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Why wont this threading code work properly with the GUI? [Java Swing] [Threading]

My project uses Java Swing as a GUI. I am making a Towers of Hanoi game. I've just about got the GUI all working, but my solve command wont work properly.
Without threading calls, it immediately solves the towers as expected. I added a couple Thread.waits expected it to solve it step by step so the user can see how it does but instead, it waits some time, then solves the entire puzzle at once. I'm thinking it might not be repainting, but I'm not sure why. Does anyone know what is going on?
Heres the code for the solve:
public class Solver {
public Solver() {
// nothing
}
public void solve(
int numberBlocks,
int startPin,
int auxiliaryPin,
int endPin) {
if (numberBlocks == 1) {
movePin(startPin, endPin);
try {
Thread.sleep(200);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else {
solve(numberBlocks - 1, startPin, endPin, auxiliaryPin);
movePin(startPin, endPin);
try {
Thread.sleep(200);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
solve(numberBlocks - 1, auxiliaryPin, startPin, endPin);
}
}
private void movePin(int startPin, int endPin) {
TowersOfHanoiGame.moveTopBlock(startPin, endPin);
}
Here is the code from the GUI that does the work:
I know its terribly written, this is my first time writing with Java Swing, Im learning it as I go. If anyone has any pointers on how to better structure this, I'd love to hear about that also.
I'm pasting the whole class, but the important methods are initListeners, and moveTopBlock, and the methods they call.
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class TowersOfHanoiGame {
private static JFrame mainWindow;
private static JPanel mainContentPanel;
private static JPanel content;
private static ArrayList<Block> pegOneBlocks = new ArrayList<Block>();
private static ArrayList<Block> pegTwoBlocks = new ArrayList<Block>();
private static ArrayList<Block> pegThreeBlocks = new ArrayList<Block>();
private Color[] randomColors = new Color[8];
private Dimension menuSize = new Dimension(100, 100);
private static final int DISCSTEXTSIZE = 20;
private static final int MOVESTEXTSIZE = 30;
private ActionListener downButtonListener;
private ActionListener upButtonListener;
private ActionListener solveButtonListener;
private JLabel discs;
private JLabel moves;
private int discsNumber = 3;
private int movesNumber = 0;
private Solver solver = new Solver();
public TowersOfHanoiGame() {
// do nothing
initRandomColors();
initBlocks(3);
}
/**
* Initialize and display the game
*/
public void display() {
initListeners();
initWindow();
mainWindow.setVisible(true);
}
private void initListeners() {
downButtonListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
if (discsNumber > 3) {
discsNumber--;
updateLabels();
// clearContentFrame();
clearBlockArrays();
initBlocks(discsNumber);
reDrawContentFrame();
}
}
};
upButtonListener = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (discsNumber < 8) {
discsNumber++;
updateLabels();
// clearContentFrame();
clearBlockArrays();
initBlocks(discsNumber);
reDrawContentFrame();
}
}
};
solveButtonListener = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
solver.solve(discsNumber, 0, 1, 2);
}
};
}
private void updateLabels() {
discs.setText("DISCS: " + discsNumber);
moves.setText("MOVES: " + movesNumber);
}
/**
* Init the main window
*/
private void initWindow() {
mainWindow = new JFrame("Towers Of Hanoi");
initContentPanel();
mainWindow.setContentPane(mainContentPanel);
mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainWindow.setSize(1000, 1000);
mainWindow.setResizable(false);
mainWindow.getContentPane().setBackground(Color.WHITE);
}
/**
* Init the main content panel
*/
private void initContentPanel() {
