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Can't drag circles like example in book(Applet)

So my university uses the book Java programming from problem analysis to program design by DS Malik(ISBN: 978-1-111-53053-2) and in one of the examples I copied the code word for word. It runs but doesn't work the way its supposed too. What you're supposed to do is be able to click and drag circles that populate the screen in an applet. If anyone is interested in the programming example its 12-10. I have provided the code from eclipse. Any and all help is appreciated.
import javax.swing.*;
import java.awt.event.*;
import java.applet.*;
import java.awt.*;
public class FreeDrawApplet extends JApplet implements MouseMotionListener
{
//instance variables
ColorCircle[] myGraph;
final int NUM_CIRCLES = 7;
final int WIDTH = 400;
final int HEIGHT = 400;
public class ColorCircle
{
private int x;
private int y;
public void setx(int iNewX)
{
x = iNewX;
}
public void sety(int iNewY)
{
x = iNewY;
}
public void paint (Graphics g)
{
g.fillOval(x-10, y-10, 20, 20);
}
public boolean selected(int iXcoord, int iYcoord)
{
if ((iXcoord >= x-10) && (iXcoord <= x+10) && (iYcoord >= y-10) && (iYcoord <= y+10))
return true;
else
return false;
}
}//end of public class circle
public void init ()
{
addMouseMotionListener(this);
myGraph = new ColorCircle[NUM_CIRCLES];
for(int i = 0; i < NUM_CIRCLES; i++)
{
ColorCircle myVertex = new ColorCircle();
myVertex.setx((int)(Math.random() * (WIDTH-50)));
myVertex.sety((int)(Math.random() * (HEIGHT-100)));
myGraph[i] = myVertex;
}
JOptionPane.showMessageDialog(null, "Try to drag any one of the colored circles ", "Information", JOptionPane.PLAIN_MESSAGE);
}//end of method
public void paint(Graphics g)
{
Color[] myColor = {Color.black, Color.red, Color.blue, Color.green, Color.cyan, Color.orange, Color.yellow};
if(NUM_CIRCLES > 0)
for(int i =0; i < NUM_CIRCLES; i++)
{
g.setColor(myColor[i]);
myGraph[i].paint(g);
}
}//end of paint method
public void mouseDragged(MouseEvent event)
{
int iX = event.getX();
int iY = event.getY();
for(int i = 0; i < NUM_CIRCLES; i++)
{
if(myGraph[i].selected(iX, iY))
{
myGraph[i].setx(iX);
myGraph[i].sety(iY);
break;
}
}
repaint();
}
public void mouseMoved(MouseEvent p1)
{
}
}

Java - Add shape to frame

I create a JFrame, followed by a JPanel and the set the parameters. I have a JPanel called boardSquares where each square would be coloured later on.
Once I attempt to add the checker to the board, the board colours are re-arranged.
I have had numerous attempts to fix this but have not succeeded. I am also sure that there is a better way to do this. Below is some code. All help is appreciated!
public void paintComponent(Graphics g)
{
g.setColor(Color.BLUE);
g.fillOval(0, 0, 30, 30);
}
public static void checkerBoard()
{
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
boardSquares[i][j] = new JPanel();
if ((i + j) % 2 == 0)
{
boardSquares[i][j].setBackground(Color.BLACK);
}
else
{
boardSquares[i][j].setBackground(Color.WHITE);
}
frameOne.add(boardSquares[i][j]);
}
}
}

