SDSU CS535 Object-Oriented Programming & Design
Fall Semester, 1996
Doc 25 AWT Lists, Menus, Text

[To Lecture Notes Index]
San Diego State University -- This page last updated Nov 19, 1996
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Contents of Doc 25 AWT Lists, Menus, Text

  1. References
    1. Checkbox
    2. Checkbox Groups - Radio buttons
    3. Choice Boxes - Drop-down Lists
    4. List Box
    5. Text Area
    6. TextField
    7. Label
    8. Menu
Doc 25 AWT Lists, Menus, Text Slide # 1

References


Core Java, Chapter 7
Doc 25 AWT Lists, Menus, Text Slide # 2Listen Here!

Checkbox 

import java.awt.*;

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" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( left );
      add( right );
      show();
   }

   public boolean action( Event processNow, Object checkBoxState ) {
      if ( processNow.target.equals( left ) )
         reportChange( left );
      else if ( processNow.target.equals( right ) )
         reportChange( right );
      else return super.action( processNow, checkBoxState );
      return true;
   }
   
   private void reportChange( Checkbox selectedBox ) {
      System.out.print( selectedBox.getLabel() + " box changed " );
      System.out.println( "value is " + selectedBox.getState() );
   }
      
   public  static  void  main( String  args[] ) {
      new  CheckboxExample(200, 50);
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 3
Output
Checkbox Constructors

Checkbox()
Constructs a Checkbox with no label, no Checkbox group, and initialized to a false state.
Checkbox(String)
Constructs a Checkbox with the specified label, no Checkbox group, and initialized to a false state.
Checkbox(String, CheckboxGroup, boolean)
Constructs a Checkbox with the specified label, specified Checkbox group, and specified boolean state.
Checkbox Methods 
getCheckboxGroup()
getLabel()
getState()
setCheckboxGroup(CheckboxGroup)
setLabel(String)
setState(boolean)



Doc 25 AWT Lists, Menus, Text Slide # 4
Changing Checkbox label 
import java.awt.*;

class  CheckboxExample  extends Frame  {
   private Checkbox toggle = new Checkbox( "Off");
      
   public CheckboxExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Checkbox Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( toggle );
      show();
   }

   public boolean action( Event processNow, Object checkBoxState ) {
      if ( processNow.target.equals( toggle ) )
         changeLabel( toggle );
      else return super.action( processNow, checkBoxState );
      return true;
   }
   
   private void changeLabel( Checkbox selectedBox ) {
      if ( selectedBox.getState() == true )
         selectedBox.setLabel( "On" );
      else if  ( selectedBox.getState() == false )
         selectedBox.setLabel( "Off" );
   }
      
   public  static  void  main( String  args[] ){
      new  CheckboxExample(200, 50);
   }
}
Output 
Doc 25 AWT Lists, Menus, Text Slide # 5

Checkbox Groups - Radio buttons 

import java.awt.*;

class  RadioButton  extends Frame  {

   private CheckboxGroup directions = new CheckboxGroup();
   private Checkbox left = new Checkbox( "Left", directions, false);
   private Checkbox right = new Checkbox( "Right", directions, true);
      
   public RadioButton( int  widthInPixels, int heightInPixels ) {
      setTitle( "Radio Button Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( left );
      add( right );
      show();
   }

   public boolean action( Event processNow, Object checkBoxState) {
      if ( processNow.target.equals( left ) )
         reportChange( left );
      else if ( processNow.target.equals( right ) )
         reportChange( right );
      else return super.action( processNow, checkBoxState);
      return true;
   }
   
   private void reportChange( Checkbox selectedBox ) {
      System.out.print( selectedBox.getLabel() + " box changed " );
      System.out.println( "value is " + selectedBox.getState() );
   }
      
   public  static  void  main( String  args[] ) {
      new  RadioButton(200, 50);
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 6
Output

CheckboxGroup Methods
getCurrent() setCurrent(Checkbox)

Doc 25 AWT Lists, Menus, Text Slide # 7

Choice Boxes - Drop-down Lists 

import java.awt.*;

class  ChoiceBoxes  extends Frame  {

   Choice directions = new Choice();
      
   public ChoiceBoxes( int  widthInPixels, int heightInPixels ) {
      setTitle( "ChoiceBox Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      directions.addItem( "Left" );
      directions.addItem( "Right" );
      directions.addItem( "Up" );
      directions.addItem( "Down" );
      add( directions );
      show();
   }

   public boolean action( Event processNow, Object textSelected ) {
      if ( processNow.target == directions  )
         System.out.println( "You selected " + 
                              ( String ) textSelected );
      else return super.action( processNow, textSelected );
      return true;
   }
      
   public  static  void  main( String  args[] ) {
      new  ChoiceBoxes(200, 200);
   }
}


