//  KeyboardInputDemoApplet.java  (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2006-10-12  File created.
//  2009-11-07  Latest modification.

//  This program shows how a Java program can find out which keys
//  are pressed on the keyboard.

import java.awt.* ;
import java.awt.event.* ;
import javax.swing.* ;

public class KeyboardInputDemoApplet extends JApplet
                                     implements  KeyListener
{
   Font large_font   = new Font( "SansSerif", Font.BOLD, 24 ) ;

   int  code_of_last_pressed_key  =  '?' ;

   public void init()
   {
      addKeyListener( this ) ;
   }

   public void keyPressed( KeyEvent event )
   {
      code_of_last_pressed_key  =  event.getKeyCode() ;  
      repaint() ;

      System.out.print( "\n Method keyPressed() was called.  Key code  =  "
                        +  code_of_last_pressed_key ) ;
   }

   public void keyReleased( KeyEvent event )
   {
      System.out.print( "\n Method keyReleased() was called." ) ;
   }

   public void keyTyped( KeyEvent event )
   {
      System.out.print( "\n Method keyTyped() was called." ) ;
   }

   public void paint( Graphics graphics )
   {
      super.paint( graphics ) ;

      graphics.setFont( large_font ) ;

      //  The following statement prints the code of the last pressed key
      //  as character, as hexadecimal code, and as decimal code.

      graphics.drawString( String.format( "Last pressed key:  %c  %X  %d",
                                          code_of_last_pressed_key,
                                          code_of_last_pressed_key,
                                          code_of_last_pressed_key ), 
                           100, 200 ) ;


      //  The KeyEvent class provides predefined constants (e.g. VK_F1)
      //  which can be used to refer to the individual keys on the keyboard.

      if ( code_of_last_pressed_key  ==  KeyEvent.VK_F1 )
      {
         graphics.drawString( "You pressed the F1 key", 100, 250 ) ;
      }
      else if ( code_of_last_pressed_key  ==  KeyEvent.VK_UP )
      {
         graphics.drawString( "You pressed the Arrow Up key", 100, 250 ) ;
      }
      else if ( code_of_last_pressed_key  ==  KeyEvent.VK_DOWN )
      {
         graphics.drawString( "You pressed the Arrow Down key", 100, 250 ) ;
      }

      //  A window has 'focus' when keyboard input is directed to it.
      //  The following statement ensures that the applet window will
      //  receive keyboard input.

      if ( ! hasFocus() )
      {
         requestFocus() ;
      }
   }
}