mainContentPanel = new JPanel(new BorderLayout(50, 50));
JPanel menu = initMenuFrame();
content = initContentFrame();
mainContentPanel.add(menu, BorderLayout.PAGE_START);
mainContentPanel.add(content, BorderLayout.CENTER);
}
private static JPanel initContentFrame() {
JPanel ret = new JPanel(new BorderLayout());
JPanel pegs = new JPanel(new BorderLayout());
pegs.setBackground(Color.WHITE);
ret.setBackground(Color.WHITE);
Peg peg1 = new Peg(25, 500, 1.2);
Peg peg2 = new Peg(50, 500, 1.2);
Peg peg3 = new Peg(0, 500, 1.2);
peg1.addBlocks(pegOneBlocks);
peg2.addBlocks(pegTwoBlocks);
peg3.addBlocks(pegThreeBlocks);
pegs.add(peg1, BorderLayout.LINE_START);
pegs.add(peg2, BorderLayout.CENTER);
pegs.add(peg3, BorderLayout.LINE_END);
ret.add(pegs, BorderLayout.CENTER);
return ret;
}
private Color randomColor() {
int R = (int)(Math.random() * 256);
int G = (int)(Math.random() * 256);
int B = (int)(Math.random() * 256);
Color color = new Color(R, G, B); // random color, but can be bright or
// dull
// to get rainbow, pastel colors
Random random = new Random();
final float hue = random.nextFloat();
final float saturation = 0.9f;// 1.0 for brilliant, 0.0 for dull
final float luminance = 1.0f; // 1.0 for brighter, 0.0 for black
color = Color.getHSBColor(hue, saturation, luminance);
return color;
}
private void initRandomColors() {
for (int i = 0; i < 8; i++) {
randomColors[i] = randomColor();
}
}
private void initBlocks(int numBlocks) {
int startWidth = Block.LONGESTWIDTH;
for (int i = 0; i < numBlocks; i++) {
Block b = new Block((startWidth - (i * 15)), randomColors[i]);
pegOneBlocks.add(b);
}
}
private static void clearContentFrame() {
mainContentPanel.remove(content);
mainContentPanel.repaint();
}
private void clearBlockArrays() {
pegOneBlocks.clear();
pegTwoBlocks.clear();
pegThreeBlocks.clear();
}
public static void reDrawContentFrame() {
content = initContentFrame();
mainContentPanel.add(content, BorderLayout.CENTER);
mainContentPanel.repaint();
}
public static void moveTopBlock(int startPin, int destinationPin) {
Block b = null;
if (startPin == 0) {
b = pegOneBlocks.get(pegOneBlocks.size() - 1);
pegOneBlocks.remove(pegOneBlocks.size() - 1);
}
else if (startPin == 1) {
b = pegTwoBlocks.get(pegTwoBlocks.size() - 1);
pegTwoBlocks.remove(pegTwoBlocks.size() - 1);
}
else if (startPin == 2) {
b = pegThreeBlocks.get(pegThreeBlocks.size() - 1);
pegThreeBlocks.remove(pegThreeBlocks.size() - 1);
}
if (destinationPin == 0) {
pegOneBlocks.add(b);
}
else if (destinationPin == 1) {
pegTwoBlocks.add(b);
}
else if (destinationPin == 2) {
pegThreeBlocks.add(b);
}
reDrawContentFrame();
content.validate();
mainContentPanel.validate();
mainWindow.validate();
}
/**
* Build the menu panel
*
* #return menu panel
*/
private JPanel initMenuFrame() {
JPanel ret = new JPanel(new BorderLayout());
ret.setPreferredSize(menuSize);
// left
JPanel left = new JPanel(new FlowLayout());
left.setPreferredSize(menuSize);
JLabel label = new JLabel("DISCS: 3");
discs = label;
label.setFont(new Font("Serif", Font.BOLD, DISCSTEXTSIZE));
Button down = new Button("Decrease");
down.addActionListener(downButtonListener);
Button up = new Button("Increase");
up.addActionListener(upButtonListener);
left.add(label);
left.add(up);
left.add(down);
// mid
moves = new JLabel("MOVES: 0");
moves.setHorizontalAlignment(JLabel.CENTER);
moves.setFont(new Font("Serif", Font.BOLD, MOVESTEXTSIZE));
// right
JPanel right = new JPanel(new FlowLayout());
Button solve = new Button("Solve");
solve.addActionListener(solveButtonListener);
Button reset = new Button("Reset");
right.add(solve);
right.add(reset);
// sync
JPanel menu = new JPanel(new BorderLayout());
menu.add(left, BorderLayout.LINE_START);
menu.add(moves, BorderLayout.CENTER);
menu.add(right, BorderLayout.LINE_END);
ret.add(menu, BorderLayout.CENTER);
return ret;
}
}