Doc 25 AWT Lists, Menus, Text Slide # 8
Output
Choice Methods
addItem(String)getItem(int)paramString()
addNotify()getSelectedIndex()select(int)
countItems()getSelectedItem()select(String)

Doc 25 AWT Lists, Menus, Text Slide # 9

List Box 

import java.awt.*;

class  ListExample  extends Frame  {

   List directions ;
      
   public ListExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "List Box Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      boolean areMultipleSelectionsAllowed = false;
      int numberDisplayed = 4;
      directions = new List( numberDisplayed, 
                        areMultipleSelectionsAllowed );

      directions.addItem( "Left" );
      directions.addItem( "Right" );
      directions.addItem( "Up" );
      directions.addItem( "Down" );
      add( directions );
      show();
   }

   public boolean action( Event processNow, Object textSelected ) {
      if ( processNow.target.equals( directions ) )
         System.out.println( "You selected " + 
                        ( String ) textSelected );

      else return super.action( processNow, textSelected );
      return true;
   }

   public  static  void  main( String  args[] ) {
      new  ListExample(200, 100);
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 10
Output 

Doc 25 AWT Lists, Menus, Text Slide # 11
List Constructors

List()
Creates a new scrolling list initialized with no visible Lines or multiple selections.
List(int, boolean)
Creates a new scrolling list initialized with the specified number of visible lines and a boolean stating whether multiple selections are allowed or not.
List Methods
addItem(String)getSelectedItems()
addItem(String,int)getVisibleIndex()
addNotify()isSelected(int)
allowsMultipleSelections()makeVisible(int)
clear()minimumSize()
countItems()minimumSize(int)
delItem(int)paramString()
delItems(int,int)preferredSize()
deselect(int)preferredSize(int)
getItem(int)removeNotify()
getRows()replaceItem(String,int)
getSelectedIndex()select(int)
getSelectedIndexes()setMultipleSelections(boolean)
getSelectedItem()

Doc 25 AWT Lists, Menus, Text Slide # 12

Text Area 

import java.awt.*;

class  TextAreas  extends Frame  {

   TextArea userInput;
   Button done = new Button( "Done Typing" );
      
   public TextAreas( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Area Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      int numberOfLines = 3;
      int numberOfColumns = 30;
      userInput = new TextArea( numberOfLines, numberOfColumns );
      add( userInput );
      add( done );
      show();
   }

   public boolean action( Event processNow, Object buttonLabel ) {
      if ( processNow.target == done )
         checkUserInput();
      else return super.action( processNow, buttonLabel );
      return true;
   }
   
   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);
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 13
Output 



Doc 25 AWT Lists, Menus, Text Slide # 14
TextArea Constructors

TextArea()
Constructs a new TextArea.
TextArea(int, int)
Constructs a new TextArea with the specified number of rows and columns.
TextArea(String)
Constructs a new TextArea with the specified text displayed.
TextArea(String, int, int)
Constructs a new TextArea with the specified text and number of rows and columns.

TextArea Methods
addNotify()minimumSize(int,int)
appendText(String)paramString()
getColumns()preferredSize()
getRows()preferredSize(int,int)
insertText(String,int)replaceText(String,int,int)
minimumSize()

Doc 25 AWT Lists, Menus, Text Slide # 15
How can I tell when the user is done Typing? 
class TextEvents extends TextArea {
   public TextEvents( int numberOfLines, int numberOfColumns ) {
      super( numberOfLines, numberOfColumns );
   }
   
