painter.java

MVC设计模式早在面向对象语言Smalltalk-80中就被提出并在此后得到业界的广泛接受。它包括三类对象：（1）模型（Model）对象：是应用程序的主体部分。（2）视图（View）对象：是应用程序中

/********************************************************************************************/
/*                                                                                          */
/*                              Painter.java                                                */
/*                                                                                          */
/*                    画布显示模块，实现了Observer接口，直接监听与格点有关的事件            */
/*                                                                                          */
/*                      Programed by Luo Pengkui on 2004-9                                  */
/*                                                                                          */
/********************************************************************************************/

import javax.swing.*;
import java.awt.*;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Observable;
import java.util.Observer;
import java.awt.geom.Ellipse2D;

//------------------------------------ BEGIN ------------------------------------------------

public class Painter implements Observer                        // 实现Observer接口
{
    SnakeControl m_control = null;
    SnakeModel m_snake = null;
    MatrixModel m_matrix;
    FoodModel[] m_foods;
    Color m_mapColor;

    Canvas m_paintCanvas;
    JLabel m_labelScore;
    JLabel m_labelEatenNum;

    public static int canvasWidth = 200;
    public static int canvasHeight = 300;

    public static final int nodeWidth = 10;
    public static final int nodeHeight = 10;

    public static final int EMPTY = 0;
    public static final int FRUIT = 1;
    public static final int SNAKE = 2;
    public static final int WALL  = 3;


    public Painter(SnakeModel snake, SnakeControl control,
        FoodModel[] foods, MatrixModel matrix, Color mapColor,
        int canvasCol, int canvasRow, Container cp )
    {
        m_snake = snake;
        m_control = control;
        m_foods = foods;
        m_matrix = matrix;
        m_mapColor = mapColor;
        canvasWidth = canvasCol*nodeWidth;
        canvasHeight = canvasRow*nodeHeight;

        // 创建顶部的分数显示
        m_labelScore = new JLabel("    Score:");
        cp.add(m_labelScore, BorderLayout.NORTH);

        // 创建中间的游戏显示区域
        m_paintCanvas = new Canvas();
        m_paintCanvas.setSize(canvasWidth + 1, canvasHeight + 1);
        m_paintCanvas.addKeyListener(m_control);
        cp.add(m_paintCanvas, BorderLayout.CENTER);
    }

    void repaint()
    {
        Graphics g = m_paintCanvas.getGraphics();
        Graphics2D g2d = ( Graphics2D )g;

        // 填充背景
        g.setColor(m_mapColor);
        g.fillRect(nodeWidth, nodeHeight, canvasWidth-2*nodeWidth, canvasHeight-2*nodeHeight);

        // 画果实
        g.setColor(Color.GREEN);
        for ( int j=0; j<m_foods.length; j++ )
        {
            Point position = m_foods[j].mb_getPosition();
            if ( m_matrix.mb_getGridState( position.x, position.y ) == FRUIT )
            {
                g2d.fill( new Ellipse2D.Double(
                    (position.x)*nodeWidth-1, (position.y)*nodeHeight-1 ,
                    nodeWidth, nodeHeight ) );
            }
        }

        // 过贪吃蛇
        g.setColor(Color.RED);
        LinkedList na = m_snake.mb_getNodeArray();
        Iterator it = na.iterator();
        while (it.hasNext())
        {
            Point n = (Point) it.next();
            drawNode(g, n);
            g.setColor(Color.BLACK);
        }

        updateScore();

    }

    private void drawNode(Graphics g, Point n)                  // 画一个格点
    {
        g.fillRect(n.x * nodeWidth, n.y * nodeHeight, nodeWidth - 1, nodeHeight - 1);
    }

    public void updateScore()                                   // 更新分数
    {
        String s = "Score: " + m_snake.mb_getScoreModel().mb_getScore();
        m_labelScore.setText(s);
    }

    public void update(Observable o, Object arg)                // 被setChanged()和notifyObservers()激活
    {
        repaint();
    }
}

//------------------------------------- END -------------------------------------------------