solveButtonListener = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
solver.solve(discsNumber, 0, 1, 2);
}
};
The problem is that code invoked for any listener is executed on the Event Dispatch Thread (EDT). The EDT is responsible for responding to event and repaint the GUI. The Thread.sleep() method causes the EDT to sleep and as a result the GUI can't repaint itself until all the code has finished executing.
What you need to do is start a separate Thread when you invoke the solver.solve(...) method.
Read the section from the Swing tutorial on Concurrency for more information.
Note, the above suggestion to use a separate Thread is still not a proper solution. Swing was designed to be single Thread, which means that all updates to the state of your GUI and the repainting of the GUI should be done on the EDT. So this would mean you should also be using SwingUtilities.invokeLater() to add code to the EDT for processing. I have never tried doing this when using recursion, so I'm not sure the best way to do this.

Cant change java button color after resetting button array

Im creating a program in which I must from time to time reset a button Array and display it on a jPanel. The function below adds the jButtons to my panel and displays them perfectly the first time that it is called, but from then on, every time I call it (after emptying the jButton array and applying .removeAll() to the panel) it wont let me change the background color of the jButton. Some assistance to help me find out why this is would be great, thanks.
import java.awt.*;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import javafx.scene.layout.Border;
import javax.swing.*;
/**
*
* #author Luis
*/
public class MineSweeper extends JFrame implements ActionListener {
int int_dim = 11;
int int_cellsShown = 0;
JButton[][] arr_btnField = new JButton[int_dim][int_dim];
int[][] arr_solution = new int[int_dim][int_dim];
Color[] clr_palette = {Color.white, new Color(0X00, 0X94, 0XFF), new Color(0X00, 0X26, 0XFF), new Color(0X00, 0XAA, 0X0A), Color.red, Color.MAGENTA, new Color(0XFF, 0X00, 0X00), new Color(0X9B, 0X00, 0X00)};
boolean bool_change = false;
boolean bool_won = false;
boolean bool_firstround = false;
javax.swing.border.Border border = BorderFactory.createLineBorder(Color.darkGray, 1, true);
MenuBar menu_bar;
Menu menu;
MenuItem optionNew;
//boolean[][] arr_boolShowed=new boolean[int_dim][int_dim];
int int_mines = 8;
ArrayList<Integer> arl_field = new ArrayList<Integer>();
JPanel jpanel = new JPanel();
JPanel jpanel2 = new JPanel();
//ArrayList<Boolean> arl_boolShowed = new ArrayList<Boolean>();
/**
* #param args the command line arguments
*/
public MineSweeper() throws FontFormatException, IOException {
resetGame();
//JFrame frame = new JFrame("");
this.getContentPane().add(jpanel);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setResizable(true);
this.setTitle("Minesweeper");
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
this.setSize(500, 500);
menu_bar = new MenuBar();
menu = new Menu("File");
optionNew = new MenuItem("Win");
optionNew.addActionListener(this);
menu.add(optionNew);
menu_bar.add(menu);
this.setMenuBar(menu_bar);
}
public void resetGame() {
jpanel.removeAll();
arl_field.clear();
arr_btnField = new JButton[int_dim][int_dim];
arr_solution = new int[int_dim][int_dim];
bool_change = false;
bool_won = false;
//arl_field = new ArrayList<Integer>();
for (int i = 0; i < arr_solution.length; i++) {
for (int j = 0; j < arr_solution[i].length; j++) {
arr_solution[i][j] = 1;
}
}
jpanel.setLayout(new GridLayout(0, int_dim));//if(bool_firstround==false)jpanel.setLayout(new GridLayout(0,int_dim));
for (int i = 0; i < arr_btnField.length; i++) {
for (int j = 0; j < arr_btnField[i].length; j++) {
arr_btnField[i][j] = new JButton();////if(bool_firstround==false)arr_btnField[i][j] = new JButton();//arl_field.get(i*int_dim+j)+"");
arr_btnField[i][j].setText("");
arr_btnField[i][j].setBackground(new Color(0X00, 0X94, 0XFF));
arr_btnField[i][j].setBorder(border);
arr_btnField[i][j].setForeground(clr_palette[1]);
arr_btnField[i][j].addMouseListener(listener);
arr_btnField[i][j].setFocusable(false);
jpanel.add(arr_btnField[i][j]);
}
}
jpanel.revalidate();
jpanel.repaint();
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new MineSweeper();
UIManager.setLookAndFeel(
UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
}
});
}
MouseListener listener = new MouseListener() {
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mousePressed(MouseEvent e) {
outerloop:
for (int i = 0; i < arr_btnField.length; i++) {
for (int j = 0; j < arr_btnField[i].length; j++) {
if (e.getSource() == arr_btnField[i][j]) {
if (SwingUtilities.isLeftMouseButton(e)) {
labelText(i, j);
}
if (SwingUtilities.isRightMouseButton(e)) {
arr_btnField[i][j].setBackground(Color.red);
}
//bool_won=false;
break outerloop;
}
}
}
}
#Override
public void mouseReleased(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
if (bool_won == true)
gameWon();
}
#Override
public void mouseExited(MouseEvent e) {
}
};
public void labelText(int i, int j) {
if (bool_won == false) {
arr_btnField[i][j].setText("1");
arr_btnField[i][j].setBackground(Color.white);
if (arr_btnField[i][j].getBorder() == border) {
int_cellsShown++;
System.out.println("Cells shown: " + int_cellsShown);
if (int_cellsShown >= (int_dim * int_dim - int_mines)) {
bool_won = true;
}
}
if (bool_won == false)
arr_btnField[i][j].setBorder(BorderFactory.createLineBorder(Color.darkGray, 1, true));
}
}
public void gameWon() {
int dialogResult = JOptionPane.showConfirmDialog(null, "You Won! Do you want to start a new game?", "Congratulations!", JOptionPane.YES_NO_OPTION);
if (dialogResult == JOptionPane.YES_OPTION) {
bool_won = false;
int_cellsShown = 0;
resetGame();
}
}
#Override
public void actionPerformed(ActionEvent e) {
int_cellsShown = 0;
int_dim++;
resetGame();
for (int i = 0; i < arr_btnField.length; i++) {
for (int j = 0; j < arr_btnField[i].length; j++) {
arr_btnField[i][j].setBackground(Color.red);
}
}
}
}
Display after the first time:
Display after the second time:

