I'm practicing MVC style programming. I have a Mastermind game in a single file, working fine (maybe apart of the fact that "Check" button is invisible at start).
http://paste.pocoo.org/show/226726/
But when I've rewritten it to model, view, controller files - and when I click on empty Pin (that should be updated, and repainted with new color) - noting happens. Can anybody see any problems here ? I've tried placing repaint() in different places, but it simply does not work at all :/
Main :
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);
}
}
Model :
import java.util.Random;
public class Model{
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;
Random generator = new Random();
int repaintPin;
boolean pinsRepaint=false;
int pinsToRepaint;
boolean isUpdate = true, isPlaying = true, isRowFull = false;
static final int HIT_X[] = {270,290,310,290,310}, HIT_Y[] = {506,496,496,516,516};
public Model(){
for ( int i=0; i < SCORE; i++ ){
for ( int j = 0; j < LINE; j++ ){
pins[i][j] = new Pin(20,0);
pins[i][j].setPosition(j*50+30,510-i*50);
pins[i+SCORE][j] = new Pin(8,0);
pins[i+SCORE][j].setPosition(HIT_X[j],HIT_Y[j]-i*50);
}
}
for ( int i=0; i < LINE; i++ ){
pins[OPTIONS][i] = new Pin( 20, i+2 );
pins[OPTIONS][i].setPosition( 370,i * 50 + 56);
}
}
void fillHole(int color) {
pins[turn-1][curPin].setColor(color+1);
pinsRepaint = true;
pinsToRepaint = turn;
curPin = (curPin+1) % LINE;
if (curPin == 0){
isRowFull = true;
}
pinsRepaint = false;
pinsToRepaint = 0;
}
void check() {
int junkPins[] = new int[LINE], junkCode[] = new int[LINE];
int pinCount = 0, pico = 0;
for ( int i = 0; i < LINE; i++ ) {
junkPins[i] = pins[turn-1][i].getColor();
junkCode[i] = combination[i];
}
for ( int i = 0; i < LINE; i++ ){
if (junkPins[i]==junkCode[i]) {
pins[turn+SCORE][pinCount].setColor(1);
pinCount++;
pico++;
junkPins[i] = 98;
junkCode[i] = 99;
}
}
for ( int i = 0; i < LINE; i++ ){
for ( int j = 0; j < LINE; j++ )
if (junkPins[i]==junkCode[j]) {
pins[turn+SCORE][pinCount].setColor(2);
pinCount++;
junkPins[i] = 98;
junkCode[j] = 99;
j = LINE;
}
}
pinsRepaint = true;
pinsToRepaint = turn + SCORE;
pinsRepaint = false;
pinsToRepaint=0;
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] = generator.nextInt(6) + 1;
}
}
}
class Pin{
private int color, X, Y, radius;
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 int getX(){
return X;
}
public int getY(){
return Y;
}
public int getRadius(){
return radius;
}
public void setRadius(int r){
radius = r;
}
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;
}
}
View:
import java.awt.*;
import javax.swing.*;
public class View extends Frame{
Model model;
JButton checkAnswer;
private JPanel button;
private static final Color COLORS[] = {Color.black, Color.white, Color.red, Color.yellow, Color.green, Color.blue, new Color(7, 254, 250)};
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.setSize( new Dimension(200, 30));
button.add( checkAnswer );
this.add( button, BorderLayout.SOUTH);
button.setVisible(true);
}
@Override
public void paint( Graphics g ) {
g.setColor( new Color(238, 238, 238));
g.fillRect( 0,0,400,590);
for ( int i=0; i < model.pins.length; i++ ) {
paintPins(model.pins[i][0],g);
paintPins(model.pins[i][1],g);
paintPins(model.pins[i][2],g);
paintPins(model.pins[i][3],g);
paintPins(model.pins[i][4],g);
}
}
@Override
public void update( Graphics g ) {
if ( model.isUpdate ) {
paint(g);
}
else {
model.isUpdate = true;
paintPins(model.pins[model.repaintPin-1][0],g);
paintPins(model.pins[model.repaintPin-1][1],g);
paintPins(model.pins[model.repaintPin-1][2],g);
paintPins(model.pins[model.repaintPin-1][3],g);
paintPins(model.pins[model.repaintPin-1][4],g);
}
}
void repaintPins( int pin ) {
model.repaintPin = pin;
model.isUpdate = false;
repaint();
}
public void paintPins(Pin p, Graphics g ){
int X = p.getX();
int Y = p.getY();
int color = p.getColor();
int radius = p.getRadius();
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 );
}
}
Controller:
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);
view.checkAnswer.addActionListener(this);
model.combination();
}
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);
if(model.pinsRepaint){
view.repaintPins( model.pinsToRepaint );
}
}
}
}
}
public void mouseClicked(MouseEvent e) {}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
}
As you've discovered, the Model–View–Controller pattern is no panacea, but it offers some advantages. Rooted in MVC, the Swing separable model architecture is discussed in A Swing Architecture Overview. Based on this outline, the following example shows an MVC implementation of a much simpler game that illustrates similar principles. Note that the Model
manages a single Piece
, chosen at random. In response to a user's selection, the View
invokes the check()
method, while listening for a response from the Model
via update()
. The View
then updates itself using information obtained from the Model
. Similarly, the Controller
may reset()
the Model
. In particular, there is no drawing in the Model
and no game logic in the View
. This somewhat more complex game was designed to illustrate the same concepts.
