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How to have the program regenerate a "new game" where previous grid letters get swapped with new grid letters

In this program I'm trying to input a functionality to start game, where if I click start game (MainMenu) a new jpanel opens up (MainGame), creating another jpanel that creates jbuttons in a grid. If i go back, and click start game again, a new grid should generate instead of the previous one, effectively starting a "new game". the problem is that if i go back and click on new game again, the program creates 2 grids.
I've tried removing the instance of the grid panel with = null but it doesn't work
Main function:
import javax.swing.*;
import java.awt.*;
import java.awt.CardLayout;
public class Game extends JFrame {
MainMenu mainMenu;
Settings settings;
MainGame mainGame;
CardLayout cl;
JPanel container;
public Game(){
setSize(900,900); //have all as seperate classes
setDefaultCloseOperation(3); //cl call container
container = new JPanel(); //container call menu1 and menu2
cl = new CardLayout();
mainMenu = new MainMenu();
settings = new Settings();
mainGame = new MainGame();
mainMenu.setSettings(settings);
settings.setMainMenu(mainMenu);
settings.setMainGame(mainGame);
mainMenu.setMainGame(mainGame);
mainGame.setMainMenu(mainMenu);
mainGame.setSettings(settings);
container.setLayout(cl); //this stays here i think
//add setter for main game here
container.add(mainMenu,"1");
container.add(settings,"2");
container.add(mainGame,"3");
mainMenu.setContainer(container);
mainMenu.setCl(cl);
settings.setContainer(container);
settings.setCl(cl);
mainGame.setContainer(container);
mainGame.setCl(cl);
cl.show(container, "1");
add(container,BorderLayout.CENTER);
}
public static void main(String[] args) {
Game game = new Game();
game.setVisible(true);
}
}
main game class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class MainGame extends JPanel {
MainMenu mainMenu;
Settings settings;
CardLayout cl;
JPanel container;
String rows;
String columns;
public void setMainMenu(MainMenu mainMenu) {
this.mainMenu = mainMenu;
}
public void setSettings(Settings settings) {
this.settings = settings;
}
public void setCl(CardLayout cl) {
this.cl = cl;
}
public void setContainer(JPanel container) {
this.container = container;
}
public void setRows(String rows) {
this.rows = rows;
}
public void setColumns(String columns) {
this.columns = columns;
}
public MainGame(){
JPanel north = new JPanel();
north.setLayout(new FlowLayout());
ReturnAction returnAl = new ReturnAction();
JButton Return2 = new JButton("Return");
Return2.addActionListener(returnAl);
north.add(Return2);
add(north);
}
class ReturnAction implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
cl.show(container,"1");
}
}
}
Main menu class (this one contains the game generation part):
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
public class MainMenu extends JPanel {
JPanel grid = new JPanel();
MainGame mainGame;
Settings settings;
CardLayout cl;
JPanel container;
String rows;
String columns;
boolean checkexists = false;
int rownumber;
int columnnumber;
public void setMainGame(MainGame mainGame) {
this.mainGame = mainGame;
}
public void setCl(CardLayout cl) {
this.cl = cl;
}
public void setContainer(JPanel container) {
this.container = container;
}
public void setSettings(Settings settings) {
this.settings = settings;
}
public void setRows(String rows) {
this.rows = rows;
}
public void setColumns(String columns) {
this.columns = columns;
}
public MainMenu() {
setLayout(new GridLayout(3, 1));
JButton Newgame = new JButton("New Game");
JButton Cont = new JButton("Continue");
JButton Sett = new JButton("Settings");
add(Newgame);
add(Cont);
SwitchMenu1 switchMenu1 = new SwitchMenu1();
SwitchMenu2 switchMenu2 = new SwitchMenu2();
GenerateGame generateGame = new GenerateGame();
Newgame.addActionListener(switchMenu2);
Newgame.addActionListener(generateGame);
Sett.addActionListener(switchMenu1);
add(Sett);
}
class SwitchMenu1 implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
cl.show(container, "2");
}
}
class SwitchMenu2 implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
cl.show(container, "3");
}
}
class GenerateGame implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (checkexists == true){
grid = null;
grid = new JPanel();
}
try {
rownumber = Integer.parseInt(rows);
} catch (NumberFormatException be) {
rownumber = 10;
}
try {
columnnumber = Integer.parseInt(columns);
} catch (NumberFormatException be) {
columnnumber = 10;
}
Random rand = new Random();
int randomnumber;
String Letters = "AAIIOOUUEEABCDEFGHIJKLMNOPQRSTUVWXYZ";
grid.setLayout(new GridLayout(rownumber, columnnumber));
JButton[][] gridbutton = new JButton[rownumber][columnnumber];
MainbuttonAL mainbuttonAL = new MainbuttonAL();
for (int i = 0; i < rownumber; i++) {
for (int j = 0; j < columnnumber; j++) {
if (checkexists == true){
gridbutton[i][j] = null;
}
randomnumber = rand.nextInt(Letters.length());
gridbutton[i][j] = new JButton("" + Letters.charAt(randomnumber));
gridbutton[i][j].addActionListener(mainbuttonAL);
grid.add(gridbutton[i][j]);
}
}
mainGame.add(grid);
checkexists = true;
}
}
class MainbuttonAL implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
}
}
}
settings class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
public class MainMenu extends JPanel {
JPanel grid = new JPanel();
MainGame mainGame;
Settings settings;
CardLayout cl;
JPanel container;
String rows;
String columns;
boolean checkexists = false;
int rownumber;
int columnnumber;
public void setMainGame(MainGame mainGame) {
this.mainGame = mainGame;
}
public void setCl(CardLayout cl) {
this.cl = cl;
}
public void setContainer(JPanel container) {
this.container = container;
}
public void setSettings(Settings settings) {
this.settings = settings;
}
public void setRows(String rows) {
this.rows = rows;
}
public void setColumns(String columns) {
this.columns = columns;
}
public MainMenu() {
setLayout(new GridLayout(3, 1));
JButton Newgame = new JButton("New Game");
JButton Cont = new JButton("Continue");
JButton Sett = new JButton("Settings");
add(Newgame);
add(Cont);
SwitchMenu1 switchMenu1 = new SwitchMenu1();
SwitchMenu2 switchMenu2 = new SwitchMenu2();
GenerateGame generateGame = new GenerateGame();
Newgame.addActionListener(switchMenu2);
Newgame.addActionListener(generateGame);
Sett.addActionListener(switchMenu1);
add(Sett);
}
class SwitchMenu1 implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
cl.show(container, "2");
}
}
class SwitchMenu2 implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
cl.show(container, "3");
}
}
class GenerateGame implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (checkexists == true){
grid = null;
grid = new JPanel();
}
try {
rownumber = Integer.parseInt(rows);
} catch (NumberFormatException be) {
rownumber = 10;
}
try {
columnnumber = Integer.parseInt(columns);
} catch (NumberFormatException be) {
columnnumber = 10;
}
Random rand = new Random();
int randomnumber;
String Letters = "AAIIOOUUEEABCDEFGHIJKLMNOPQRSTUVWXYZ";
grid.setLayout(new GridLayout(rownumber, columnnumber));
JButton[][] gridbutton = new JButton[rownumber][columnnumber];
MainbuttonAL mainbuttonAL = new MainbuttonAL();
for (int i = 0; i < rownumber; i++) {
for (int j = 0; j < columnnumber; j++) {
if (checkexists == true){
gridbutton[i][j] = null;
}
randomnumber = rand.nextInt(Letters.length());
gridbutton[i][j] = new JButton("" + Letters.charAt(randomnumber));
gridbutton[i][j].addActionListener(mainbuttonAL);
grid.add(gridbutton[i][j]);
}
}
mainGame.add(grid);
checkexists = true;
}
}
class MainbuttonAL implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
}
}
}
what method can i employ to regenerate a grid?