I invoke .revalidate in the fourth line of the method.
That doesn't do anything since there on no components added to the panel. The revalidate() needs to be done AFTER the components have been added.
The displayed panel is not jpanel, the displayed panel is jpanel2, thats why I assign jpanel2 to the value of jpanel in the end of the method.
You can't just change a reference and expect the components to be moved from one panel to another.
The components need to be added to the panel that is added to the GUI.
Edit:
First of all Swing components start with "J". Don't use AWT components (MenuBar, Menu, MenuItem) in a Swing application.
The problem is your LAF:
new MineSweeper();
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
The components are created with the current LAF. When you first create the game, the default LAF is used to create all the buttons (and other components). This LAF allows you to change the background color of the buttons.
However, then you change the LAF. So when you reset the game board the buttons are now created with the System LAF. This LAF apparently does not allow you to change the background color of the button.
This should be easy to test. Create a GUI:
//UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
JButton button = new JButton("testing");
button.setBackground(Color.RED);
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( button );
frame.pack();
frame.setLocationByPlatform( true );
frame.setVisible( true );
First test the code as above to see if the background of the button changes.
Then uncomment the LAF change and retest.
A possible solution so you are not dependent on the LAF is to use an Icon to represent the background color of the button. Then you can center any text on top of the Icon. Something like:
import java.awt.*;
import javax.swing.*;
public class ColorIcon implements Icon
{
private Color color;
private int width;
private int height;
public ColorIcon(Color color, int width, int height)
{
this.color = color;
this.width = width;
this.height = height;
}
public int getIconWidth()
{
return width;
}
public int getIconHeight()
{
return height;
}
public void paintIcon(Component c, Graphics g, int x, int y)
{
g.setColor(color);
g.fillRect(x, y, width, height);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI()
{
JPanel panel = new JPanel( new GridLayout(2, 2) );
for (int i = 0; i < 4; i++)
{
Icon icon = new ColorIcon(Color.RED, 50, 50);
JLabel label = new JLabel( icon );
label.setText("" + i);
label.setHorizontalTextPosition(JLabel.CENTER);
label.setVerticalTextPosition(JLabel.CENTER);
panel.add(label);
}
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(panel);
f.setSize(200, 200);
f.setLocationRelativeTo( null );
f.setVisible(true);
}
}

