将应用程序转换为 MVC 架构

Question

我正在练习编写 MVC 应用程序。我有一个 Mastermind 游戏，我想将其重写为 MVC 应用程序。我已将我的代码分成几个部分，但我没有得到工作游戏，而是得到空框架和“public void Paint( Graphics g )”中的错误。在我看来，错误来自于使用 null 参数调用此方法。但如何克服这个问题呢？ MVC 对于 swing 来说非常简单，但是 awt 及其绘制方法要复杂得多。

工作应用程序代码：
http://paste.pocoo.org/show/224982/

应用程序划分为 MVC ：
主要：

public class Main {

    public static void main(String[] args){

        Model model = new Model();
        View view = new View("Mastermind", 400, 590, model);
        Controller controller = new Controller(model, view);

        view.setVisible(true);
    }
}

控制器：

import java.awt.*;
import java.awt.event.*;

public class Controller implements MouseListener, ActionListener {

    private Model model;
    private View view;

    public Controller(Model m, View v){

        model = m;
        view = v;

        view.addWindowListener( new WindowAdapter(){
            public void windowClosing(WindowEvent e){
            System.exit(0);
        } });

        view.addMouseListener(this);

    }

    public void actionPerformed( ActionEvent e ) {
        if(e.getSource() == view.checkAnswer){
            if(model.isRowFull){
                model.check();
            }
        }
    }

    public void mousePressed(MouseEvent e) {
        Point mouse = new Point();

        mouse = e.getPoint();
        if (model.isPlaying){
            if (mouse.x > 350) {
                int button = 1 + (int)((mouse.y - 32) / 50);
                if ((button >= 1) && (button <= 5)){
                    model.fillHole(button);
                }
            }
        }
    }

    public void mouseClicked(MouseEvent e) {}
    public void mouseReleased(MouseEvent e){}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e)  {}
}

视图：

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

public class View extends Frame implements ActionListener {

    Model model;
    JButton checkAnswer;
    private JPanel button;
    static final int HIT_X[] = {270,290,310,290,310}, HIT_Y[] = {506,496,496,516,516};

    public View(String name, int w, int h, Model m){

        model = m;

        setTitle( name );
        setSize( w,h );
        setResizable( false );
        this.setLayout(new BorderLayout());

        button = new JPanel();
        button.setSize( new Dimension(400, 100));
        button.setVisible(true);
        checkAnswer = new JButton("Check");
        checkAnswer.addActionListener(this);
        checkAnswer.setSize( new Dimension(200, 30));
        button.add( checkAnswer );
        this.add( button, BorderLayout.SOUTH);
        button.setVisible(true);

        for ( int i=0; i < model.SCORE; i++ ){
            for ( int j = 0; j < model.LINE; j++ ){
                model.pins[i][j] = new Pin(20,0);
                model.pins[i][j].setPosition(j*50+30,510-i*50);
                model.pins[i+model.SCORE][j] = new Pin(8,0);
                model.pins[i+model.SCORE][j].setPosition(HIT_X[j],HIT_Y[j]-i*50);
            }
        }
        for ( int i=0; i < model.LINE; i++ ){
            model.pins[model.OPTIONS][i] = new Pin( 20, i+2 );
            model.pins[model.OPTIONS][i].setPosition( 370,i * 50 + 56);
        }
        model.combination();

        model.paint(null);
    }

    public void actionPerformed( ActionEvent e ) {
    }   
}

模型：

import java.awt.*;

public class Model extends Frame{
    static final int
    LINE = 5,
    SCORE = 10, OPTIONS = 20;
    Pin pins[][] = new Pin[21][LINE];
    int combination[] = new int[LINE];
    int curPin = 0;
    int turn = 1;
    int repaintPin;
    boolean isUpdate = true, isPlaying = true, isRowFull = false;

    public Model(){
    }

    void fillHole(int color) {
        pins[turn-1][curPin].setColor(color+1);
        repaintPins( turn );
        curPin = (curPin+1) % LINE;
        if (curPin == 0){
            isRowFull = true;
        }
    }

    public void paint( Graphics g ) {
        g.setColor( new Color(238, 238, 238));
        g.fillRect( 0,0,400,590);