In general, you should be working on the concept of decoupling your views and your data, this means that you could have a "game model" which could be applied to a view and the view would then modify itself based on model properties, this is commonly known as "model - view - controller".
The problem is, however, you never remove grid from it's parent container when you create a new game
if (checkexists == true){
grid = null;
grid = new JPanel();
}
Instead, before you re-intialise the grid, you should remove from it's parent container
if (grid != null) {
mainGame.remove(grid);
grid = null;
grid = new JPanel();
}
or you could just remove the components from the grid panel itself
grid.removeAll();
A different approach...
At all stages you should be trying to decouple you objects and workflows from each other, so that it's easier to change any one part without having adverse effects on the other parts of the system or workflow.
Looking at you code, for example, the navigation decisions are tightly coupled to each panel/view, but in reality, they shouldn't know or care about how the navigation works (or the fact that there are other views), they should just do there job.
You can decouple this workflow through the use of delegation (backed by an observer). This basically means that the individual view doesn't care "how" the navigation works, only that when it makes a request for some action to be taken, it happens.
You should take the time to read through...
Model-View-Controller
Observer Pattern
Dependency Injection in Java
But how does this help you? Well, it will help you all the time!
Lets start with the "game" itself. The first thing we need is some kind of container to hold the data base logic for the game, so based on your current code, it might look something like...
public interface GameModel {
public int getRows();
public int getColumns();
}
I know, amazing isn't it, but this interface would grow to hold the logic required to run your game.
Now, we can apply this to the GamePanel
public class GamePane extends JPanel {
public interface Obsever {
public void back(GamePane source);
}
private GameModel model;
private Obsever obsever;
private JPanel contentPane;
private ActionListener buttonActionListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
didTap(e.getActionCommand());
}
};
public GamePane(Obsever obsever) {
this.obsever = obsever;
setLayout(new BorderLayout());
contentPane = new JPanel();
add(new JScrollPane(contentPane));
JButton backButton = new JButton("<< Back");
backButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
obsever.back(GamePane.this);
}
});
JPanel bannerPane = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.anchor = GridBagConstraints.LINE_END;
bannerPane.add(backButton, gbc);
add(bannerPane, BorderLayout.NORTH);
}
#Override
public Dimension getPreferredSize() {
// Bunch of things we could do here, but this basically
// acts as a stand in for CardLayout, otherwise the primary
// view will be to small
return new Dimension(800, 800);
}
public void setModel(GameModel model) {
if (this.model == model) {
// Do nothing, nothings changed
return;
}
this.model = model;
buildUI();
}
protected void buildUI() {
contentPane.removeAll();
if (model == null) {
return;
}
String Letters = "AAIIOOUUEEABCDEFGHIJKLMNOPQRSTUVWXYZ";
Random rnd = new Random();
JButton[][] gridbutton = new JButton[model.getRows()][model.getColumns()];
contentPane.setLayout(new GridLayout(model.getRows(), model.getColumns()));
//Game.MainMenu.MainbuttonAL mainbuttonAL = new Game.MainMenu.MainbuttonAL();
for (int i = 0; i < model.getRows(); i++) {
for (int j = 0; j < model.getColumns(); j++) {
int randomnumber = rnd.nextInt(Letters.length());
gridbutton[i][j] = new JButton("" + Letters.charAt(randomnumber));
//gridbutton[i][j].addActionListener(mainbuttonAL);
contentPane.add(gridbutton[i][j]);
}
}
}
protected void didTap(String action) {
}
}
Now, the nice "juicy" part is in the buildUI which is called by setModel when the model changes. This just re-builds the UI based on the GameModel properties.
As for the navigation concept, you can see part of it in the GamePane via its Observer interface. I started by creating a seperate class to handle the navigation workflows.
This means that the "how" or "implementation detail" is decoupled or hidden from the other parts of the system. Instead, it makes use of simple observer/delegation workflow.
Each view provides an Observer (for the what of a better name) which describes the navigation actions it needs performed. For example, both the SettingsPane and GamePane simply have back. They don't care what came before them, that's up to the navigation controller to decide.
public class NavigationPane extends JPanel {
enum View {
MAIN_MENU, GAME, SETTINGS
}
private CardLayout cardLayout;
private GameModel model;
private GamePane gamePane;
// Just for testing...
private Random rnd = new Random();
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
add(new MainMenu(new MainMenu.Observer() {
#Override
public void newGame(MainMenu source) {
gamePane.setModel(createModel());
navigateTo(View.GAME);
}
#Override
public void continueGame(MainMenu source) {
// Because it's possible to push continue
// without starting a game
// It might be possible have a "menu" model
// which can be used to change the enabled state of
// the continue button based on the state of the
// game
gamePane.setModel(getOrCreateGameModel());
navigateTo(View.GAME);
}
#Override
public void settingsGame(MainMenu source) {
navigateTo(View.SETTINGS);
}
}), View.MAIN_MENU);
gamePane = new GamePane(new GamePane.Obsever() {
#Override
public void back(GamePane source) {
navigateTo(View.MAIN_MENU);
}
});
add(gamePane, View.GAME);
add(new SettingsPane(new SettingsPane.Obsever() {
#Override
public void back(SettingsPane source) {
navigateTo(View.MAIN_MENU);
}
}), View.SETTINGS);
navigateTo(View.MAIN_MENU);
}
protected GameModel createModel() {
model = new DefaultGameModel(rnd.nextInt(9) + 2, rnd.nextInt(9) + 2);
return model;
}
protected GameModel getOrCreateGameModel() {
if (model == null) {
model = createModel();
}
return model;
}
protected void add(Component component, View view) {
add(component, view.name());
}
protected void navigateTo(View view) {
cardLayout.show(this, view.name());
}
}
Runnable example...
So, that's a lot of out-of-context code. The below is basically an example of one possible approach you could take to further reduce some of the clutter and coupling which is growing in your code base at this time.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new NavigationPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class NavigationPane extends JPanel {
enum View {
MAIN_MENU, GAME, SETTINGS
}
private CardLayout cardLayout;
private GameModel model;
private GamePane gamePane;
// Just for testing...
private Random rnd = new Random();
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
add(new MainMenu(new MainMenu.Observer() {
#Override
public void newGame(MainMenu source) {
gamePane.setModel(createModel());
navigateTo(View.GAME);
}
#Override
public void continueGame(MainMenu source) {
// Because it's possible to push continue
// without starting a game
// It might be possible have a "menu" model
// which can be used to change the enabled state of
// the continue button based on the state of the
// game
gamePane.setModel(getOrCreateGameModel());
navigateTo(View.GAME);
}
#Override
public void settingsGame(MainMenu source) {
navigateTo(View.SETTINGS);
}
}), View.MAIN_MENU);
gamePane = new GamePane(new GamePane.Obsever() {
#Override
public void back(GamePane source) {
navigateTo(View.MAIN_MENU);
}
});
add(gamePane, View.GAME);
add(new SettingsPane(new SettingsPane.Obsever() {
#Override
public void back(SettingsPane source) {
navigateTo(View.MAIN_MENU);
}
}), View.SETTINGS);
navigateTo(View.MAIN_MENU);
}
protected GameModel createModel() {
model = new DefaultGameModel(rnd.nextInt(9) + 2, rnd.nextInt(9) + 2);
return model;
}
protected GameModel getOrCreateGameModel() {
if (model == null) {
model = createModel();
}
return model;
}
protected void add(Component component, View view) {
add(component, view.name());
}
protected void navigateTo(View view) {
cardLayout.show(this, view.name());
}
}
public class MainMenu extends JPanel {
public interface Observer {
public void newGame(MainMenu source);
public void continueGame(MainMenu source);
public void settingsGame(MainMenu source);
}
private Observer observer;
public MainMenu(Observer observer) {
this.observer = observer;
setLayout(new GridBagLayout());
JButton newGameButton = new JButton("New Game");
JButton continueButton = new JButton("Continue");
JButton settingsButton = new JButton("Settings");
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.gridwidth = GridBagConstraints.REMAINDER;
add(newGameButton, gbc);
add(continueButton, gbc);
add(settingsButton, gbc);
newGameButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.newGame(MainMenu.this);
}
});
continueButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.continueGame(MainMenu.this);
}
});
settingsButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.settingsGame(MainMenu.this);
}
});
}
}
public class SettingsPane extends JPanel {
public interface Obsever {
public void back(SettingsPane source);
}
public SettingsPane(Obsever obsever) {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
add(new JLabel("All your setting belong to us"), gbc);
JButton backButton = new JButton("<< Back");
backButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
obsever.back(SettingsPane.this);
}
});
add(backButton, gbc);
}
}
public interface GameModel {
public int getRows();
public int getColumns();
}
public class DefaultGameModel implements GameModel {
private int rows;
private int columns;
public DefaultGameModel(int rows, int columns) {
this.rows = rows;
this.columns = columns;
}
#Override
public int getRows() {
return rows;
}
#Override
public int getColumns() {
return columns;
}
}
public class GamePane extends JPanel {
public interface Obsever {
public void back(GamePane source);
}
private GameModel model;
private Obsever obsever;
private JPanel contentPane;
private ActionListener buttonActionListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
didTap(e.getActionCommand());
}
};
public GamePane(Obsever obsever) {
this.obsever = obsever;
setLayout(new BorderLayout());
contentPane = new JPanel();
add(new JScrollPane(contentPane));
JButton backButton = new JButton("<< Back");
backButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
obsever.back(GamePane.this);
}
});
JPanel bannerPane = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.anchor = GridBagConstraints.LINE_END;
bannerPane.add(backButton, gbc);
add(bannerPane, BorderLayout.NORTH);
}
#Override
public Dimension getPreferredSize() {
// Bunch of things we could do here, but this basically
// acts as a stand in for CardLayout, otherwise the primary
// view will be to small
return new Dimension(800, 800);
}
public void setModel(GameModel model) {
if (this.model == model) {
// Do nothing, nothings changed
return;
}
this.model = model;
buildUI();
}
protected void buildUI() {
contentPane.removeAll();
if (model == null) {
return;
}
String Letters = "AAIIOOUUEEABCDEFGHIJKLMNOPQRSTUVWXYZ";
Random rnd = new Random();
JButton[][] gridbutton = new JButton[model.getRows()][model.getColumns()];
contentPane.setLayout(new GridLayout(model.getRows(), model.getColumns()));
//Game.MainMenu.MainbuttonAL mainbuttonAL = new Game.MainMenu.MainbuttonAL();
for (int i = 0; i < model.getRows(); i++) {
for (int j = 0; j < model.getColumns(); j++) {
int randomnumber = rnd.nextInt(Letters.length());
gridbutton[i][j] = new JButton("" + Letters.charAt(randomnumber));
//gridbutton[i][j].addActionListener(mainbuttonAL);
contentPane.add(gridbutton[i][j]);
}
}
}
protected void didTap(String action) {
}
}
}

