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amount of generated JLabels seems random on each start

I am trying generate a JLabel grid in Java, but on every start the generated JLabels vary, on one start of the program there can be 25 visual JLabels, and without changing the code and restarting there can be 27 visual JLabels, im so confused, I have no idea what might be causing this. In theory there should be 169 JLabels visual on the screen (13 x 13 grid).
public class GUI {
JFrame frame;
JPanel panel;
int matrixLength = 13;
JLabel label[] = new JLabel[matrixLength * matrixLength];
public GUI() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 600);
frame.setVisible(true);
frame.setResizable(false);
panel = (JPanel) frame.getContentPane();
panel.setLayout(null);
for (JLabel labels : label) {
labels = new JLabel();
labels.setVisible(true);
}
}
public void drawLabels() {
int xInc = 50;
int yInc = 50;
int xStart = 50;
int yStart = 0;
int y = yStart;
int x = 50;
for (int i = 0; i < label.length; i++) {
label[i] = new JLabel(" ");
label[i].setOpaque(true);
label[i].setVisible(true);
label[i].setBackground(Color.black);
if (i % (matrixLength) == 0) {
y += yInc;
x = xStart;
} else {
x += xInc;
}
System.out.println("i: " + i + " | y: " + y + " | x: " + x);
label[i].setBounds(x, y, 40, 40);
panel.add(label[i]);
}
}
}

I created the following GUI from your code.
Here are the changes I made.
I added a main method so I could start the application. In the main method, I called the SwingUtilities invokeLater method to ensure that the Swing components are created and executed on the Event Dispatch Thread.
I used two Swing layout managers to create the GUI. The JFrame has a default BorderLayout. The JPanel I created to hold the JLabels uses a GridLayout.
I added a text value to each of the JLabels so you could see them in the grid.
Here's the complete runnable code I used to create the GUI.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class LabelGridGUI {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new LabelGridGUI();
}
});
}
JFrame frame;
int matrixLength = 13;
JLabel label[] = new JLabel[matrixLength * matrixLength];
public LabelGridGUI() {
frame = new JFrame("Label Grid");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createLabelPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setResizable(false);
frame.setVisible(true);
}
public JPanel createLabelPanel() {
JPanel panel = new JPanel(new GridLayout(0, matrixLength));
for (int i = 0; i < label.length; i++) {
label[i] = new JLabel("X");
label[i].setBackground(Color.black);
label[i].setForeground(Color.yellow);
label[i].setOpaque(true);
panel.add(label[i]);
}
return panel;
}
}

In a 2D array of JButtons, how to change lines?

I am trying to create a 2D array of buttons but the buttons I created are all in the same line. I can change lines in 2D arrays of int and float by using System.out.println(). What should I so for buttons? (line 67 to 75)
As well, I don't know how to create actionListeners for buttons in a loop. Should I create a method for acctionLisener? Do they share the same action listener?
import java.awt.*;
import javax.swing.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JInternalFrame;
public class Hanoi {
private JFrame frame;
JButton[][] buttons= new JButton[3][3];
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Hanoi window = new Hanoi();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Hanoi() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 901, 696);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panelone = new JPanel();
frame.getContentPane().add(panelone, BorderLayout.CENTER);
panelone.setBackground(Color.WHITE);
GridBagLayout gbl_panelone = new GridBagLayout();
gbl_panelone.columnWidths = new int[]{0};
gbl_panelone.rowHeights = new int[]{0};
gbl_panelone.columnWeights = new double[]{Double.MIN_VALUE};
gbl_panelone.rowWeights = new double[]{Double.MIN_VALUE};
panelone.setLayout(gbl_panelone);
JPanel paneltwo = new JPanel();
frame.getContentPane().add(paneltwo, BorderLayout.NORTH);
paneltwo.setBackground(Color.WHITE);
JLabel lblFunHanoiTower = new JLabel("Fun Hanoi Tower");
lblFunHanoiTower.setForeground(Color.BLACK);
lblFunHanoiTower.setBackground(SystemColor.activeCaption);
lblFunHanoiTower.setFont(new Font("Viner Hand ITC", Font.PLAIN, 36));
paneltwo.add(lblFunHanoiTower);
//JButton[][] buttons = new JButton[3][3];
for(int row = 0; row < buttons.length ; row++) {
for(int col= 0; col < buttons[0].length ;col++) {
buttons[row][col] = new JButton(String.valueOf((row+3)+(col*3)));
buttons[row][col].setFont(new Font("Tempus Sans ITC", Font.BOLD, 16));
buttons[row][col].setBackground(SystemColor.controlHighlight);
buttons[row][col].setSize(66, 66);
panelone.add(buttons[row][col]);
}
}
}
}

