;
class  ListExample  extends Frame  {
   public ListExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "List Box Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      boolean areMultipleSelectionsAllowed = false;
      int numberDisplayed = 4;
      List directions = new List( numberDisplayed, 
                        areMultipleSelectionsAllowed );
      directions.addItem( "Left" );
      directions.addItem( "Right" );
      directions.addItem( "Up" );
      directions.addItem( "Down" );
      directions.addItemListener( new ListListener() );
      add( directions );
      show();
   }
Q-dec3 3mins Doc 31, Fonts, Components, Dialogs Slide # 23

   class ListListener implements ItemListener {
      public void itemStateChanged( ItemEvent event ) {
         List selected = (List) event.getItemSelectable();
         int selectedIndex = selected.getSelectedIndex();
         String selectedText = selected.getSelectedItem();
         System.out.println( "Selected index: " +  selectedIndex);
         System.out.println( "Selected string: " + selectedText );
      }
   }
   public  static  void  main( String  args[] ) {
      new  ListExample(200, 100);
   }
}

Q-dec3 2mins, Q-dec3 4mins Doc 31, Fonts, Components, Dialogs Slide # 24

TextArea

Constructs a new TextArea.

Constructs a new TextArea with the specified number of rows and columns.

Constructs a new TextArea with the specified text displayed.

Constructs a new TextArea with the specified text and number of rows and columns.

addNotify() 
append(String) 
getColumns() 
getMinimumSize() 
getMinimumSize(int, int) 
getPreferredSize() 
getPreferredSize(int, int) 

getRows() 
getScrollbarVisibility() 
insert(String, int) 
paramString() 
replaceRange(String, int, int) 
setColumns(int) 
setRows(int) 

Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 25

import java.awt.*;
import java.awt.event.*;
class  TextAreas  extends Frame  {
   TextArea userInput;
   Button done = new Button( "Done Typing" );
      
   public TextAreas( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Area Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      int numberOfLines = 3;
      int numberOfColumns = 30;
      userInput = new TextArea( numberOfLines, numberOfColumns );
      add( userInput );
      add( done );
      
      done.addActionListener( new ActionListener() {
            public void actionPerformed( ActionEvent event ) {
               checkUserInput();
            }
         });
      show();
   }
   
   private void checkUserInput() {
      System.out.println( "You typed: " +  userInput.getText() );
      System.out.println( "Selected text>" + 
                         userInput.getSelectedText() +"<" );
      userInput.setText( "Hi Mom");
   }
   public  static  void  main( String  args[] ) {
      new  TextAreas(300, 150);
   }
}
Q-dec3 48secs Doc 31, Fonts, Components, Dialogs Slide # 26

Doc 31, Fonts, Components, Dialogs Slide # 27

TextField

Constructs a new TextField.

Constructs a new TextField initialized with the specified columns.

Constructs a new TextField initialized with the specified text.

Constructs a new TextField initialized with the specified text and columns.

addActionListener(ActionListener)
removeActionListener(ActionListener)  
addNotify() 
echoCharIsSet() 
getColumns() 
getEchoChar() 
getMinimumSize() 

getMinimumSize(int) getPreferredSize() 
getPreferredSize(int) 
paramString() 
setColumns(int) 
setEchoChar(char) 

Doc 31, Fonts, Components, Dialogs Slide # 28

class  TextFieldExample  extends Frame  {
   TextField firstName;
   TextField lastName;
   Button done = new Button( "Done Typing" );
      
   public TextFieldExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Field Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new GridLayout(3, 1) );
      
      int numberOfColumns = 10;
      firstName = new TextField(  numberOfColumns );
      Panel first = new Panel( new FlowLayout() );
      first.add( new Label( "First name", Label.RIGHT ));
      first.add( firstName );
      
      lastName = new TextField(  numberOfColumns );
      Panel last = new Panel( new FlowLayout() );
      last.add( new Label( "Last name", Label.RIGHT ) );
      last.add( lastName );
      
      Panel buttons = 
         new Panel( new FlowLayout( FlowLayout.CENTER));
      buttons.add( done );
      
      add( first );
      add( last );
      add( buttons );
      
Doc 31, Fonts, Components, Dialogs Slide # 29

      // Called when user hits the enter key
      firstName.addActionListener( new ActionListener() {
            public void actionPerformed( ActionEvent event ) {
               System.out.println( "Action Event " + 
                  event.getActionCommand() );
            }
         });
      // Called when button is pressed.
      done.addActionListener( new ActionListener() {
            public void actionPerformed( ActionEvent event ) {
               System.out.println("Your name is: " + 
                     firstName.getText() +" " + lastName.getText() );
            }
         });
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  TextFieldExample(300, 150);
   }
}

Q-dec3 1min Doc 31, Fonts, Components, Dialogs Slide # 30

import java.awt.*;
import java.awt.event.*;
class  TextValidationExample  extends Frame  {
   TextField height;
   TextField width;
      
   public TextValidationExample( int  widthInPixels, 
                                       int heightInPixels ) {
      setTitle( "Text Field Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new GridLayout(2, 1) );
      
      int numberOfColumns = 5;
      height = new TextField(  numberOfColumns );
      Panel heightPanel = new Panel( new FlowLayout() );
      heightPanel.add( new Label( "Window height", Label.RIGHT ));
      heightPanel.add( height );
      
      width = new TextField(  numberOfColumns );
      Panel widthPanel = new Panel( new FlowLayout() );
      widthPanel.add( new Label( "Window width", Label.RIGHT ) );
      widthPanel.add( width );
      
      add( heightPanel );
      add( widthPanel );
Q-dec3 5mins Doc 31, Fonts, Components, Dialogs Slide # 31

