//  MovingBallMIDlet.java  Copyright (c) Kari Laitinen

//  http://www.naturalprogramming.com/

//  2002-??-??  File created.
//  2007-09-17  Last modification.

/*  This program shows how to use a List object.

    The program displays a ball that can be moved with the
    arrow keys of the mobile phone.

*/


import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;


class MovingBallCanvas extends Canvas
                       implements  CommandListener
{
   MIDlet  master_midlet ;
   Display midlet_display ;

   int ball_position_x, ball_position_y ;

   //  The color is specified with a hexadecimal value 0x00RRGGBB
   //  so that each color component (red, green, and blue) can
   //  have value 0 ... 0xFF. 

   int  current_color   =    0x00FF0000 ;  //  red is the initial color

   //  The following two initialized arrays must be organized so that
   //  the RGB value of a color has the same index as the name
   //  of the color in question.

   int[] rgb_color_specifications  =  {  0x00FF0000,  0x0000FF00,  0x000000FF,
                                         0x007F0000,  0x00007F00,  0x0000007F,
                                         0x0000FFFF,  0x00FF00FF,  0x00FFFF00,
                                         0x00000000,  0x007F7F7F } ;

   String[] selectable_colors      =  { "Red",       "Green",      "Blue",
                                        "Dark red",  "Dark green", "Dark blue",
                                        "Cyan",      "Magenta",    "Yellow",
                                        "Black",     "Grey" } ;

   List  color_selection_list  =  new  List( "Select Ball Color",
                                             List.IMPLICIT,
                                             selectable_colors, null ) ;

   Command  exit_command  =  new Command( "Exit", Command.EXIT, 1 ) ;

   Command  change_color_command  =  new  Command( "Change color",
                                                   Command.SCREEN, 1 ) ;

   public MovingBallCanvas( MIDlet   given_master_midlet,
                            Display  given_display )
   {
      master_midlet   =  given_master_midlet ;
      midlet_display  =  given_display ;

      ball_position_x  =  getWidth()  / 2  -  20 ;
      ball_position_y  =  getHeight() / 2  -  20 ;


      addCommand( change_color_command ) ;
      addCommand( exit_command ) ;

      setCommandListener( this ) ;
      color_selection_list.setCommandListener( this ) ;
   }   

   public void commandAction( Command     given_command,
                              Displayable display_content )
   {
      if ( given_command  ==  change_color_command )
      {
         midlet_display.setCurrent( color_selection_list ) ;
      }
      else if ( given_command  ==  List.SELECT_COMMAND )
      {
         int index_of_selected_color  =  
                     color_selection_list.getSelectedIndex() ;

         //  The following assignment statement selects the right color
         //  when the array pointed by rgb_color_specifications is initialized
         //  so that it corresponds to the array containing the selectable
         //  colors.

         current_color = rgb_color_specifications[ index_of_selected_color ] ;

         midlet_display.setCurrent( this ) ;
      }
      else if ( given_command  ==  exit_command )
      {
         //  With the following method call this midlet informs the 
         //  runtime system that this method is ready for destruction.
         //  The runtime system does not call the destroyApp() method
         //  before the destruction operation.

         master_midlet.notifyDestroyed() ;
      }
   }


   public void keyPressed( int key_code )
   {
      int game_action_code = getGameAction( key_code ) ;

      switch ( game_action_code )
      {
      case UP:
          ball_position_y  -=  3 ;
          break;

      case DOWN:
          ball_position_y  +=  3 ;
          break;

      case RIGHT:
          ball_position_x  +=  3 ;
          break;

      case LEFT:
          ball_position_x  -=  3 ;
          break;
      }

      repaint() ;
   }


   protected void paint( Graphics graphics )
   {
      graphics.setColor( 255, 255, 255 ) ;  //  white
      graphics.fillRect( 0, 0, getWidth(), getHeight() ) ;


      graphics.setColor( current_color ) ;

      graphics.drawRect( 0, 0, getWidth() - 1, getHeight() - 1 ) ;

      graphics.fillArc( ball_position_x, ball_position_y,
                        40, 40, 0, 360 ) ;

      graphics.drawString(  "(" + ball_position_x
                          + ", "  +  ball_position_y  +  ")",
                           2, 0,
                           Graphics.TOP | Graphics.LEFT ) ;
   }
}


public class MovingBallMIDlet extends MIDlet
{
   Display           midlet_display      =  Display.getDisplay( this ) ;
   MovingBallCanvas  moving_ball_canvas  = 
                          new MovingBallCanvas( this, midlet_display ) ;

   public MovingBallMIDlet()
   {
   }

   protected void startApp() throws MIDletStateChangeException
   {
      midlet_display.setCurrent( moving_ball_canvas ) ;
   }

   protected void pauseApp()
   {
   }

   protected void destroyApp( boolean unconditional_destruction_required )
   {
   }
}