Click Event - Accessing a boolean variable from another class [closed]

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Stuck on a problem that requires grabbing a boolean variable from another class.
I have the following for-loop, boolean and if-else statements
import java.awt.*;
import javax.swing.*;
import java.awt.Color.*;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import java.util.Random;
public class Checkers extends JFrame
{
Random random = new Random();
private final int ROWS = 2;
private final int COLS = 5;
private final int GAP = 2;
private final int NUM = ROWS * COLS;
private int i;
private int score;
private JPanel pane = new JPanel(new GridLayout(ROWS,COLS, GAP,GAP));
private JPanel pane2 = new JPanel();
private JPanel pane3 = new JPanel();
private JButton btn1 = new JButton("Play A Game");
private JButton btn2 = new JButton("Exit");
private JButton btn3 = new JButton("Easy");
private JButton btn4 = new JButton("Intermediate");
private JButton btn5 = new JButton("Difficult");
private JLabel lbl1 = new JLabel ("score: " + score);
private JLabel gameLost = new JLabel("You lose! You got: " + score + " points");
private JButton btnRestart = new JButton("Restart");
private MyPanel [] panel = new MyPanel[NUM];
private Color col1 = Color.RED;
private Color col2 = Color.WHITE;
private Color col3 = Color.GREEN;
private Color tempColor;
private boolean isPanelDisabled;
//Starts the checkers GUI, calling the constructor below this.
public static void main(String[] args){
new Checkers();
}
//Sets the dimensions of the GUI, visibility, background color and
//contents via the setBoard();
public Checkers()
{
super("Checkers");
setSize(600,600);
setVisible(true);
setBackground(Color.BLACK);
setBoard();
}
//Makes the grid, contains a conditional boolean, adds the panels to grid based on i value.
//sets Colours accordingly
public void setBoard()
{
boolean isPanelDisabled = false;
for (int i = 0; i < panel.length; i++) {
panel[i] = new MyPanel(this);
pane.add(panel[i]);
if (i % COLS == 0) {
tempColor = col1;
}
if (i == 9 || i <8) {
panel[i].setBackground(col1);
}
if(i == 8){
isPanelDisabled = true;
panel[i].setBackground(col3);
}
}
//pane background colour and the size of this pane.
pane.setBackground(Color.BLACK);
pane.setPreferredSize(new Dimension(300,300));
//pane background colour and size of this pane.
pane2.setBackground(Color.white);
pane2.setPreferredSize(new Dimension(300,300));
//directions on the board where these panes appear.
add(pane, BorderLayout.WEST);
add(pane2, BorderLayout.EAST);
pane2.add(lbl1);
pane2.add(btnRestart);
btnRestart.addActionListener( e -> restartBoard());
pane2.setLayout(new BoxLayout(pane2, BoxLayout.PAGE_AXIS));
}
//increments the score for the user based on current points.
public void incrementScore(){
if (score != 5){
score++;
lbl1.setText("Score: " + Integer.toString(score));
}
else if(score == 5){
lbl1.setText("Congratulations!, you've won!, your score is:" + score);
}
}
}
and this mouseClicked Event
import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JPanel;
public class MyPanel extends JPanel implements MouseListener, ActionListener {
private final Checkers checkers;
private boolean isPanelDisabled;
//MyPanel Constructor that initiates a instance of checkers.
public MyPanel(Checkers checkers) {
this.checkers = checkers;
addMouseListener(this);
}
#Override
public void actionPerformed(ActionEvent e){
}
// Sets the panel colours according to their int number and the boolean condiiton.
#Override
public void mouseClicked(MouseEvent e) {
if (isPanelDisabled == true){
setBackground(Color.CYAN);
}
else{
setBackground(Color.BLACK);
checkers.incrementScore();
}
}
My Expected result of this should be that if the user clicks the 8th panel in that grid, then the color of that panel will be cyan when pressed and not black, but it cant access the boolean variable? where am i going wrong here?

Your question involves communication between objects of different classes, and there are several ways to do this, but most basic is to call a method of an object in one class to the other.
First lets set up the problem,... I've created classes called MyPanel2 and Checkers2, to distinguish them from yours.
Say in MyPanel2 we have a Checkers2 field and a boolean field called selected that is set to false:
private Checkers2 checkers;
private boolean selected = false;
along with appropriate boolean getter and setter:
public void setSelected(boolean selected) {
this.selected = selected;
}
public boolean isSelected() {
return selected;
}
And say within the Checkers2 class you have a 10 instances of MyPanel2 held within an array, and you want the user to be able to "select" instances of the class, but only allow 7 of them to be selected, and assume that you want to user the set up that you're currently using, you could give the main class, a method, public boolean isPanelDisabled(), and have the MyPanel2 class call this method to determine if selection is allowed. So within MyPanel2 you could have a MouseListener with something like:
#Override
public void mousePressed(MouseEvent e) {
if (selected) {
return;
}
// call the Checkers2 boolean method to check
if (checkers.isPanelDisabled()) {
setBackground(DISABLED_COLOR);
} else {
setBackground(SELECTED_COLOR);
setSelected(true);
}
}
Within Checkers2 .isPanelDisabled() method you'd iterate through the array of MyPanel2 instances to see how many have been selected, something like this could work:
public boolean isPanelDisabled() {
int count = 0;
for (MyPanel2 panel2 : myPanels) {
if (panel2.isSelected()) {
count++;
}
}
return count >= MAX_COUNT;
}
The whole MCVE testable code could look like:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Checkers2 extends JFrame {
private static final int MAX_COUNT = 7;
private final int ROWS = 2;
private final int COLS = 5;
private final int GAP = 2;
private final int NUM = ROWS * COLS;
private MyPanel2[] myPanels = new MyPanel2[NUM];
public Checkers2() {
super("Checkers");
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel gridPanel = new JPanel(new GridLayout(ROWS, COLS, 1, 1));
gridPanel.setBackground(Color.BLACK);
gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
for (int i = 0; i < myPanels.length; i++) {
MyPanel2 myPanel = new MyPanel2(this);
gridPanel.add(myPanel);
myPanels[i] = myPanel;
}
JButton resetButton = new JButton("Reset");
resetButton.setMnemonic(KeyEvent.VK_R);
resetButton.addActionListener(evt -> {
for (MyPanel2 myPanel2 : myPanels) {
myPanel2.reset();
}
});
JButton exitButton = new JButton("Exit");
exitButton.setMnemonic(KeyEvent.VK_X);
exitButton.addActionListener(evt -> System.exit(0));
JPanel buttonPanel = new JPanel();
buttonPanel.add(resetButton);
add(gridPanel);
add(buttonPanel, BorderLayout.PAGE_END);
pack();
setLocationRelativeTo(null);
}
public boolean isPanelDisabled() {
int count = 0;
for (MyPanel2 panel2 : myPanels) {
if (panel2.isSelected()) {
count++;
}
}
return count >= MAX_COUNT;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new Checkers2().setVisible(true);
});
}
}
class MyPanel2 extends JPanel {
private static final int PREF_W = 200;
private static final int PREF_H = PREF_W;
private static final int GR = 240;
public static final Color BASE_COLOR = new Color(GR, GR, GR);
public static final Color DISABLED_COLOR = Color.CYAN;
public static final Color SELECTED_COLOR = Color.BLACK;
private Checkers2 checkers;
private boolean selected = false;
public MyPanel2(Checkers2 checkers) {
setBackground(BASE_COLOR);
this.checkers = checkers;
setPreferredSize(new Dimension(PREF_W, PREF_H));
addMouseListener(new MyMouse());
}
public void setSelected(boolean selected) {
this.selected = selected;
}
public boolean isSelected() {
return selected;
}
public void reset() {
setBackground(BASE_COLOR);
setSelected(false);
}
private class MyMouse extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
if (selected) {
return;
}
if (checkers.isPanelDisabled()) {
setBackground(DISABLED_COLOR);
} else {
setBackground(SELECTED_COLOR);
setSelected(true);
}
}
}
}
Another Option is to take all the logic out of MyPanel and put it into the main program, something like:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class Checkers3 extends JPanel {
private static final int MAX_COUNT = 7;
private final int ROWS = 2;
private final int COLS = 5;
private final int GAP = 2;
private final int NUM = ROWS * COLS;
private MyPanel3[] myPanels = new MyPanel3[NUM];
public Checkers3() {
JPanel gridPanel = new JPanel(new GridLayout(ROWS, COLS, 1, 1));
gridPanel.setBackground(Color.BLACK);
gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
MyMouse myMouse = new MyMouse();
for (int i = 0; i < myPanels.length; i++) {
MyPanel3 myPanel = new MyPanel3();
myPanel.addMouseListener(myMouse);
gridPanel.add(myPanel);
myPanels[i] = myPanel;
}
JButton resetButton = new JButton("Reset");
resetButton.setMnemonic(KeyEvent.VK_R);
resetButton.addActionListener(evt -> {
for (MyPanel3 myPanel : myPanels) {
myPanel.reset();
}
});
JButton exitButton = new JButton("Exit");
exitButton.setMnemonic(KeyEvent.VK_X);
exitButton.addActionListener(evt -> System.exit(0));
JPanel buttonPanel = new JPanel();
buttonPanel.add(resetButton);
setLayout(new BorderLayout());
add(gridPanel);
add(buttonPanel, BorderLayout.PAGE_END);
}
public boolean isPanelDisabled() {
int count = 0;
for (MyPanel3 panel : myPanels) {
if (panel.isSelected()) {
count++;
}
}
return count >= MAX_COUNT;
}
private class MyMouse extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
MyPanel3 myPanel = (MyPanel3) e.getSource();
if (myPanel.isSelected()) {
return; // it's already selected
} else if (isPanelDisabled()) {
myPanel.setSelected(false);
} else {
myPanel.setSelected(true);
}
}
}
private static void createAndShowGui() {
Checkers3 mainPanel = new Checkers3();
JFrame frame = new JFrame("Checkers");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
#SuppressWarnings("serial")
class MyPanel3 extends JPanel {
private static final int PREF_W = 200;
private static final int PREF_H = PREF_W;
private static final int GR = 240;
public static final Color BASE_COLOR = new Color(GR, GR, GR);
public static final Color DISABLED_COLOR = Color.CYAN;
public static final Color SELECTED_COLOR = Color.BLACK;
private boolean selected = false;
public MyPanel3() {
setBackground(BASE_COLOR);
setPreferredSize(new Dimension(PREF_W, PREF_H));
}
public void setSelected(boolean selected) {
this.selected = selected;
Color background = selected ? SELECTED_COLOR : DISABLED_COLOR;
setBackground(background);
}
public boolean isSelected() {
return selected;
}
public void reset() {
setSelected(false);
setBackground(BASE_COLOR);
}
}
But the BEST option is to put all logic within a separate model class (or classes) and make the GUI's as dumb as possible.