      IntegerValidator validator = new IntegerValidator();
      height.addActionListener( validator );
      height.addFocusListener( validator );
      width.addActionListener( validator );
      width.addFocusListener( validator );
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  TextValidationExample(300, 150);
   }
}
class IntegerValidator extends FocusAdapter 
                           implements ActionListener {
                           
   public void actionPerformed( ActionEvent event ) {
      validate( (TextField) event.getSource() );
   }
   public void focusLost( ActionEvent event ) {
      validate( (TextField) event.getSource() );
   }
   
   private void validate( TextField field ) {
      try {
         Integer.parseInt( field.getText() );
      }
      catch (NumberFormatException error ) {
         Toolkit.getDefaultToolkit().beep();
         field.requestFocus();
         field.selectAll();
      }
   }
}
Doc 31, Fonts, Components, Dialogs Slide # 32

Q-dec3 3mins Doc 31, Fonts, Components, Dialogs Slide # 33

ScrollPane

import java.awt.*;
import java.awt.event.*;
class  ScrollPaneExample  extends Frame  {
   ScrollPane aScrollPane = new ScrollPane();
      
   public ScrollPaneExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Scroll Example" );
      setSize( widthInPixels, heightInPixels );
      
      aScrollPane.add( new DrawXCanvas() );
      add( BorderLayout.CENTER, aScrollPane );
      
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  ScrollPaneExample(300, 150);
   }
}
Q-dec3 48secs Doc 31, Fonts, Components, Dialogs Slide # 34

class DrawXCanvas extends Canvas{
   int width = 200;
   int height = 400;
   
   public void paint( Graphics drawOnMe ){
      drawOnMe.drawLine( 0, 0, width, height );
      drawOnMe.drawLine( width, 0, 0, height );
   }
      
   public Dimension preferredSize() {
      return new Dimension( width, height );
   }
   public Dimension minimumSize() {
      return preferredSize();
   }
}

Doc 31, Fonts, Components, Dialogs Slide # 35

Dialogs

• Thread execution
• Input to other windows

Constructs an initially invisible Dialog with an empty title.

Constructs an initially invisible Dialog with an empty title. If modal is true, then block input from the parent frame when dialog is shown.

Constructs an initially invisible Dialog with a title.

Constructs an initially invisible Dialog with a title. If modal is true, then block input from the parent frame when dialog is shown.

Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 36

import java.awt.*;
import java.awt.event.*;
class  LoginDialog  extends Dialog  {
   TextField password;
   Button done = new Button( "OK" );
      
   public LoginDialog( Frame owner ) {
      super( owner, "Log in", true );
      setSize( 200, 100 );
      setLocation( 50, 50 );
      setLayout( new GridLayout(2, 1) );
      
      int numberOfColumns = 10;
      password = new TextField( numberOfColumns );
      password.setEchoChar( '*' );
      Panel first = new Panel( new FlowLayout() );
      first.add( new Label( "Password", Label.RIGHT ));
      first.add( password );
      
      Panel buttons = 
         new Panel( new FlowLayout( FlowLayout.CENTER));
      buttons.add( done );
      
      add( first );      add( buttons );
      done.addActionListener( new ActionListener() {
            public void actionPerformed( ActionEvent event ) {
               setVisible(false);
            }
         });
   }
   public String getPassword() {   return password.getText(); }
}
Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 37

class  DialogExample  extends Frame  {
   public DialogExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Validation Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
            
      Button login = new Button( "Log in" );
      login.addActionListener( new Login() );
      add( login );
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  DialogExample(100, 50);
   }
   
   class Login implements ActionListener {
      public  void actionPerformed( ActionEvent event ) {
         LoginDialog passwordDialog = 
               new LoginDialog( DialogExample.this );
         passwordDialog.show(  );
         System.out.println( "Password is: " + 
            passwordDialog.getPassword() );
      }
   }
}
Doc 31, Fonts, Components, Dialogs Slide # 38

S-dec2 3mins, Q-dec3 2mins Doc 31, Fonts, Components, Dialogs Slide # 39

FileDialog

import java.awt.*;
import java.awt.event.*;
class JavaFiles implements java.io.FilenameFilter {
   public boolean accept( java.io.File directory, String name ) {
      return name.endsWith( ".java" );
   }
}
class  FileDialogExample  extends Frame  {
   public FileDialogExample( int widthInPixels, int heightInPixels ) {
      setTitle( "File Dialog Example" );
      setSize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
            
      Button file = new Button( "Select File" );
      file.addActionListener( new FileExample() );
      add( file );
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  FileDialogExample(100, 50);
   }
   
S-dec2 4mins, Q-dec3 1min Doc 31, Fonts, Components, Dialogs Slide # 40

   class FileExample implements ActionListener {
      public  void actionPerformed( ActionEvent event ) {
         FileDialog files = 
            new FileDialog( FileDialogExample.this, "Select a File" );
         files.setFilenameFilter( new JavaFiles() );
         files.show(  );
         System.out.println( "Directory: " + files.getDirectory() );
         System.out.println( "File: " + files.getFile() );
      }
   }
}

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