Rather than modify your code, I have provided an example of GridLayout.
GridLayout divides the area of the JPanel into a grid, i.e. a table of rows and columns, where each "cell" in the grid can contain one component and each cell has the same size. Here is a complete, compilable and runnable example.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
public class Hanoi implements Runnable {
#Override // java.lang.Runnable
public void run() {
showGui();
}
private JPanel createGridPanel() {
// Number of rows will be calculated depending on total number
// of components added but each row will contain no more than
// three components.
GridLayout gridLayout = new GridLayout(0, 3);
JPanel gridPanel = new JPanel(gridLayout);
for (int row = 0; row < 3; row++) {
for (int col = 0; col < 3; col++) {
int number = (row + 3) + (col * 3);
String text = String.valueOf(number);
JButton button = new JButton(text);
gridPanel.add(button);
}
}
return gridPanel;
}
private void showGui() {
JFrame frame = new JFrame("Hanoi");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.add(createGridPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
Hanoi instance = new Hanoi();
EventQueue.invokeLater(instance);
}
}
And here is a screen capture of the running application.
(Note that I am using JDK 12 on Windows 10.)

You can use a grid layout, i change your original code (as you can see below). I recommend to use some designer for the gui, it more easy and clean. Net beans have a nice grafic interface builder.
public class Hanoi {
private JFrame frame;
JButton[][] buttons= new JButton[3][3];
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Hanoi window = new Hanoi();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Hanoi() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 901, 696);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panelone = new JPanel();
panelone.setLayout(new GridLayout(3,3));
frame.getContentPane().add(panelone);
panelone.setBackground(Color.WHITE);
/*GridBagLayout gbl_panelone = new GridBagLayout();
gbl_panelone.columnWidths = new int[]{0};
gbl_panelone.rowHeights = new int[]{0};
gbl_panelone.columnWeights = new double[]{Double.MIN_VALUE};
gbl_panelone.rowWeights = new double[]{Double.MIN_VALUE};*/
// panelone.setLayout(gbl_panelone);
JPanel paneltwo = new JPanel();
frame.getContentPane().add(paneltwo, BorderLayout.NORTH);
paneltwo.setBackground(Color.WHITE);
JLabel lblFunHanoiTower = new JLabel("Fun Hanoi Tower");
lblFunHanoiTower.setForeground(Color.BLACK);
lblFunHanoiTower.setBackground(SystemColor.activeCaption);
lblFunHanoiTower.setFont(new Font("Viner Hand ITC", Font.PLAIN, 36));
paneltwo.add(lblFunHanoiTower);
//JButton[][] buttons = new JButton[3][3];
for(int row = 0; row < buttons.length ; row++) {
for(int col= 0; col < buttons[0].length ;col++) {
buttons[row][col] = new JButton(String.valueOf((row+3)+(col*3)));
buttons[row][col].setFont(new Font("Tempus Sans ITC", Font.BOLD, 16));
buttons[row][col].setBackground(SystemColor.controlHighlight);
buttons[row][col].setSize(66, 66);
panelone.add(buttons[row][col]);
}
}
}
}