Fixing method latency in Java

Another problem, same program:
The following is MainGUI.java
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;
public class MainGUI extends JFrame implements ActionListener
{
private static final long serialVersionUID = 4149825008429377286L;
private final double version = 8;
public static int rows;
public static int columns;
private int totalCells;
private MainCell[] cell;
public static Color userColor;
JTextField speed = new JTextField("250");
Timer timer = new Timer(250,this);
String generationText = "Generation: 0";
JLabel generationLabel = new JLabel(generationText);
int generation = 0;
public MainGUI(String title, int r, int c)
{
rows = r;
columns = c;
totalCells = r*c;
System.out.println(totalCells);
cell = new MainCell[totalCells];
setTitle(title);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Timer set up
timer.setInitialDelay(Integer.parseInt(speed.getText()));
timer.setActionCommand("timer");
//set up menu bar
JMenuBar menuBar = new JMenuBar();
JMenu optionsMenu = new JMenu("Options");
JMenu aboutMenu = new JMenu("About");
menuBar.add(optionsMenu);
menuBar.add(aboutMenu);
JMenuItem helpButton = new JMenuItem("Help!");
helpButton.addActionListener(this);
helpButton.setActionCommand("help");
aboutMenu.add(helpButton);
JMenuItem aboutButton = new JMenuItem("About");
aboutButton.addActionListener(this);
aboutButton.setActionCommand("about");
aboutMenu.add(aboutButton);
JMenuItem colorSelect = new JMenuItem("Select a Custom Color");
colorSelect.addActionListener(this);
colorSelect.setActionCommand("colorSelect");
optionsMenu.add(colorSelect);
JMenuItem sizeChooser = new JMenuItem("Define a Custom Size");
sizeChooser.addActionListener(this);
sizeChooser.setActionCommand("sizeChooser");
optionsMenu.add(sizeChooser);
//Create text field to adjust speed and its label
JPanel speedContainer = new JPanel();
JLabel speedLabel = new JLabel("Enter the speed of a life cycle (in ms):");
speedContainer.add(speedLabel);
speedContainer.add(speed);
speedContainer.add(generationLabel);
Dimension speedDim = new Dimension(100,25);
speed.setPreferredSize(speedDim);
//Create various buttons
JPanel buttonContainer = new JPanel();
JButton randomizerButton = new JButton("Randomize");
randomizerButton.addActionListener(this);
randomizerButton.setActionCommand("randomize");
buttonContainer.add(randomizerButton);
JButton nextButton = new JButton("Next"); //forces a cycle to occur
nextButton.addActionListener(this);
nextButton.setActionCommand("check");
buttonContainer.add(nextButton);
JButton startButton = new JButton("Start");
startButton.addActionListener(this);
startButton.setActionCommand("start");
buttonContainer.add(startButton);
JButton stopButton = new JButton("Stop");
stopButton.addActionListener(this);
stopButton.setActionCommand("stop");
buttonContainer.add(stopButton);
JButton clearButton = new JButton("Clear");
clearButton.addActionListener(this);
clearButton.setActionCommand("clear");
buttonContainer.add(clearButton);
//holds the speed container and button container, keeps it neat
JPanel functionContainer = new JPanel();
BoxLayout functionLayout = new BoxLayout(functionContainer, BoxLayout.PAGE_AXIS);
functionContainer.setLayout(functionLayout);
functionContainer.add(speedContainer);
speedContainer.setAlignmentX(CENTER_ALIGNMENT);
functionContainer.add(buttonContainer);
buttonContainer.setAlignmentX(CENTER_ALIGNMENT);
//finish up with the cell container
GridLayout cellLayout = new GridLayout(rows,columns);
JPanel cellContainer = new JPanel(cellLayout);
cellContainer.setBackground(Color.black);
int posX = 0;
int posY = 0;
for(int i=0;i<totalCells;i++)
{
MainCell childCell = new MainCell();
cell[i] = childCell;
childCell.setName(String.valueOf(i));
childCell.setPosX(posX);
posX++;
childCell.setPosY(posY);
if(posX==columns)
{
posX = 0;
posY++;
}
cellContainer.add(childCell);
childCell.deactivate();
Graphics g = childCell.getGraphics();
childCell.paint(g);
}
//make a default color
userColor = Color.yellow;
//change icon
URL imgURL = getClass().getResource("images/gol.gif");
ImageIcon icon = new ImageIcon(imgURL);
System.out.println(icon);
setIconImage(icon.getImage());
//add it all up and pack
JPanel container = new JPanel();
BoxLayout containerLayout = new BoxLayout(container, BoxLayout.PAGE_AXIS);
container.setLayout(containerLayout);
container.add(cellContainer);
container.add(functionContainer);
add(menuBar);
setJMenuBar(menuBar);
add(container);
pack();
}
private void checkCells()
{
//perform check for every cell
for(int i=0;i<totalCells;i++)
{
cell[i].setNeighbors(checkNeighbors(i));
}
//use value from check to determine life
for(int i=0;i<totalCells;i++)
{
int neighbors = cell[i].getNeighbors();
if(cell[i].isActivated())
{
System.out.println(cell[i].getName()+" "+neighbors);
if(neighbors==0||neighbors==1||neighbors>3)
{
cell[i].deactivate();
}
}
if(cell[i].isActivated()==false)
{
if(neighbors==3)
{
cell[i].activate();
}
}
}
}
public void actionPerformed(ActionEvent e)
{
if(e.getActionCommand().equals("randomize"))
{
Random rn = new Random();
for(int i=0;i<totalCells;i++)
{
cell[i].deactivate();
if(rn.nextInt(6)==0)
{
cell[i].activate();
}
}
}
//help button, self-explanatory
if(e.getActionCommand().equals("help"))
{
JOptionPane.showMessageDialog(this, "The game is governed by four rules:\nFor a space that is 'populated':"
+ "\n Each cell with one or no neighbors dies, as if by loneliness."
+ "\n Each cell with four or more neighbors dies, as if by overpopulation."
+ "\n Each cell with two or three neighbors survives."
+ "\nFor a space that is 'empty' or 'unpopulated':"
+ "\n Each cell with three neighbors becomes populated."
+ "\nLeft click populates cells. Right click depopulates cells.","Rules:",JOptionPane.PLAIN_MESSAGE);
}
//shameless self promotion
if(e.getActionCommand().equals("about"))
{
JOptionPane.showMessageDialog(this, "Game made and owned by *****!"
+ "\nFree usage as see fit, but give credit where credit is due!\nVERSION: "+version,"About:",JOptionPane.PLAIN_MESSAGE);
}
//clears all the cells
if(e.getActionCommand().equals("clear"))
{
timer.stop();
generation = 0;
generationText = "Generation: "+generation;
generationLabel.setText(generationText);
for(int i=0;i<totalCells;i++)
{
cell[i].deactivate();
}
}
//starts timer
if(e.getActionCommand().equals("start"))
{
if(Integer.parseInt(speed.getText())>0)
{
timer.setDelay(Integer.parseInt(speed.getText()));
timer.restart();
}
else
{
JOptionPane.showMessageDialog(this, "Please use a value greater than 0!","Rules:",JOptionPane.ERROR_MESSAGE);
}
}
//stops timer
if(e.getActionCommand().equals("stop"))
{
timer.stop();
}
//run when timer
if(e.getActionCommand().equals("timer"))
{
generation++;
generationText = "Generation: "+generation;
generationLabel.setText(generationText);
timer.stop();
checkCells();
timer.setInitialDelay(Integer.parseInt(speed.getText()));
timer.restart();
}
//see checkCells()
if(e.getActionCommand().equals("check"))
{
generation++;
generationText = "Generation: "+generation;
generationLabel.setText(generationText);
checkCells();
}
//color select gui
if(e.getActionCommand().equals("colorSelect"))
{
userColor = JColorChooser.showDialog(this, "Choose a color:", userColor);
if(userColor==null)
{