Yep, I too just noticed, that the problem is here:
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new MineSweeper();
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
}
});
}
If you comment out the UIManager line, your code works. This line is only valid after the GUI has been created, and so doesn't take effect until new components are created. Note that I was working on minimizing your code to discover this, and was cutting out code to see what caused the problem until this was all that was left.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.UIManager;
#SuppressWarnings("serial")
public class MineSweeper extends JFrame implements ActionListener {
private static final Color BTN_COLOR = new Color(0X00, 0X94, 0XFF);
int int_dim = 11;
JButton[][] arr_btnField = new JButton[int_dim][int_dim];
JMenuBar menu_bar;
JMenu menu;
JMenuItem optionNew;
JPanel jpanel = new JPanel();
public MineSweeper() {
resetGame();
this.getContentPane().add(jpanel);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setResizable(true);
this.setTitle("Minesweeper");
menu_bar = new JMenuBar();
menu = new JMenu("File");
menu.setMnemonic(KeyEvent.VK_F);
optionNew = new JMenuItem("Win");
optionNew.setMnemonic(KeyEvent.VK_W);
optionNew.addActionListener(this);
menu.add(optionNew);
menu_bar.add(menu);
this.setJMenuBar(menu_bar);
this.setPreferredSize(new Dimension(500, 500));
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public void resetGame() {
jpanel.removeAll();
arr_btnField = new JButton[int_dim][int_dim];
jpanel.setLayout(new GridLayout(0, int_dim));
for (int i = 0; i < arr_btnField.length; i++) {
for (int j = 0; j < arr_btnField[i].length; j++) {
arr_btnField[i][j] = new JButton();
arr_btnField[i][j].setBackground(BTN_COLOR);
jpanel.add(arr_btnField[i][j]);
}
}
jpanel.revalidate();
jpanel.repaint();
}
#Override
public void actionPerformed(ActionEvent e) {
resetGame();
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new MineSweeper();
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
}
});
}
}

I get a stack overflow error

I'm trying to create a program where you press start and a new JFrame comes up with 3 buttons , you have to switch the button after you click on it using a random , I'm fairly new to java so I don't know what to do. Thank you
package code;
import java.awt.FlowLayout;
import java.awt.Font;
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.Timer;
public class StartListener implements java.awt.event.ActionListener {
private int counter;
private Game Ga;
private JFrame z;
private int x;
public StartListener(Game a, int co){
Ga=a;
counter = co;
}
public void actionPerformed(ActionEvent e) {
Timer time = new Timer(10000,new Time(Ga));
time.start();
z = new JFrame("Sequence game");
FlowLayout fl = new FlowLayout(0, 50, 40);
z.getContentPane().setLayout(fl);
z.setVisible(true);
JButton a = new JButton("A");
Font f = a.getFont();
Font myFont = f.deriveFont(Font.BOLD, f.getSize()*4);
a.setSize(200,100);
a.setVisible(true);
JButton b = new JButton("B");
b.setVisible(true);
b.setSize(200,100);
JButton c = new JButton("C");
c.setVisible(true);
c.setSize(200,100);
z.getContentPane().add(a);
z.getContentPane().add(b);
z.getContentPane().add(c);
z.pack();
Random r = new Random();
x=r.nextInt(3);
figure(a,b,c,x,myFont,f);}
public void figure(JButton a,JButton b, JButton c, int x, Font myFont,Font f){
if(x==0){
a.setEnabled(true);
b.setEnabled(false);
c.setEnabled(false);
a.setFont(myFont);
b.setFont(f);
c.setFont(f);
x =buttonA(a);
figure(a,b,c,x,myFont,f);
;}
else if(x==1){
a.setEnabled(false);
b.setEnabled(true);
c.setEnabled(false);
a.setFont(f);
c.setFont(f);
b.setFont(myFont);
x = buttonB(b);
figure(a,b,c,x,myFont,f);
}
else if(x==2){
a.setEnabled(false);
b.setEnabled(false);
c.setEnabled(true);
a.setFont(f);
b.setFont(f);
c.setFont(myFont);
x = buttonC(c);
figure(a,b,c,x,myFont,f);
}
}
public int buttonA(JButton a){
Random r = new Random();
int rand = 0;
a.addActionListener(new Something(Ga));
rand = r.nextInt(3);
return rand;
}
public int buttonB(JButton b){
Random r = new Random();
int rand = 0;
b.addActionListener(new Something(Ga));
rand=r.nextInt(3);
return rand;
}
public int buttonC(JButton c){
Random r = new Random();
int rand=0;
c.addActionListener(new Something(Ga));
rand = r.nextInt(3);
return rand;
}
}
And here's the code for Something
package code;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Something implements ActionListener {
private Game G;
public Something(Game a){
G = a;
}
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
G.increment();
}
}
Here's the error :
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at java.awt.Component.enable(Unknown Source)
at java.awt.Component.setEnabled(Unknown Source)
at javax.swing.JComponent.setEnabled(Unknown Source)
at javax.swing.AbstractButton.setEnabled(Unknown Source)

