bball4two.java~

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;

// program for two players to play basketball.
public class BBall4Two extends WindowController{

        // Location of the display
        private static final int DISPLAY_X = 150;
        private static final int DISPLAY_Y = 200;
        private static final int DISPLAYSIZE = 16; // in points

        // Location and dimensions of the hoop
        private static final int HOOPTOP = 50;
        private static final int HOOPLEFT = 160;
        private static final int HOOPWIDTH = 80;
        private static final int HOOPHEIGHT = 35;

        // Initial locations and dimensions of the balls
        private static final int BALLX = 110;
        private static final int BALLY = 300;
        private static final int BALLSIZE = 40;
        private static final int BALLSPACING = 160;

        // Distance between balls and score displays
        private static final int SCOREDOWNSET = BALLSIZE + 25;

        // the Text objects which display the scores
        private Text leftDisplay, rightDisplay;

        // the oval that represent the hoop
        private FramedOval hoop;

        // the two balls
        private BBall leftBall, rightBall;

        // the ball currently being dragged
        private BBall ballInPlay;

        // whether any ball is currently in play
    private boolean carryingBall;

        // the scores for each player
        private int leftScore = 0,   rightScore = 0;

        // the last previous known location of the mouse
        private Location lastMouse;

        // initialize the counter and the text message
        public void begin() {

                hoop = new FramedOval( HOOPLEFT, HOOPTOP, HOOPWIDTH, HOOPHEIGHT, canvas);

                leftBall = new BBall( BALLX, BALLY, BALLSIZE, canvas);
                rightBall = new BBall( BALLX + BALLSPACING, BALLY, BALLSIZE, canvas);
                
                leftDisplay = new Text("HOME 0", BALLX + BALLSIZE/2, 
                                                                     BALLY + SCOREDOWNSET,  canvas);
                rightDisplay = new Text("VISITORS 0", BALLX + + BALLSPACING + BALLSIZE/2,
                                                              BALLY + SCOREDOWNSET,   canvas);

                leftDisplay.setFontSize(DISPLAYSIZE);
                leftDisplay.move( - leftDisplay.getWidth()/2,0);
                rightDisplay.setFontSize(DISPLAYSIZE);
                rightDisplay.move( - rightDisplay.getWidth()/2,0);
        }

        // Note where mouse is depressed
        public void onMousePress(Location point) {
                lastMouse = point;
                if ( leftBall.contains( point ) ) 
                {
                        ballInPlay = leftBall;
                        carryingBall = true;
                } 
                else if ( rightBall.contains( point ) ) 
                {
                        ballInPlay = rightBall;
                        carryingBall = true;
                }
        }

        // Move the ball as the mouse is dragged
        public void onMouseDrag(Location point) {
                if ( carryingBall ) 
                {
                        ballInPlay.move( point.getX() - lastMouse.getX(),
                                                 point.getY() - lastMouse.getY() );
                        lastMouse = point;
                }
        }

        // check to see if either player scored
        public void onMouseRelease(Location point) {
                if ( hoop.contains(point) ) 
                {
                        if ( ballInPlay == leftBall ) 
                        {
                                leftScore = leftScore + 2;
                                leftDisplay.setText("HOME " + leftScore );
                        } 
                        else if ( ballInPlay == rightBall ) 
                        {
                                rightScore = rightScore + 2;
                                rightDisplay.setText("VISITORS " + rightScore);
                        }
                }
                
                if ( carryingBall ) 
                {
                        ballInPlay.reset();
                        carryingBall = false;
                }
        }
}