userColor = Color.yellow;
}
}
//size chooser!
if(e.getActionCommand().equals("sizeChooser"))
{
SizeChooser size = new SizeChooser();
size.setLocationRelativeTo(null);
size.setVisible(true);
}
}
private int checkNeighbors(int c)
{
//if a LIVE neighbor is found, add one
int neighbors = 0;
if(cell[c].getPosX()!=0&&cell[c].getPosY()!=0)
{
if(c-columns-1>=0)
{
if(cell[c-columns-1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c-columns-1].getName());
neighbors++;
}
}
}
if(cell[c].getPosY()!=0)
{
if(c-columns>=0)
{
if(cell[c-columns].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c-columns].getName());
neighbors++;
}
}
}
if(cell[c].getPosX()!=columns-1&&cell[c].getPosY()!=0)
{
if(c-columns+1>=0)
{
if(cell[c-columns+1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c-columns+1].getName());
neighbors++;
}
}
}
if(cell[c].getPosX()!=0)
{
if(c-1>=0)
{
if(cell[c-1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c-1].getName());
neighbors++;
}
}
}
if(cell[c].getPosX()!=columns-1)
{
if(c+1<totalCells)
{
if(cell[c+1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c+1].getName());
neighbors++;
}
}
}
if(cell[c].getPosX()!=0&&cell[c].getPosY()!=rows-1)
{
if(c+columns-1<totalCells)
{
if(cell[c+columns-1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c+columns-1].getName());
neighbors++;
}
}
}
if(cell[c].getPosY()!=rows-1&&cell[c].getPosY()!=rows-1)
{
if(c+columns<totalCells)
{
if(cell[c+columns].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c+columns].getName());
neighbors++;
}
}
}
if(cell[c].getPosX()!=columns-1&&cell[c].getPosY()!=rows-1)
{
if(c+columns+1<totalCells)
{
if(cell[c+columns+1].isActivated())
{
System.out.println(cell[c].getName()+" found "+cell[c+columns+1].getName());
neighbors++;
}
}
}
return neighbors;
}
}
The following is MainCell.java:
public class MainCell extends JPanel implements MouseListener
{
//everything here should be self-explanatory
private static final long serialVersionUID = 1761933778208900172L;
private boolean activated = false;
public static boolean leftMousePressed;
public static boolean rightMousePressed;
private int posX = 0;
private int posY = 0;
private int neighbors = 0;
private URL cellImgURL_1 = getClass().getResource("images/cellImage_1.gif");
private ImageIcon cellImageIcon_1 = new ImageIcon(cellImgURL_1);
private Image cellImage_1 = cellImageIcon_1.getImage();
private URL cellImgURL_2 = getClass().getResource("images/cellImage_2.gif");
private ImageIcon cellImageIcon_2 = new ImageIcon(cellImgURL_2);
private Image cellImage_2 = cellImageIcon_2.getImage();
private URL cellImgURL_3 = getClass().getResource("images/cellImage_3.gif");
private ImageIcon cellImageIcon_3 = new ImageIcon(cellImgURL_3);
private Image cellImage_3 = cellImageIcon_3.getImage();
public MainCell()
{
Dimension dim = new Dimension(17, 17);
setPreferredSize(dim);
addMouseListener(this);
}
public void activate()
{
setBackground(MainGUI.userColor);
System.out.println(getName()+" "+posX+","+posY+" activated");
setActivated(true);
}
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
if(getPosX()==MainGUI.columns-1&&getPosY()==0)
{
//do nothing
}
else if(getPosY()!=0&&getPosX()!=MainGUI.columns-1)
{
g.drawImage(cellImage_1,0,0,null);
}
else if(getPosY()==0)
{
g.drawImage(cellImage_2,0,0,null);
}
else if(getPosX()==MainGUI.columns-1)
{
g.drawImage(cellImage_3,0,0,null);
}
}
public void setActivated(boolean b)
{
activated = b;
}
public void deactivate()
{
setBackground(Color.gray);
System.out.println(getName()+" "+posX+","+posY+" deactivated");
setActivated(false);
}
public boolean isActivated()
{
return activated;
}
public void setNeighbors(int i)
{
neighbors = i;
}
public int getNeighbors()
{
return neighbors;
}
public int getPosX()
{
return posX;
}
public void setPosX(int x)
{
posX = x;
}
public int getPosY()
{
return posY;
}
public void setPosY(int y)
{
posY = y;
}
public void mouseClicked(MouseEvent e)
{
}
public void mouseEntered(MouseEvent e)
{
if(leftMousePressed&&SwingUtilities.isLeftMouseButton(e))
{
activate();
}
if(rightMousePressed&&SwingUtilities.isRightMouseButton(e))
{
deactivate();
}
}
public void mouseExited(MouseEvent e)
{
}
public void mousePressed(MouseEvent e)
{
if(SwingUtilities.isRightMouseButton(e)&&!leftMousePressed)
{
deactivate();
rightMousePressed = true;
}
if(SwingUtilities.isLeftMouseButton(e)&&!rightMousePressed)
{
activate();
leftMousePressed = true;
}
}
public void mouseReleased(MouseEvent e)
{
if(SwingUtilities.isRightMouseButton(e))
{
rightMousePressed = false;
}
if(SwingUtilities.isLeftMouseButton(e))
{
leftMousePressed = false;
}
}
}
The following is SizeChooser.java:
import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import javax.swing.*;
public class SizeChooser extends JFrame
{
private static final long serialVersionUID = -6431709376438241788L;
public static MainGUI GUI;
private static Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
JTextField rowsTextField = new JTextField(String.valueOf((screenSize.height/17)-15));
JTextField columnsTextField = new JTextField(String.valueOf((screenSize.width/17)-10));
private static int rows = screenSize.height/17-15;
private static int columns = screenSize.width/17-10;
public SizeChooser()
{
setResizable(false);
setTitle("Select a size!");
JPanel container = new JPanel();
BoxLayout containerLayout = new BoxLayout(container, BoxLayout.PAGE_AXIS);
container.setLayout(containerLayout);
add(container);
JLabel rowsLabel = new JLabel("Rows:");
container.add(rowsLabel);
container.add(rowsTextField);
JLabel columnsLabel = new JLabel("Columns:");
container.add(columnsLabel);
container.add(columnsTextField);
JButton confirmSize = new JButton("Confirm");
confirmSize.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
GUI.setVisible(false);
GUI = null;
if(Integer.parseInt(rowsTextField.getText())>0)
{
rows = Integer.parseInt(rowsTextField.getText());
}
else
{
JOptionPane.showMessageDialog(rootPane, "Please use a value greater than 0!","Rules:",JOptionPane.ERROR_MESSAGE);
}
if(Integer.parseInt(columnsTextField.getText())>0)
{
columns = Integer.parseInt(columnsTextField.getText());
}
else
{
JOptionPane.showMessageDialog(rootPane, "Please use a value greater than 0!","Rules:",JOptionPane.ERROR_MESSAGE);
}
GUI = new MainGUI("The Game of Life!", rows, columns);
GUI.setLocationRelativeTo(null);
GUI.setVisible(true);
setVisible(false);
}
});
container.add(confirmSize);
URL imgURL = getClass().getResource("images/gol.gif");
ImageIcon icon = new ImageIcon(imgURL);
System.out.println(icon);
setIconImage(icon.getImage());
pack();
}
public static void main(String[]args)
{
GUI = new MainGUI("The Game of Life!", rows, columns);
GUI.setLocationRelativeTo(null);
GUI.setVisible(true);
}
}
So the problem now is, when the randomize button is pressed, or a large number of cells exist and then the timer is started, the cells aren't as snappy as they would be with less active cells. For example, with 100 columns and 50 rows, when the randomize button is pressed, one cell activates, then the next, then another, and so forth. Can I have them all activate at exactly the same time? Is this just a problem with too many things calculated at once? Would concurrency help?
QUICK EDIT: Is the swing timer the best idea for this project?