Your figure method continuously calls itself recursively forever, or until stack space runs out. Solution: get rid of those recursive calls. Also you really don't want to keep adding multiple ActionListeners on to JButtons, all this suggesting that you will want to refactor and perhaps redesign the entire program.
You will want to change the state of a field in the class, and use that field's state to decide what to do within the ActionListener.
For example:
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
#SuppressWarnings("serial")
public class SwapButtons extends JPanel {
private static final Font ACTIVE_FONT = new Font(Font.DIALOG, Font.BOLD, 15);
private static final String[] BTN_TEXT = { "Monday", "Tuesday", "Wednesday" };
private static final int EXTRA_WIDTH = 50;
private List<AbstractButton> buttonList = new ArrayList<>();
private int buttonIndex = 0;
public SwapButtons() {
setLayout(new GridLayout(1, 0, 5, 0));
BtnListener btnListener = new BtnListener();
for (int i = 0; i < BTN_TEXT.length; i++) {
JButton button = new JButton(BTN_TEXT[i]);
button.addActionListener(btnListener);
buttonList.add(button); // add to ArrayList
add(button); // add to GUI
}
setActiveButton();
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
}
#Override
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
// give preferred size extra width so gui can handle larger fonts
int prefW = superSz.width + EXTRA_WIDTH;
int prefH = superSz.height;
return new Dimension(prefW, prefH);
}
private void setActiveButton() {
// iterate through buttonList, turning on the "active" button
// as determined by the buttonIndex variable
for (int i = 0; i < buttonList.size(); i++) {
if (i == buttonIndex) {
buttonList.get(i).setFont(ACTIVE_FONT);
buttonList.get(i).setEnabled(true);
} else {
buttonList.get(i).setFont(null);
buttonList.get(i).setEnabled(false);
}
}
}
private class BtnListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
// show which button pressed
System.out.println("Button Pressed: " + e.getActionCommand());
// advance button index so that next button can be activated
buttonIndex++;
// but change index to 0 if buttonList size is reached
buttonIndex %= buttonList.size();
// activate the next button:
setActiveButton();
}
}
private static void createAndShowGui() {
SwapButtons mainPanel = new SwapButtons();
JFrame frame = new JFrame("Swap Buttons");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

Image did not fresh in Frame on Mouse Click In Java

First Time three random images shown on Jframe from three diffrent arrays.
even MouseClicked Method triggered but images does not refresh in Frame.
I want to refresh three random images each time i click on Frame.
Please help
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random;
import javax.swing.*;
public class Cards extends JFrame implements MouseListener {
public static void main(String[] args) {
JFrame frame = new Cards();
frame.setTitle("Cards");
frame.setSize(500, 500);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
new Cards();
}
public Cards() {
this.getContentPane().addMouseListener(this);
cards1();
cards2();
cards3();
}
public void cards1() {
ImageIcon[] images = new ImageIcon[10];
for (int i = 1; i < images.length; i++) {
images[i] = new ImageIcon("Drawables//Images//" + i + ".png");
}
int[] threeRandoms = new int[1];
Random ran = new Random();
for (int i = 0; i < threeRandoms.length; i++) {
threeRandoms[i] = ran.nextInt(10);
}
setLayout(new GridLayout(1, 4, 5, 5));
add(new JLabel(images[threeRandoms[0]]));
}
public void cards2() {
ImageIcon[] images = new ImageIcon[10];
for (int i = 1; i < images.length; i++) {
images[i] = new ImageIcon("Drawables//Images1//" + i + ".png");
}
int[] threeRandoms = new int[1];
Random ran = new Random();
for (int i = 0; i < threeRandoms.length; i++) {
threeRandoms[i] = ran.nextInt(10);
}
setLayout(new GridLayout(1, 4, 5, 5));
add(new JLabel(images[threeRandoms[0]]));
}
public void cards3() {
// this.getContentPane().addMouseListener(this);
ImageIcon[] images = new ImageIcon[10];
for (int i = 1; i < images.length; i++) {
images[i] = new ImageIcon("Drawables//Images2//" + i + ".png");
}
int[] threeRandoms = new int[1];
Random ran = new Random();
for (int i = 0; i < threeRandoms.length; i++) {
threeRandoms[i] = ran.nextInt(10);
}
// Labels with gridLayout
setLayout(new GridLayout(1, 4, 5, 5));
add(new JLabel(images[threeRandoms[0]]));
}
public void mouseClicked(MouseEvent e) {
System.out.println("The frame was clicked.");
new Cards();
}
public void mouseEntered(MouseEvent e) {
System.out.println("The mouse entered the frame.");
}
public void mouseExited(MouseEvent e) {
System.out.println("The mouse exited the frame.");
}
public void mousePressed(MouseEvent e) {
System.out.println("The left mouse button was pressed.");
}
public void mouseReleased(MouseEvent e) {
System.out.println("The left mouse button was released.");
}
}