   public boolean handleEvent( Event userAction ) { 
      if ( userAction.id == Event.ACTION_EVENT ) 
         System.out.println( "ACTION_EVENT" );
      else if ( userAction.id == Event.DOWN ) 
         System.out.println( "DOWN" );
      else if ( userAction.id == Event.GOT_FOCUS ) 
         System.out.println( "GOT_FOCUS" );
      else if ( userAction.id == Event.KEY_ACTION ) 
         System.out.println( "KEY_ACTION" );
      else if ( userAction.id == Event.KEY_ACTION_RELEASE ) 
         System.out.println( "KEY_ACTION_RELEASE" );
      else if ( userAction.id == Event.KEY_PRESS ) 
         System.out.println( "KEY_PRESS" );
      else if ( userAction.id == Event.KEY_RELEASE ) 
         System.out.println( "KEY_RELEASE" );
      else if ( userAction.id == Event.LOST_FOCUS ) 
         System.out.println( "LOST_FOCUS" );
      else if ( userAction.id == Event.MOUSE_DOWN ) 
         System.out.println( "MOUSE_DOWN" );
      else if ( userAction.id == Event.MOUSE_DRAG ) 
         System.out.println( "MOUSE_DRAG" );
      else if ( userAction.id == Event.MOUSE_ENTER ) 
         System.out.println( "MOUSE_ENTER" );
      else if ( userAction.id == Event.MOUSE_EXIT ) 
         System.out.println( "MOUSE_EXIT" );
      else if ( userAction.id == Event.MOUSE_MOVE ) 
         System.out.println( "MOUSE_MOVE" );
      else if ( userAction.id == Event.MOUSE_UP ) 
         System.out.println( "MOUSE_UP" );
      return super.handleEvent( userAction );
   }


Doc 25 AWT Lists, Menus, Text Slide # 16
Result of "Is User Done Typing?" 
class  TextAreas  extends Frame  {

   public TextAreas( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Area Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      add( new TextEvents( 3, 30 ) );
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  TextAreas(300, 150);
   }
}




Doc 25 AWT Lists, Menus, Text Slide # 17

TextField 

import java.awt.*;

class  TextExample  extends Frame  {

   TextField userInput;
      
   public TextExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Field Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      String initialText = "Hi Dad";
      int numberOfColumns = 30;
      userInput = new TextField( initialText, numberOfColumns );
      add( userInput );
      add( new Button( "Done Typing" ) );
      show();
   }

   public boolean action( Event processNow, Object buttonPressed ) {
      if ( buttonPressed.equals( "Done Typing" ) )
         checkUserInput();
      else return super.action( processNow, buttonPressed );
      return true;
   }
   
   private void checkUserInput() {
      System.out.println( "You typed: " +  userInput.getText() );
      System.out.println( "Selected text>" +  
                        userInput.getSelectedText() +"<" );
      userInput.setText( "Hi Mom");
      userInput.setEchoCharacter( 'X' );
   }   
   public  static  void  main( String  args[] ) {
      new  TextExample( 300, 200 );
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 18
TextField Constructors

TextField()
Constructs a new TextField.
TextField(int)
Constructs a new TextField initialized with the specified columns.
TextField(String)
Constructs a new TextField initialized with the specified text.
TextField(String, int)
Constructs a new TextField initialized with the specified text and columns.
TextField Methods
addNotify()minimumSize(int)
echoCharIsSet()paramString()
getColumns()preferredSize()
getEchoChar()preferredSize(int)
minimumSize()setEchoCharacter(char)

Doc 25 AWT Lists, Menus, Text Slide # 19
Is the User Done Typing? 
class TextEvents extends TextField  {
   public TextEvents( String text, int numberOfColumns ) {
      super( text, numberOfColumns );
   }
   
   public boolean handleEvent( Event userAction ) { 
      if ( userAction.id == Event.ACTION_EVENT ) 
         System.out.println( "ACTION_EVENT" );
      else if ( userAction.id == Event.DOWN ) 
         System.out.println( "DOWN" );
      else if ( userAction.id == Event.GOT_FOCUS ) 
         System.out.println( "GOT_FOCUS" );
      else if ( userAction.id == Event.KEY_ACTION ) 
         System.out.println( "KEY_ACTION" );
      else if ( userAction.id == Event.KEY_ACTION_RELEASE ) 
         System.out.println( "KEY_ACTION_RELEASE" );
      else if ( userAction.id == Event.KEY_PRESS ) 
         System.out.println( "KEY_PRESS" );
      else if ( userAction.id == Event.KEY_RELEASE ) 
         System.out.println( "KEY_RELEASE" );
      else if ( userAction.id == Event.LOST_FOCUS ) 
         System.out.println( "LOST_FOCUS" );
      else if ( userAction.id == Event.MOUSE_DOWN ) 
         System.out.println( "MOUSE_DOWN" );
      else if ( userAction.id == Event.MOUSE_DRAG ) 
         System.out.println( "MOUSE_DRAG" );
      else if ( userAction.id == Event.MOUSE_ENTER ) 
         System.out.println( "MOUSE_ENTER" );
      else if ( userAction.id == Event.MOUSE_EXIT ) 
         System.out.println( "MOUSE_EXIT" );
      else if ( userAction.id == Event.MOUSE_MOVE ) 
         System.out.println( "MOUSE_MOVE" );
      else if ( userAction.id == Event.MOUSE_UP ) 
         System.out.println( "MOUSE_UP" );
      return super.handleEvent( userAction );
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 20
Result of "User Done Typing" 
class  TextAreas  extends Frame  {

   public TextAreas( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Area Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      add( new TextEvents( "a", 30 ) );
      add( new TextEvents( "b", 30 ) );
      show();
   }
   
   public  static  void  main( String  args[] ) {
      new  TextAreas(300, 150);
   }
}