I havent read through your code completely but I am guessing that your listener methods are fairly computationally intensive and hence the lag in updating the display.

This simple test reveals that your randomize operation should be fairly quick:
public static void main(String args[]) {
Random rn = new Random();
boolean b[] = new boolean[1000000];
long timer = System.nanoTime();
for (int i = 0; i < b.length; i++) {
b[i] = rn.nextInt(6) == 0;
}
timer = System.nanoTime() - timer;
System.out.println(timer + "ns / " + (timer / 1000000) + "ms");
}
The output for me is:
17580267ns / 17ms
So this leads me into thinking activate() or deactivate() is causing your UI to be redrawn.
I am unable to run this because I don't have your graphical assets, but I would try those changes to see if it works:
In MainGUI#actionPerformed, change:
if(e.getActionCommand().equals("randomize"))
{
Random rn = new Random();
for(int i=0;i<totalCells;i++)
{
cell[i].deactivate();
if(rn.nextInt(6)==0)
{
cell[i].activate();
}
}
}
to:
if(e.getActionCommand().equals("randomize"))
{
Random rn = new Random();
for(int i=0;i<totalCells;i++)
{
// This will not cause the object to be redrawn and should
// be a fairly cheap operation
cell[i].setActivated(rn.nextInt(6)==0);
}
// Cause the UI to repaint
repaint();
}
Add this to MainCell
// You can specify those colors however you like
public static final Color COLOR_ACTIVATED = Color.RED;
public static final Color COLOR_DEACTIVATED = Color.GRAY;
And change:
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
if(getPosX()==MainGUI.columns-1&&getPosY()==0)
{
//do nothing
}
to:
protected void paintComponent(Graphics g)
{
// We now make UI changes only when the component is painted
setBackground(activated ? COLOR_ACTIVATED : COLOR_DEACTIVATED);
super.paintComponent(g);
if(getPosX()==MainGUI.columns-1&&getPosY()==0)
{
//do nothing
}

Game of Life in Java, Overpopulation but can't figure out why

This is homework. I included relevant code at the bottom.
Problem:
In an attempted to allow the user to resize the grid, the grid is now being drawn severely overpopuated.
Screen Shots:
"Overpopulation" -
http://i.imgur.com/zshAC6n.png
"Desired Population" -
http://i.imgur.com/5Rf6P42.png
Background:
It's a version of Conway's Game of Life. In class we completed 3 classes: LifeState which handles the game logic, LifePanel which is a JPanel that contains the game, and a driver that created a JFrame and added the LifePanel. The assignment was to develop it into a full GUI application with various requirements. My solution was to extend JFrame and do most of my work in that class.
Initializing the LifePanel outside of the actionlistener yields normal population, but intializing the LifePanel in the actionlistener "overpopulates" the grid.
Question: Why is the overpopulation occurring?
LifePanel class
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
public class LifePanel extends JPanel implements MouseListener
{
private int row;
private int col;
private int scale;
private LifeState life;
boolean state;
boolean wrap;
int delay;
Timer timer;
public LifePanel(int r, int c, int s, int d)
{
row = r;
col = c;
scale = s;
delay = d;
life = new LifeState(row,col);
Random rnd = new Random();
for(int i=0;i<row;i++)
for(int j=0;j<col;j++)
life.setCell(i,j,rnd.nextBoolean());
timer = new Timer(delay, new UpdateListener());
setPreferredSize( new Dimension(scale*row, scale*col));
addMouseListener(this);
timer.start();
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
for(int i=0;i<row;i++)
for(int j=0;j<col;j++)
if(life.getCell(i,j))
g.fillRect(scale*i,scale*j,scale,scale);
}
public int getRow() {
return row;
}
public void setRow(int row) {
this.row = row;
}
public int getCol() {
return col;
}
public void setCol(int col) {
this.col = col;
}
public int getScale() {
return scale;
}
public void setScale(int scale) {
this.scale = scale;
}
public int getDelay() {
return delay;
}
public void setDelay(int delay) {
this.delay = delay;
timer.setDelay(delay);
}
public void pauseGame(){
timer.stop();
}
public void playGame(){
timer.restart();
}
public void setInitState(boolean set){
state = set;
if(state){
timer.stop();
}
}
public void setWrap(boolean set){
wrap = set;
if(wrap){
//implement allow wrap
}
}
#Override
public void mouseClicked(MouseEvent e) {
if(state){
int x=e.getX();
int y=e.getY();
boolean isFilled;
isFilled = life.getCell(x,y);
//Test pop-up
JOptionPane.showMessageDialog(this, x+","+y+"\n"+life.getCell(x,y));
if(isFilled){
life.setCell(x,y,false);
}else{
life.setCell(x,y,true);
}
repaint();
}
}
#Override
public void mousePressed(MouseEvent e) {}
#Override
public void mouseReleased(MouseEvent e) {}
#Override
public void mouseEntered(MouseEvent e) {}
#Override
public void mouseExited(MouseEvent e) {}
private class UpdateListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
life.iterate();
repaint();
}
}
}
LifeFrame class
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class LifeFrame extends JFrame implements ActionListener{
JMenuBar menuBar;
JMenu mainMenu, helpMenu;
JMenuItem restartItem, quitItem, helpItem;
JButton stopButton, playButton, pauseButton, startButton;
CardLayout cardLayout = new MyCardLayout();
CardLayout cardLayout2 = new MyCardLayout();
SetupPanel setupPanel; //panel for input
LifePanel gamePanel; //game panel
JPanel controls = new JPanel(); //controls for game
JPanel controls2 = new JPanel(); //controls for input panel
JPanel cardPanel = new JPanel(cardLayout);
JPanel cardPanel2 = new JPanel(cardLayout2);
int gridRow=480;
int gridCol=480;
int scale=1;
int delay=2;
boolean setState = false;
boolean setWrap = false;
public LifeFrame() {
setTitle("Game of Life");
setLayout(new BorderLayout());
//Add the Panels
setupPanel = new SetupPanel();
gamePanel = new LifePanel(gridRow,gridCol,scale,delay);
cardPanel.add(setupPanel, "1");
cardPanel.add(gamePanel, "2");
add(cardPanel, BorderLayout.NORTH);
cardPanel2.add(controls2, "1");
cardPanel2.add(controls, "2");
add(cardPanel2, BorderLayout.SOUTH);
//init menu
menuBar = new JMenuBar();
//button listener setup
stopButton = new JButton("Stop");
pauseButton = new JButton("Pause");
playButton = new JButton("Play");
startButton = new JButton("Start");
stopButton.addActionListener(this);
pauseButton.addActionListener(this);
playButton.addActionListener(this);
startButton.addActionListener(this);
//menu listener setup
restartItem = new JMenuItem("Restart", KeyEvent.VK_R);
quitItem = new JMenuItem("Quit", KeyEvent.VK_Q);
helpItem = new JMenuItem("Help", KeyEvent.VK_H);
restartItem.addActionListener(this);
quitItem.addActionListener(this);
helpItem.addActionListener(this);
//add buttons
controls.add(stopButton);
controls.add(pauseButton);
controls.add(playButton);
controls2.add(startButton);
//build the menus
mainMenu = new JMenu("Menu");
mainMenu.setMnemonic(KeyEvent.VK_M);
helpMenu = new JMenu("Help");
helpMenu.setMnemonic(KeyEvent.VK_H);
menuBar.add(mainMenu);
menuBar.add(helpMenu);
setJMenuBar(menuBar);
//add JMenuItems
restartItem.getAccessibleContext().setAccessibleDescription("Return to setup screen");
mainMenu.add(restartItem);
mainMenu.add(quitItem);
helpMenu.add(helpItem);
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
pack();
setLocationRelativeTo(null);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent e) {
try{
gridRow = setupPanel.getRowSize();
gridCol = setupPanel.getColSize();
scale = setupPanel.getScale();
delay = setupPanel.getDelay();
setWrap = setupPanel.getSetWrap();
setState = setupPanel.getSetState();
}catch (NumberFormatException n){
JOptionPane.showMessageDialog(LifeFrame.this, "Make sure the fields contain only digits and are completed!");
return;
}
if(e.getSource() == pauseButton){
gamePanel.pauseGame();
}else if(e.getSource() == playButton){
gamePanel.playGame();
}else if(e.getSource() == quitItem){
System.exit(0);
}else if(e.getSource() == restartItem || e.getSource() == stopButton){
cardLayout.show(cardPanel, "1");
cardLayout2.show(cardPanel2, "1");
pack();
setLocationRelativeTo(null);
}else if(e.getSource() == helpItem){
String helpText = "Help\nPlease make sure every field is completed and contains only digits\nCurrent Stats:\nGrid Size: "+gamePanel.getRow()+" by "+gamePanel.getCol()+"\nScale: "+ gamePanel.getScale() +"\nDelay: "+gamePanel.getDelay()+"\nManual Initial State: "+setState+"\nEnable Wrapping: "+setWrap;
JOptionPane.showMessageDialog(LifeFrame.this, helpText);
}else if(e.getSource() == startButton){
gamePanel = new LifePanel(gridRow,gridCol,scale,delay);
cardPanel.add(gamePanel, "2");
/*
* Alternate solution, throws array index out of bounds due to array usage in the LifePanel, but properly
* populates the grid.
*
gamePanel.setRow(gridRow);
gamePanel.setCol(gridCol);
gamePanel.setScale(scale);
gamePanel.setDelay(delay);
*/
if(setWrap){
gamePanel.setWrap(true);
gamePanel.playGame();
}else if(setState){
gamePanel.setInitState(true);
}else{
gamePanel.setWrap(false);
gamePanel.setInitState(false);
gamePanel.playGame();
}
gamePanel.repaint();
cardLayout.show(cardPanel, "2");
cardLayout2.show(cardPanel2, "2");
pack();
setLocationRelativeTo(null);
}
}
public static class MyCardLayout extends CardLayout {
#Override
public Dimension preferredLayoutSize(Container parent) {
Component current = findCurrentComponent(parent);
if (current != null) {
Insets insets = parent.getInsets();
Dimension pref = current.getPreferredSize();
pref.width += insets.left + insets.right;
pref.height += insets.top + insets.bottom;
return pref;
}
return super.preferredLayoutSize(parent);
}
public Component findCurrentComponent(Container parent) {
for (Component comp : parent.getComponents()) {
if (comp.isVisible()) {
return comp;
}
}
return null;
}
}
}
Thanks for reading all this, and in advance for any help/advice you offer.
EDIT: Added screen shots and refined question.