How to put 1 JPanel and 1 Custom JPanel in a JFrame

I want to have 2 JPanels in my app, side by side. One that will have some info about my custom board on the right and one about painting that custom board on the left. The first JPanel is a classic, but the second is a custom panel. It seems that im having problems with putting my custom panel into the frame.
I've created a class named BoardPanel within my gui class to draw my custom board. I don't know if this is the best approach. Should i create a separate class instead?
This is the code of the gui class:
public class BattleshipGUI extends JFrame {
private BoardPanel mainPanel;
///////////////////////////////////////////////////////////////////////////////////////////////
// Create my frame
///////////////////////////////////////////////////////////////////////////////////////////////
public BattleshipGUI() {
JPanel container = new JPanel(new BorderLayout()); //the container panel that contains the 2 other panels
mainPanel = new BoardPanel(); //main panel with my custom painting
JPanel detailsPanel = new JPanel(new BorderLayout()); //secondary panel with various details about the game
container.add(mainPanel, BorderLayout.CENTER); //add the 2 panels in the container
container.add(detailsPanel, BorderLayout.EAST);
this.add(container); //add container to my frame
//this.setContentPane(container);
this.setIconImage(Toolkit.getDefaultToolkit().getImage(BattleshipGUI.class.getResource("/resources/battleship_128.png")));
this.setTitle("My Battleship Game");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//this.setBounds(100, 100, 850, 700);
//this.pack();
this.setSize(850, 600);
this.setVisible(true);
}
And this is the code of the inner class for the custom painting
class BoardPanel extends JPanel {
private static final int ROWS = 20;
private static final int COLUMNS = 20;
public void paintComponent(Graphics g) {
super.paintComponent(g);
int sqSize = this.getHeight()/ROWS;
for(int i=0; i<ROWS; i++) {
for(int j=0; j<COLUMNS; j++) {
int x = j * sqSize;
int y = i * sqSize;
g.drawRect(x, y, sqSize, sqSize);
}
}
}
}
Aside from all these, i have a question. If i want to have a custom painting, is it possible to work along side with the WindowsBuilderPro? I begun using that tool at first. But, i saw that i cant draw something custom with the tool and i had to write code to do that. Is it possible to write code for a custom paint AND use the tool at the same time for different purposes, like adding a simple text label, or even to edit that custon paint? The expected result that i want to see, appears when i run the program. My frame with the two panels. But when i open the WindowsBuilderPro, my custom panel does not appear and the result is a bit wrong. Thit is the reason why i have a question about my approach and if i can write code and use the tool at the same time. Thank you and sorry for the long text guys. I am too confused about this.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = gbc.BOTH;
gbc.gridx = 0;
gbc.gridy = 0;
JPanel filler = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 300);
}
};
filler.setBackground(Color.BLUE);
add(filler, gbc);
gbc.gridx++;
add(new BoardPanel(), gbc);
}
}
class BoardPanel extends JPanel {
private static final int ROWS = 20;
private static final int COLUMNS = 20;
private int sqSize = 20;
#Override
public Dimension getPreferredSize() {
return new Dimension(COLUMNS * sqSize, ROWS * sqSize);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (int i = 0; i < ROWS; i++) {
for (int j = 0; j < COLUMNS; j++) {
int x = j * sqSize;
int y = i * sqSize;
g.drawRect(x, y, sqSize, sqSize);
}
}
}
}
}
Take the time to read through Laying Out Components Within a Container to get a better understanding how the layout management API works