Addendum: I've modified the original example to show how MVC allows one to enhance the View
without changing the nature of the Model
.
Addendum: As @akf observes, MVC hinges on the observer pattern. Your Model
needs a way to notify the View
of changes. Several approaches are widely used:
In the example below, Model
extends Observable
for simplicity.
A more common approach uses an EventListenerList
, as shown in the Converter
application and suggested by the large number of EventListener
subinterfaces and implementing classes.
A third option is to use a PropertyChangeListener
, as shown here and here.
Addendum: Some common questions about Swing controllers are addressed here and here.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Observable;
import java.util.Observer;
import java.util.Random;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
* @see https://stackoverflow.com/q/3066590/230513
* 15-Mar-2011 r8 https://stackoverflow.com/questions/5274962
* 26-Mar-2013 r17 per comment
*/
public class MVCGame implements Runnable {
public static void main(String[] args) {
EventQueue.invokeLater(new MVCGame());
}
@Override
public void run() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new MainPanel());
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class MainPanel extends JPanel {
public MainPanel() {
super(new BorderLayout());
Model model = new Model();
View view = new View(model);
Control control = new Control(model, view);
JLabel label = new JLabel("Guess what color!", JLabel.CENTER);
this.add(label, BorderLayout.NORTH);
this.add(view, BorderLayout.CENTER);
this.add(control, BorderLayout.SOUTH);
}
}
/**
* Control panel
*/
class Control extends JPanel {
private Model model;
private View view;
private JButton reset = new JButton("Reset");
public Control(Model model, View view) {
this.model = model;
this.view = view;
this.add(reset);
reset.addActionListener(new ButtonHandler());
}
private class ButtonHandler implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if ("Reset".equals(cmd)) {
model.reset();
}
}
}
}
/**
* View
*/
class View extends JPanel {
private static final String s = "Click a button.";
private Model model;
private ColorIcon icon = new ColorIcon(80, Color.gray);
private JLabel label = new JLabel(s, icon, JLabel.CENTER);
public View(Model model) {
super(new BorderLayout());
this.model = model;
label.setVerticalTextPosition(JLabel.BOTTOM);
label.setHorizontalTextPosition(JLabel.CENTER);
this.add(label, BorderLayout.CENTER);
this.add(genButtonPanel(), BorderLayout.SOUTH);
model.addObserver(new ModelObserver());
}
private JPanel genButtonPanel() {
JPanel panel = new JPanel();
for (Piece p : Piece.values()) {
PieceButton pb = new PieceButton(p);
pb.addActionListener(new ButtonHandler());
panel.add(pb);
}
return panel;
}
private class ModelObserver implements Observer {
@Override
public void update(Observable o, Object arg) {
if (arg == null) {
label.setText(s);
icon.color = Color.gray;
} else {
if ((Boolean) arg) {
label.setText("Win!");
} else {
label.setText("Keep trying.");
}
}
}
}
private class ButtonHandler implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
PieceButton pb = (PieceButton) e.getSource();
icon.color = pb.piece.color;
label.repaint();
model.check(pb.piece);
}
}
private static class PieceButton extends JButton {
Piece piece;
public PieceButton(Piece piece) {
this.piece = piece;
this.setIcon(new ColorIcon(16, piece.color));
}
}
private static class ColorIcon implements Icon {
private int size;
private Color color;
public ColorIcon(int size, Color color) {
this.size = size;
this.color = color;
}
@Override
public void paintIcon(Component c, Graphics g, int x, int y) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(color);
g2d.fillOval(x, y, size, size);
}
@Override
public int getIconWidth() {
return size;
}
@Override
public int getIconHeight() {
return size;
}
}
}
/**
* Model
*/
class Model extends Observable {
private static final Random rnd = new Random();
private static final Piece[] pieces = Piece.values();
private Piece hidden = init();
private Piece init() {
return pieces[rnd.nextInt(pieces.length)];
}
public void reset() {
hidden = init();
setChanged();
notifyObservers();
}
public void check(Piece guess) {
setChanged();
notifyObservers(guess.equals(hidden));
}
}
enum Piece {
Red(Color.red), Green(Color.green), Blue(Color.blue);
public Color color;
private Piece(Color color) {
this.color = color;
}
}