Based on how you initialize LifePanel
Random rnd = new Random();
for(int i=0;i<row;i++)
for(int j=0;j<col;j++)
life.setCell(i,j,rnd.nextBoolean());
what you call "overpopulation" is the expected state. The above code will set about 1/2 of the cells to "alive" (or "occupied"), which is what your "overpopulated" state looks like.
The "desired population" screenshot contains many "life" artifacts such as "beehives", "gliders", "traffic lights", etc, and was either manually constructed or is the result of running several iterations on an initially 50% random population. With a 50% occupied population the first generation will result in wholesale clearing ("death") of many, many cells due to the proximity rules.
Most crucially, consider that, when starting up, your program does not paint the initial configuration. At least one iteration occurs before the first repaint() call.
I don't think your code is broken at all, just your expectation for what the initial population looks like.

Toggle read-only in Java

Is there a way to toggle a read-only mode so when you click any object in your window it simply returns what you clicked, ignoring the object's usual event handling? IE, while in this "read-only" mode, if you click on a Button, it simply returns the button, not actually pressing the button. Then I could do something like:
if ("thing pressed" == button) "do this";
else if ("thing pressed" == panel) "do that";
else "do nothing";
Here's my code, its a frame with 3 colored boxes. Clicking the 2nd box, the 3rd box, or the background will display a message. Clicking box 1 does nothing. I like using new mouse adapters so I want to do it this way.
Now what I want is when you click box 1, box 1 is treated as selected (if that helps you get the picture). Then if you click anywhere, including box 1 again, box 1 is deselected and nothing else (meaning that box 2, box 3. or the background's message will display). At that time, only if box 2 or 3 were clicked, they will still not display their normal message but a different message would be displayed.
I'm very sorry if I come off a little short.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Labels {
public static void main(String[] args) {
new Labels();
}
Square l1, l2, l3;
public Labels() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
l1 = new Square();
l2 = new Square();
l3 = new Square();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(120, 150);
frame.setResizable(false);
panel.setVisible(true);
panel.setLayout(null);
l1.setLocation(5, 5);
l2.setLocation(5, 60);
l3.setLocation(60, 5);
l2.setColor("yellow");
l3.setColor("black");
l1.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
//do nothing
}
});
l2.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("Pushed label 2");
}
});
l3.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("Pushed label 3");
}
});
panel.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("pushed background");
}
});
frame.add(panel);
panel.add(l1);
panel.add(l2);
panel.add(l3);
}
class Square extends JLabel{
Color color = Color.blue;
public Square() {
// TODO Auto-generated constructor stub\
setVisible(true);
setSize(50,50);
}
public void paint(Graphics g) {
super.paint(g);
g.setColor(color);
g.fillRect(0, 0, 50, 50);
}
public void setColor(String color){
if (color == "white") this.color = Color.white;
else if (color == "black") this.color = Color.black;
else if (color == "yellow") this.color = Color.yellow;
else {
System.out.println("Invalid color");
return;
}
repaint();
}
}
}

Don't disable anything. Simply change the state of your class, perhaps by using a few boolean flag variables/fields and change these flags depending on what is pressed.
So have boolean fields called label1PressedLast, label2PressedLast, and label3PressedLast or something similar, and when a label is pressed, check the states of all other flags and have your program's behavior change depending on the state of these flags and the label that was just pressed. Then set all flags to false except for the one corresponding to the label that was just pressed.
For example, this little program reacts only if the first and then the third JLabel have been pressed:
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.*;
public class FlagEg extends JPanel {
private static final int LABEL_COUNT = 3;
private JLabel[] labels = new JLabel[LABEL_COUNT];
private boolean[] flags = new boolean[LABEL_COUNT];
public FlagEg() {
setLayout(new GridLayout(1, 0, 20, 0));
setBorder(BorderFactory.createEmptyBorder(15, 15, 15, 15));
// panel mouse listener
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent arg0) {
inactivateAll();
}
});
MouseListener labelsMouseListener = new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mouseEvt) {
myMousePressed(mouseEvt);
}
};
// create JLabels and add MouseListener
for (int i = 0; i < labels.length; i++) {
labels[i] = new JLabel("Label " + (i + 1));
labels[i].addMouseListener(labelsMouseListener);
labels[i].setOpaque(true);
labels[i].setBorder(BorderFactory.createLineBorder(Color.black));
add(labels[i]);
}
}
private void inactivateAll() {
for (int i = 0; i < labels.length; i++) {
labels[i].setBackground(null);
flags[i] = false;
}
}
private void myMousePressed(MouseEvent mouseEvt) {
JLabel label = (JLabel) mouseEvt.getSource();
// which label was pressed?
int index = -1;
for (int i = 0; i < labels.length; i++) {
if (label == labels[i]) {
index = i;
}
}
// check if first label and then third pressed:
if (flags[0] && index == 2) {
System.out.println("first and then third label pressed!");
}
// reset all labels and flags to initial state
inactivateAll();
// set pressed label background color and set flag of label just pressed
labels[index].setBackground(Color.pink);
flags[index] = true;
}
private static void createAndShowGui() {
FlagEg mainPanel = new FlagEg();
JFrame frame = new JFrame("Flag Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Logic iteration two: only label 1 is the "primer" JLabel. This is actually easier to implement, because now you only need one boolean flag, that representing label 1 being pressed:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class FlagEg2 extends JPanel {
private static final int LABEL_COUNT = 3;
private JLabel[] labels = new JLabel[LABEL_COUNT];
private boolean label1Flag = false;
public FlagEg2() {
setLayout(new GridLayout(1, 0, 20, 0));
setBorder(BorderFactory.createEmptyBorder(15, 15, 15, 15));
// panel mouse listener
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent arg0) {
inactivateAll();
}
});
MouseListener labelsMouseListener = new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mouseEvt) {
myMousePressed(mouseEvt);
}
};
// create JLabels and add MouseListener
for (int i = 0; i < labels.length; i++) {
labels[i] = new JLabel("Label " + (i + 1));
labels[i].addMouseListener(labelsMouseListener);
labels[i].setOpaque(true);
labels[i].setBorder(BorderFactory.createLineBorder(Color.black));
add(labels[i]);
}
}
private void inactivateAll() {
for (int i = 0; i < labels.length; i++) {
labels[i].setBackground(null);
label1Flag = false;
}
}
private void myMousePressed(MouseEvent mouseEvt) {
JLabel label = (JLabel) mouseEvt.getSource();
// which label was pressed?
int index = -1;
for (int i = 0; i < labels.length; i++) {
if (label == labels[i]) {
index = i;
}
}
if (label1Flag) {
if (index == 1) {
System.out.println("Label 1 and label 2 pressed");
} else if (index == 2) {
System.out.println("Label 1 and label 3 pressed");
}
}
// reset all labels and flags to initial state
inactivateAll();
// if label1, then activate it
if (index == 0) {
labels[0].setBackground(Color.pink);
label1Flag = true;
}
}
private static void createAndShowGui() {
FlagEg2 mainPanel = new FlagEg2();
JFrame frame = new JFrame("Flag Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