JButtons won't update on button click

Currently displays a GUI with an 8x8 grid of randomized colored buttons. The newButton is to reset the score display to 0 and reset the grid with a fresh like it does on startup after being clicked. I haven't been able to find many solutions other than that it's to do with the way Java displays it's buttons and the way layering works. Here are the 2 classes I'm using.
import javax.swing.JFrame;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JPanel;
import java.awt.Color;
public class ShinyButtonsApp extends JFrame implements ActionListener {
private static byte ROWS = 8;
public int useThis;
ShinyButtons shiny = new ShinyButtons();
public static ImageIcon[] icons = {new ImageIcon("RedButton.png"),
new ImageIcon("OrangeButton.png"),
new ImageIcon("YellowButton.png"),
new ImageIcon("GreenButton.png"),
new ImageIcon("BlueButton.png"),
new ImageIcon("LightGrayButton.png"),
new ImageIcon("DarkGrayButton.png")};
public ShinyButtonsApp(String title) {
super(title); // Set title of window
setDefaultCloseOperation(EXIT_ON_CLOSE); // allow window to close
setSize(578, 634); // Set size of window
setResizable(false);
getContentPane().setLayout(null);
JLabel aLabel = new JLabel("Score: ");
aLabel.setLocation(10, 570);
aLabel.setSize(80,30);
getContentPane().add(aLabel);
JTextField scoreField = new JTextField();
scoreField.setText(Integer.toString(shiny.score));
scoreField.setEditable(false);
scoreField.setHorizontalAlignment(JTextField.RIGHT);
scoreField.setLocation(60, 570);
scoreField.setSize(120,30);
scoreField.setBackground(Color.WHITE);
getContentPane().add(scoreField);
JButton newButton = new JButton("New Game");
newButton.addActionListener(this);
newButton.setLocation(348,570);
newButton.setSize(110,30);
getContentPane().add(newButton);
JButton quitButton = new JButton("Quit");
quitButton.setLocation(468,570);
quitButton.setSize(80,30);
getContentPane().add(quitButton);
resetButtons2();
}
public void actionPerformed(ActionEvent e) {
shiny.score = 0;
shiny.resetButtons();
resetButtons2();
}
public void resetButtons2() {
for (int r=0; r<ROWS; r++) {
for (int c=0; c<ROWS; c++) {
ImageIcon image1 = icons[(int)shiny.getButton(r,c)];
JButton button = new JButton(image1);
button.setLocation(10+(69*r),10+(69*c));
button.setSize(69,69);
button.setBorder(BorderFactory.createLineBorder(Color.GRAY,1));
getContentPane().add(button);
}
}
}
public static void main(String[] args) {
ShinyButtonsApp frame;
frame = new ShinyButtonsApp("Shiny Buttons"); // Create window
frame.setVisible(true); // Show window
}
}
and
import javax.swing.JFrame;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JPanel;
import java.awt.Color;
public class ShinyButtons extends JPanel{
public static byte RED = 0;
public static byte ORANGE = 1;
public static byte YELLOW = 2;
public static byte GREEN = 3;
public static byte BLUE = 4;
public static byte LIGHT_GRAY = 5;
public static byte DARK_GRAY = 6;
public static byte ROWS = 8;
public byte[][] buttonTable;
public int score = 0;
public ShinyButtons() {
buttonTable = new byte[ROWS][ROWS];
resetButtons();
}
public void resetButtons() {
for (int r=0; r<ROWS; r++)
for (int c=0; c<ROWS; c++)
buttonTable[r][c] = (byte)(Math.random()*7);
}
public byte getButton(int r, int c) { return buttonTable[r][c]; }
public int getScore() { return score; }
}

Building on to what this answer points out (using layout managers instead of setting size, as you should be doing) you could reset the the images just by looping through the components (JLabels) of the JPanel and changing their icons.
This particular example uses JLabels with MouseListeners but it could easily be switched to JButtons with ActionListeners
newGame.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
reset(iconPanel, icons); <--- call reset method from below
score = 0;
scoreField.setText(String.valueOf(score));
}
});
....
private void reset(JPanel panel, ImageIcon[] icons) {
Component[] comps = panel.getComponents();
Random random = new Random();
for(Component c : comps) {
if (c instanceof JLabel) {
JLabel button = (JLabel)c;
int index = random.nextInt(icons.length);
button.setIcon(icons[index]);
}
}
}
Here's the complete running code. You just need to replace the image paths.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.border.LineBorder;
public class CircleImages {
private int score = 0;
private JTextField scoreField = new JTextField(10);
public CircleImages() {
scoreField.setEditable(false);
final ImageIcon[] icons = createImageIcons();
final JPanel iconPanel = createPanel(icons, 8);
JPanel bottomLeftPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));
bottomLeftPanel.add(new JLabel("Score: "));
bottomLeftPanel.add(scoreField);
JPanel bottomRightPanel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
JButton newGame = new JButton("New Game");
bottomRightPanel.add(newGame);
JButton quit = new JButton("Quit");
bottomRightPanel.add(quit);
JPanel bottomPanel = new JPanel(new GridLayout(1, 2));
bottomPanel.add(bottomLeftPanel);
bottomPanel.add(bottomRightPanel);
newGame.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
reset(iconPanel, icons);
score = 0;
scoreField.setText(String.valueOf(score));
}
});
JFrame frame = new JFrame();
frame.add(iconPanel);
frame.add(bottomPanel, BorderLayout.PAGE_END);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void reset(JPanel panel, ImageIcon[] icons) {
Component[] comps = panel.getComponents();
Random random = new Random();
for(Component c : comps) {
if (c instanceof JLabel) {
JLabel button = (JLabel)c;
int index = random.nextInt(icons.length);
button.setIcon(icons[index]);
}
}
}
private JPanel createPanel(ImageIcon[] icons, int gridSize) {
Random random = new Random();
JPanel panel = new JPanel(new GridLayout(gridSize, gridSize));
for (int i = 0; i < gridSize * gridSize; i++) {
int index = random.nextInt(icons.length);
JLabel label = new JLabel(icons[index]);
label.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e) {
score += 1;
scoreField.setText(String.valueOf(score));
}
});
label.setBorder(new LineBorder(Color.GRAY, 2));
panel.add(label);
}
return panel;
}
private ImageIcon[] createImageIcons() {
String[] files = {"blackcircle.png",
"bluecircle.png",
"greencircle.png",
"greycircle.png",
"orangecircle.png",
"redcircle.png",
"yellowcircle.png"
};
ImageIcon[] icons = new ImageIcon[files.length];
for (int i = 0; i < files.length; i++) {
icons[i] = new ImageIcon(getClass().getResource("/circles/" + files[i]));
}
return icons;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new CircleImages();
}
});
}
}