I'm sorry, but I'm confused by your code. For one thing your cards1(), cards2() and cards3() methods look to be all the very same, and if so, why 3 different methods? Why not just one method? In those methods you appear to be trying to add JLabels repeatedly. Are you trying to add many many JLabels to the GUI? Or are you simply trying to display 3 images that change randomly on mouse action?
I would recommend structuring things a bit differently:
If possible, read all necessary images in once in your class's constructor, put the images into ImageIcons and then add them to an ArrayList or several ArrayLists if need be.
Don't add new JLabels each time a mouseClick occurs.
Create a JPanel give it a GridLayout and in your class constructor add to it three JLabels that are either instance fields or in an array or ArrayList.
Add this JPanel to your JFrame.
Add a MouseListener to each JLabel
in that MouseListener's mousePressed(MouseEvent e) method (not mouseClicked) randomize your number and use that number to call setIcon(...) on the JLabel source, obtained by calling getSource() on your MouseEvent parameter.
For example:
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
#SuppressWarnings("serial")
public class RandomImages extends JPanel {
private static final int LABEL_COUNT = 3;
private Random random = new Random();
public RandomImages() {
setLayout(new GridLayout(1, 3));
for (int i = 0; i < LABEL_COUNT; i++) {
final List<Icon> iconList = new ArrayList<>();
// TODO: get images for the ith list
// and fill iconList with ImageIcons from the first grouping
// create JLabel and give it the first Icon from the List above
final JLabel label = new JLabel(iconList.get(0));
label.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
// get random number from random object using iconList.size()
// get random Icon from list
// set label's icon via setIcon(...)
}
});
// add to GUI
add(label);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("RandomImages");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new RandomImages());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Concrete example 2:
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class RandomChessMen extends JPanel {
// for this example I get a sprite sheet that holds several sprite images in it
// the images can be found here: http://stackoverflow.com/questions/19209650
private static final String IMAGE_PATH = "http://i.stack.imgur.com/memI0.png";
private static final int LABEL_COUNT = 2;
private static final int ICON_COLUMNS = 6;
private Random random = new Random();
public RandomChessMen() throws IOException {
URL url = new URL(IMAGE_PATH);
BufferedImage largeImg = ImageIO.read(url);
setLayout(new GridLayout(1, 0));
// break down large image into its constituent sprites and place into ArrayList<Icon>
int w = largeImg.getWidth() / ICON_COLUMNS;
int h = largeImg.getHeight() / LABEL_COUNT;
for (int i = 0; i < LABEL_COUNT; i++) {
final List<Icon> iconList = new ArrayList<>();
int y = (i * largeImg.getHeight()) / LABEL_COUNT;
// get 6 icons out of large image
for (int j = 0; j < ICON_COLUMNS; j++) {
int x = (j * largeImg.getWidth()) / ICON_COLUMNS;
// get subImage
BufferedImage subImg = largeImg.getSubimage(x, y, w, h);
// create ImageIcon and add to list
iconList.add(new ImageIcon(subImg));
}
// create JLabel
final JLabel label = new JLabel("", SwingConstants.CENTER);
int eb = 40;
label.setBorder(BorderFactory.createEmptyBorder(eb, eb, eb, eb));
// get random index for iconList
int randomIndex = random.nextInt(iconList.size());
Icon icon = iconList.get(randomIndex); // use index to get random Icon
label.setIcon(icon); // set label's icon
label.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
Icon secondIcon = label.getIcon();
// so we don't repeat icons
while (label.getIcon() == secondIcon) {
int randomIndex = random.nextInt(iconList.size());
secondIcon = iconList.get(randomIndex);
}
label.setIcon(secondIcon);
}
});
// add to GUI
add(label);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("RandomImages");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
try {
frame.getContentPane().add(new RandomChessMen());
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