Doc 25 AWT Lists, Menus, Text Slide # 21

Label 

import java.awt.*;

class  LabelExample  extends Frame  {
      
   public LabelExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Label Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      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 ) );

      show();
   }   
   
   public  static  void  main( String  args[] ) {
      new  LabelExample(150, 100);
   }
}


Doc 25 AWT Lists, Menus, Text Slide # 22
Label With Text 
import java.awt.*;

class  TextExample  extends Frame  {

   TextField userInput;
      
   public TextExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Text Field Example" );
      resize( widthInPixels, heightInPixels );
      setLayout( new FlowLayout() );
      
      add( new Label( "Type Here", Label.RIGHT ) );

      int numberOfColumns = 20;
      userInput = new TextField( "", numberOfColumns );
      add( userInput );
      add( new Button( "Done Typing" ) );
      show();
   }

   public boolean action( Event processNow, Object buttonPressed ) {
      if ( buttonPressed.equals( "Done Typing" ) )
         checkUserInput();
      else return super.action( processNow, buttonPressed );
      return true;
   }
   
   private void checkUserInput() {
      System.out.println( "You typed: " +  userInput.getText() );
   }

   public  static  void  main( String  args[] ) {
      new  TextExample( 300, 200 );
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 23
Label Constructors

Label()
Constructs an empty label.
Label(String)
Constructs a new label with the specified String of text.
Label(String, int)
Constructs a new label with the specified String of text and the specified alignment.
Label Constants
CENTERLEFTRIGHT
Label Methods
addNotify()paramString()
getAlignment()setAlignment(int)
getText()setText(String)

Doc 25 AWT Lists, Menus, Text Slide # 24Listen Here!

Menu 

import java.awt.*;

class  MenuExample  extends Frame  {
      
   public MenuExample( int  widthInPixels, int heightInPixels ) {
      setTitle( "Menu Example" );
      
      MenuBar allMenus = new MenuBar();
      
      Menu gradeMenu = new Menu( "Grade" );
      gradeMenu.add( new MenuItem( "A" ) );
      gradeMenu.add( new MenuItem( "B" ) );
      gradeMenu.addSeparator();
      gradeMenu.add( new MenuItem( "C" ) );
      gradeMenu.addSeparator();
      
      Menu failingGradeMenu = new  Menu( "Bad News" );
      failingGradeMenu.add( new MenuItem( "D" ) );
      failingGradeMenu.add( new CheckboxMenuItem( "F" ) );
      
      gradeMenu.add( failingGradeMenu );
      allMenus.add( gradeMenu );
      setMenuBar( allMenus );
      show();
   }

   public boolean action( Event processNow, Object menuItem ) {
      if ( processNow.target instanceof MenuItem )
         if ( menuItem.equals( "F" ) )
            System.out.println( "Trouble" );
      else return super.action( processNow, menuItem );
      return true;
   }
   
   public  static  void  main( String  args[] ) {
      new  MenuExample( 200, 100 );
   }
}

Doc 25 AWT Lists, Menus, Text Slide # 25Listen Here!
Menu Classes
MenuComponent
getFont()paramString()setFont(Font)
getParent()postEvent(Event)toString()
getPeer()removeNotify()
MenuBar
add(Menu)getHelpMenu()remove(MenuComponent)
addNotify()getMenu(int)removeNotify()
countMenus()remove(int)setHelpMenu(Menu)
MenuItem
addNotify()getLabel()
disable()isEnabled()
enable()paramString()
enable(boolean)setLabel(String)

Doc 25 AWT Lists, Menus, Text Slide # 26
Menu
add(MenuItem)getItem(int)
add(String)isTearOff()
addNotify()remove(int)
addSeparator()remove(MenuComponent)
countItems()removeNotify()
CheckboxMenuItem
addNotify()paramString()
getState()setState(boolean)



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