You are creating a new set of buttons in resetButtons2() and placing them on top (or rather under) of the already existing set of buttons in the same locations. You should create the set of buttons once and only update their icons upon reset.
You should do a number of things:
Use a proper layout manager, e.g., GridLayout
Create the 8x8 grid of buttons only once and replace their icons when needed
Call invalidate/repaint to refresh the content pane
And for a JFrame you don't need getContentPane().add(...), you can directly do add(...)

Two things.
First, make sure you remove the existing buttons first. Alternatively, you could simply update the state of the buttons. This would require you to create an array or List of buttons first, which your reset method would then iterate over and update their properties as required.
Second, make use of an appropriate layout manager. A null layout ias a very bad idea. You do not control the font metrics of the underlying platform and this will change how your buttons look on different systems, making your UI less dynamic then it should be

How to move a JPanel

I have a JDialog which contains JPanel and other elements like JTextField. I want to move JDialog from one location to another after it is loaded on screen. When I try to use jdialog.setLocation(), I am not able to move JDialog and also all other components added to it becomes invisible.
Can anyone tell me what might be wrong with my approach?

Regarding Gilbert's assertion that a dialog can't be moved after being set visible, please run this:
import java.awt.Component;
import java.awt.Dialog.ModalityType;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class MovingDialog {
private static void createAndShowGui() {
JPanel panel = new JPanel();
panel.add(new JButton(new ShowMovingDialogAction()));
JFrame frame = new JFrame("MovingDialog");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class ShowMovingDialogAction extends AbstractAction {
private JPanel panel = new JPanel();
public ShowMovingDialogAction() {
super("Show Moving Dialog");
panel.add(new JLabel("label"));
panel.add(new JTextField("TextField", 10));
panel.add(new JButton("Button"));
}
#Override
public void actionPerformed(ActionEvent e) {
JFrame owner = (JFrame) SwingUtilities.getWindowAncestor((Component) e
.getSource());
final JDialog dialog = new JDialog(owner, "Dialog",
ModalityType.APPLICATION_MODAL);
dialog.getContentPane().add(panel);
dialog.pack();
dialog.setLocation(0, 0);
int delay = 20;
new Timer(delay , new ActionListener() {
int x = 0;
int y = 0;
Dimension scrn = Toolkit.getDefaultToolkit().getScreenSize();
#Override
public void actionPerformed(ActionEvent e) {
int maxX = scrn.width - dialog.getWidth();
int maxY = scrn.height - dialog.getHeight();
if (x < maxX && y < maxY) {
x++;
y++;
dialog.setLocation(x, y);
} else {
((Timer)e.getSource()).stop();
}
}
}).start();
dialog.setVisible(true);
}
}
Note that the animation Swing Timer must be started before calling setVisible(true). Perhaps that is what Gilbert was referring to.

If you try to do animation then you will have to initialize and start a new thread and do it there. The code inside the run() method of the thread should check if the dialog is visible and call dialog.setLocation() with modified values on each iteration.