I have made these changes to your code:
Instead of having three methods cards1() cards2() cards3(), i have just made one cards() method.
Everytime you click on the frame, three random images get loaded.
I have set every image inside a JLabel in order to make it easy to update it.
The code below works perfectly according to your needs.
package example;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
public class Cards extends JFrame implements MouseListener {
JPanel subPanel1;
JLabel label1, label2, label3;
static ImageIcon[] images ;
static Random ran ;
static int[] threeRandoms;
public Cards() {
super("Cards");
subPanel1 = new JPanel();
// Set up first subpanel
subPanel1.setPreferredSize (new Dimension(400, 400));
//subPanel1.setBackground (Color.cyan);
label1 = new JLabel ("image 1",SwingConstants.CENTER);
label2 = new JLabel ("image 2", SwingConstants.LEFT);
label3 = new JLabel ("image 3", SwingConstants.CENTER);
subPanel1.add (label1);
subPanel1.add (label2);
subPanel1.add (label3);
add(subPanel1);
addMouseListener(this);
setSize(500, 500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setLocationRelativeTo(null);
setVisible(true);
System.out.println("Success.....");
}
public void cards() {
for (int i = 0; i < threeRandoms.length; i++)
threeRandoms[i] = ran.nextInt(3);
label1.setIcon(images[threeRandoms[0]]);
label2.setIcon(images[threeRandoms[1]]);
label3.setIcon(images[threeRandoms[2]]);
}
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("mouseClicked");
cards();
}
#Override
public void mouseEntered(MouseEvent e) {
System.out.println("mouseEntered");
}
#Override
public void mouseExited(MouseEvent e) {
System.out.println("mouseExited");
}
#Override
public void mousePressed(MouseEvent e) {
System.out.println("mousePressed");
}
#Override
public void mouseReleased(MouseEvent e) {
System.out.println("mouseReleased");
}
public static void loadImages(){
images = new ImageIcon[4];
ran = new Random();
threeRandoms = new int[3];
for (int i = 1; i <= images.length; i++) {
images[i-1] = new ImageIcon("Drawables//Images//" + i + ".png");
}
}
public static void main(String[] args) {
loadImages();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Cards();
}
});
}
}

Java Applet - For Loop to decrement a stack of components

I've created an Applet that creates a row of buttons, up to 15 buttons, when you push the "add to queue" button. I now want to decrement that row using a for loop. I want it to decrement from left to right. I can only get it to decrement from right to left. I know it has to do with the code in my "Remove" method, but I can't seem to figure out how to fix it. As a newbie I would appreciate any help you can provide.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Vector;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
public class Main extends javax.swing.JApplet {
private final int width = 60;
private final int height = 24;
private final int maxItems = 15;
private int x = 40 + width;
private int y = 260;
private int count = 1;
private JButton jAdd;
private JButton jRemove;
Vector<JButton> stack = new Vector<JButton>();
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
Main inst = new Main();
frame.getContentPane().add(inst);
((JComponent) frame.getContentPane()).setPreferredSize(inst
.getSize());
frame.pack();
frame.setVisible(true);
}
});
}
public Main() {
super();
initGUI();
}
private void initGUI() {
try {
this.setSize(719, 333);
getContentPane().setLayout(null);
{
jAdd = new JButton();
getContentPane().add(jAdd);
jAdd.setText("Add to Queue");
jAdd.setBounds(43, 300, 150, 24);
jAdd.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jAddActionPerformed(evt);
}
});
}
{
jRemove = new JButton();
getContentPane().add(jRemove);
jRemove.setText("Remove from queue");
jRemove.setBounds(950, 300, 150, 24);
jRemove.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jRemoveActionPerformed(evt);
}
});
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void jAddActionPerformed(ActionEvent evt) {
if (count > maxItems) {
JOptionPane.showMessageDialog(null, "The queue is full");
return;
}
JButton b = new JButton();
stack.add(0, b);
getContentPane().add(b);
int textCount = count;
b.setText("" +textCount++);
b.setBounds(x, y, width, height);
x = x + width;
count++;
}
private void jRemoveActionPerformed(ActionEvent evt) {
if (stack.isEmpty()) {
JOptionPane.showMessageDialog(null, "The queue is empty");
return;
}
JButton b = stack.remove(0);
this.remove(b);
for(int originalX = 880; originalX < 880; originalX--){
x = 880 - width;
}
repaint();
count--;
}
}

The issue is this:
stack.add(0, b);
You are always adding the new one to the start of the Vector (index 0). Remove that and you will see the behavior you want.
stack.add(b);