        for ( int i=0; i < pins.length; i++ ) {
            pins[i][0].paint(g);
            pins[i][1].paint(g);
            pins[i][2].paint(g);
            pins[i][3].paint(g);
            pins[i][4].paint(g);
        }
    }

    public void update( Graphics g ) {
        if ( isUpdate ) {
            paint(g);
        }
        else {
            isUpdate = true;
            pins[repaintPin-1][0].paint(g);
            pins[repaintPin-1][1].paint(g);
            pins[repaintPin-1][2].paint(g);
            pins[repaintPin-1][3].paint(g);
            pins[repaintPin-1][4].paint(g);
        }
    }

    void repaintPins( int pin ) {
        repaintPin = pin;
        isUpdate = false;
        repaint();
    }

    void check() {
        int junkPegs[] = new int[LINE], junkCode[] = new int[LINE];
        int pegCount = 0, pico = 0;

        for ( int i = 0; i < LINE; i++ ) {
            junkPegs[i] = pins[turn-1][i].getColor();
            junkCode[i] = combination[i];
        }
        for ( int i = 0; i < LINE; i++ ){
            if (junkPegs[i]==junkCode[i]) {
                pins[turn+SCORE][pegCount].setColor(1);
                pegCount++;
                pico++;
                junkPegs[i] = 98;
                junkCode[i] = 99;
            }
        }
        for ( int i = 0; i < LINE; i++ ){
            for ( int j = 0; j < LINE; j++ )
                if (junkPegs[i]==junkCode[j]) {
                    pins[turn+SCORE][pegCount].setColor(2);
                    pegCount++;
                    junkPegs[i] = 98;
                    junkCode[j] = 99;
                    j = LINE;
            }
        }
        repaintPins( turn+SCORE );

        if ( pico == LINE ){
            isPlaying = false;
        }
        else if ( turn >= 10 ){
                isPlaying = false;
        }
        else{
            curPin = 0;
            isRowFull = false;
            turn++;
        }
    }

    void combination() {
        for ( int i = 0; i < LINE; i++ ){
          combination[i] = 1 + (int)(Math.random()*5);
            System.out.print(i+",");
        }
    }
}

class Pin{
    private int color, X, Y, radius;
    private static final Color COLORS[] = {
        Color.black,
        Color.white,
        Color.red,
        Color.yellow,
        Color.green,
        Color.blue,
        new Color(7, 254, 250)};

    public Pin(){
        X = 0; Y = 0; radius = 0; color = 0;
    }

    public Pin( int r,int c ){
        X = 0; Y = 0; radius = r; color = c;
    }

    public void paint( Graphics g ){
        int x = X-radius;
        int y = Y-radius;

        if (color > 0){
            g.setColor( COLORS[color]);
            g.fillOval( x,y,2*radius,2*radius );
        }
        else{
            g.setColor( new Color(238, 238, 238) );
            g.drawOval( x,y,2*radius-1,2*radius-1 );
        }
        g.setColor( Color.black );
        g.drawOval( x,y,2*radius,2*radius );
    }

    public void setPosition( int x,int y ){
        this.X = x ;
        this.Y = y ;
    }
    public void setColor( int c ){
        color = c;
    }
    public int getColor() {
        return color;
    }
}

有关如何克服此问题的任何线索都很棒。我的代码划分是否不当？

Answer 1

这对我来说看起来不太合适。

模型不应扩展框架。框架是一个视图的想法。模型中不应包含图形、绘画或除当前问题之外的任何内容。

我不会让 View 实现任何 Listener 接口。这是控制器的工作。监听器负责处理所有事件并更新模型以响应从视图事件接收到的更改。

View 应该只是 Swing 或 AWT 类；没有听众。 Paint方法属于View。任何绘制的内容都应该在视图中表达。

模型和视图都不应该互相引用或控制器；控制器拥有对模型和视图的引用。这是知道整个问题的全知者。

模型只知道您正在解决的问题。

视图应该是完全可拆卸的。一个好的测试是能够删除 Swing UI 并编写一个纯文本驱动的 View 来替换它。如果你能做到这一点而不影响其他两个，那么你就已经正确地分层了。