package javaapplication6;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
*
* #author Jan Vorcak <vorcak#mail.muni.cz>
*/
public class Main {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
MouseListener listener = new MouseAdapter() {
private int count = 0;
#Override
public void mouseClicked(MouseEvent e) {
if(e.getComponent() instanceof JLabel) {
count++;
if (count >= 2) {
System.out.println("clicked 2 times on labels");
count = 0;
}
} else {
count = 0;
}
}
};
JFrame frame = new JFrame();
JPanel panel = new JPanel();
JLabel l1 = new JLabel("Label 1");
JLabel l2 = new JLabel("Label 2");
JLabel l3 = new JLabel("Label 3");
l1.addMouseListener(listener);
l2.addMouseListener(listener);
l3.addMouseListener(listener);
frame.addMouseListener(listener); // or panel.addMouseListener(listener);
panel.add(l1);
panel.add(l2);
panel.add(l3);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
}

You could want to create a listener that do the job for using the putClientProperty method of JComponent.
public class JComponentClickCountListener extends MouseAdapter {
private final Integer ONE = 1;
#Override
public void mouseClicked(MouseEvent e) {
if (e.getComponent() instanceof JComponent) {
JComponent jComponent = (JComponent) e.getComponent();
Object property = jComponent.getClientProperty(JComponentClickCountListener.class);
if (property instanceof Number) {
property = ONE + ((Number) property).intValue();
}
else {
property = ONE;
}
jComponent.putClientProperty(JComponentClickCountListener.class, property);
}
}
}
Then in your code you can decide to have a single instace of that class for all of your components or create a new one each time.
This could give you the advantage of using the propertyChangeListener for future actions.
PS.
The code example do not represent all logic for OP question but i could by used as solid base. Later on i will try to update it. To cover that.
EDIT2:
I think that you should separate the logic, of selection and action over selected items. Then the task is divided into two tasks. First is the possibility to store the information about it state, clicked active, clicked again inactive. The second tasks it to operate on that status when a jComponent status was changed.
This is an simple example that i wrote, the functionality is to highlight the background of labels when the are selected and remove it when it was clicked again or the panel was clicked remove all selections.
This example is divided to three elements Enum, Iterface and class that manage the logic of selection
Enum - we store the possible statuses and a property key.
public enum JComponentActivationStatus {
NONE,
ACTIVE,
INACTIVE;
public static final String PROPERTY_KEY = JComponentActivationStatus.class.getCanonicalName();
}
Interface - provide a delegate for action to be taken when jcomponenet status change.
public abstract interface JComponenetActivationStatusChangeAction<T extends JComponent> {
public abstract void onActivation(T object);
public abstract void onDeactivation(T object);
}
Class - This class mange the status logic of jcomponents.
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JComponent;
public class JComponenetActivationManager {
public static <T extends JComponent> T addMouseStatusControl(T jComponent) {
jComponent.addMouseListener(new JComponentMouseStatusModyfier());
return jComponent;
}
public static <T extends JComponent> T addActivationStatusChangeAction(T jComponenet, JComponenetActivationStatusChangeAction<T> statusChangeAction) {
jComponenet.addPropertyChangeListener(craeteJCompositeActivationStatusChangeListener(statusChangeAction));
return jComponenet;
}
public static <T extends JComponent> PropertyChangeListener craeteJCompositeActivationStatusChangeListener(JComponenetActivationStatusChangeAction<T> action) {
return new JComponentStatusPropertyChangeListener<T>(action);
}
/**
* Class that set the status for the JComponet after doubClicl
*/
private final static class JComponentMouseStatusModyfier extends MouseAdapter {
#Override
public void mouseClicked(MouseEvent e) {
if(e.getComponent() instanceof JComponent) {
JComponent jComponent = (JComponent) e.getComponent();
Object propertyValue = jComponent.getClientProperty(JComponentActivationStatus.PROPERTY_KEY);
if(JComponentActivationStatus.ACTIVE.equals(propertyValue)) { //We check that the ACTIVE status is already selected, if so we inactive.
propertyValue = JComponentActivationStatus.INACTIVE; //If so we inactive it.
} else {
propertyValue = JComponentActivationStatus.ACTIVE; // Otherwise we set it as active
}
jComponent.putClientProperty(JComponentActivationStatus.PROPERTY_KEY, propertyValue); // We use the property key form status
}
}
}
/**
* Help class that fire the actions after status is changed
*/
private static final class JComponentStatusPropertyChangeListener<T extends JComponent> implements PropertyChangeListener {
private final JComponenetActivationStatusChangeAction<T> statusChangeAction;
/**
*
*/
public JComponentStatusPropertyChangeListener(JComponenetActivationStatusChangeAction<T> statusChangeAction) {
if(statusChangeAction == null) {
throw new IllegalArgumentException("action can not be null at this point");
}
this.statusChangeAction = statusChangeAction;
}
#Override
public void propertyChange(PropertyChangeEvent evt) {
if(JComponentActivationStatus.PROPERTY_KEY.equals(evt.getPropertyName())) {
if(JComponentActivationStatus.ACTIVE.equals(evt.getNewValue())) {
statusChangeAction.onActivation((T) evt.getSource());
}
if(JComponentActivationStatus.INACTIVE.equals(evt.getNewValue())){
statusChangeAction.onDeactivation((T) evt.getSource());
}
}
}
}
}
That class contain two public static method, that allow the developer to add the functionality to mange status to any jComponent object, add subscribe the action handler if any change occur.
At the end we have the main method that test our solution
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
JLabel l1 = new JLabel("Label 1");
JLabel l2 = new JLabel("Label 2");
JLabel l3 = new JLabel("Label 3");
panel.setBackground(Color.CYAN);
addMouseStatusControl(panel);
addMouseStatusControl(l1);
addMouseStatusControl(l2);
addMouseStatusControl(l3);
JComponenetActivationStatusChangeAction<JLabel> activeBackground = new JComponenetActivationStatusChangeAction<JLabel>() {
#Override
public void onActivation(JLabel object) {
object.setOpaque(true);
object.setBackground(Color.YELLOW);
}
#Override
public void onDeactivation(JLabel object) {
object.setOpaque(false);
object.setBackground(object.getParent().getBackground());
}
};
JComponenetActivationStatusChangeAction<JPanel> deactivateChildrens = new JComponenetActivationStatusChangeAction<JPanel>() {
#Override
public void onDeactivation(JPanel object) {
}
#Override
public void onActivation(JPanel object) {
for(Component component : object.getComponents()) {
if(component instanceof JComponent) {
((JComponent) component).putClientProperty(JComponentActivationStatus.PROPERTY_KEY,JComponentActivationStatus.INACTIVE);
}
}
}
};
addActivationStatusChangeAction(l1, activeBackground);
addActivationStatusChangeAction(l2, activeBackground);
addActivationStatusChangeAction(l3, activeBackground);
addActivationStatusChangeAction(panel, deactivateChildrens);
panel.add(l1);
panel.add(l2);
panel.add(l3);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
The solution is very flexible and extendable in case you will need to add more labels.
The example is for those that want to learn. Any comment would be appreciate.