pong.java

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;
import java.awt.*;

// plays a classic version of single player pong
public class Pong extends WindowController{

   private static final int
   // Dimensions of the court
   courtLeft = 50,
   courtTop = 50,
   courtHeight = 300,
   courtWidth = 250,

   // Dimensions of the paddle
   paddleWidth = 50,
   paddleHeight = 20;

   private FilledRect paddle;    // the paddle

   private FramedRect boundary; // the boundary of the playing area.

   public void begin()
   {
      // make the playing area
      boundary = new FramedRect(courtLeft,courtTop,
                                courtWidth, courtHeight,
                                canvas);

      // make the paddle
      paddle =
            new FilledRect(courtLeft + (courtWidth-paddleWidth)/2,
            courtTop + courtHeight - paddleHeight -1,
            paddleWidth, paddleHeight,
            canvas);
   }

   public void onMouseClick(Location point)
   {
      // make a new ball when the player clicks
      new MovingBall(canvas, paddle, boundary);
   }

   public void onMouseMove(Location point)
   {
      if ( point.getX() < courtLeft )
      {
         // place paddle at left edge of the court
         paddle.moveTo( courtLeft,
                        courtTop + courtHeight - paddleHeight -1);
      }
      else if ( point.getX() > courtLeft + courtWidth - paddleWidth)
      {
         // place paddle at right edge of the court
         paddle.moveTo( courtLeft + courtWidth - paddleWidth,
                        courtTop + courtHeight - paddleHeight -1);
      }
      else
      {
         // keep the edge of the paddle lined up with the mouse
         paddle.moveTo( point.getX(),
                        courtTop + courtHeight - paddleHeight -1);
      }
   }

}