Look at this example https://www.javaworld.com/article/3014190/learn-java/checkers-anyone.html
And I've little bit upgrade your example
Sorry, I don't have much time for it
import java.awt.*;
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.Color;
import java.awt.Graphics;
public class Circle extends JPanel
{
public static JFrame frameOne = new JFrame("Frame 1");
public static Circle boardSquares[][] = new Circle[8][8];
public static void main(String[] args)
{
checkerBoard();
frameOne.setSize(new Dimension(400,400));
frameOne.getContentPane().setLayout(new GridLayout(8,8,0,0));
frameOne.setBackground(Color.BLACK);
frameOne.setVisible(true);
frameOne.setResizable(false);
frameOne.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
boardSquares[1][1].setChecker(true);
}
private Color c;
private boolean checker;
public Circle(int i, int j) {
super();
//setBorder(new Border());
//set
if ((i + j) % 2 == 0)
{
c = Color.DARK_GRAY;
}
else
{
c = Color.WHITE;
}
}
void setChecker(boolean ch) {
checker = ch;
}
public static void checkerBoard()
{
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
boardSquares[i][j] = new Circle(i, j);
frameOne.add(boardSquares[i][j]);
}
}
}
public void paintComponent(Graphics g)
{
g.setColor(c);
g.fillRect(0, 0, 40, 40);
if (checker) {
g.setColor(Color.BLUE);
g.fillOval(4, 4, 32, 32);
}
}
}

I would create a separate board class and override the paintComponent method to draw the actual grid.
Then I would give the board a grid layout and add panels to hold the checkers.
There is an issue with the margin of the checker, but that may be due to the size of the panels. You can mess around with this. I fixed this by applying a border layout to the panel.
Finally, avoid using "magic numbers". Try to declare some instance variables inside your classes and pass their value in via the constructor or some setter/mutator methods.
Application.java
package game.checkers;
import java.awt.*;
import java.lang.reflect.InvocationTargetException;
import javax.swing.SwingUtilities;
public class Application implements Runnable {
public static final String APP_NAME = "Checkers Game";
private GameFrame gameFrame;
private GameBoard checkerBoard;
#Override
public void run() {
initialize();
Checker redChecker = new Checker(50, Color.RED);
Checker greenChecker = new Checker(50, Color.GREEN);
Checker blueChecker = new Checker(50, Color.BLUE);
checkerBoard.placeChecker(redChecker, 1, 5);
checkerBoard.placeChecker(greenChecker, 2, 4);
checkerBoard.placeChecker(blueChecker, 3, 3);
redChecker.addMouseListener(new CheckerMouseListener(redChecker));
greenChecker.addMouseListener(new CheckerMouseListener(greenChecker));
blueChecker.addMouseListener(new CheckerMouseListener(blueChecker));
}
protected void initialize() {
gameFrame = new GameFrame(APP_NAME);
checkerBoard = new GameBoard(8, 8);
checkerBoard.setPreferredSize(new Dimension(400, 400));
gameFrame.setContentPane(checkerBoard);
gameFrame.pack();
gameFrame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Application());
} catch (InvocationTargetException | InterruptedException e) {
e.printStackTrace();
}
}
}
GameFrame.java
package game.checkers;
import javax.swing.JFrame;
public class GameFrame extends JFrame {
private static final long serialVersionUID = 6797487872982059625L;
public GameFrame(String title) {
super(title);
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
GameBoard.java
package game.checkers;
import java.awt.*;
import javax.swing.JPanel;
public class GameBoard extends JPanel {
private static final long serialVersionUID = 5777309661510989631L;
private static final Color[] DEFAULT_TILE_COLORS = new Color[] { Color.LIGHT_GRAY, Color.WHITE };
private BoardZone[][] zones;
private Color[] tileColors;
private int rows;
private int cols;
public int getRows() {
return rows;
}
public void setRows(int rows) {
this.rows = rows;
}
public int getCols() {
return cols;
}
public void setCols(int cols) {
this.cols = cols;
}
public GameBoard(int rows, int cols, Color[] tileColors) {
super();
this.rows = rows;
this.cols = cols;
this.tileColors = tileColors;
initialize();
}
public GameBoard(int rows, int cols) {
this(rows, cols, DEFAULT_TILE_COLORS);
}
protected void initialize() {
this.setLayout(new GridLayout(rows, cols, 0, 0));
generateZones();
}
private void generateZones() {
this.setLayout(new GridLayout(rows, cols, 0, 0));
this.zones = new BoardZone[rows][cols];
for (int row = 0; row < rows; row++) {
for (int col = 0; col < cols; col++) {
this.add(zones[row][col] = new BoardZone());
}
}
}
public void placeChecker(Checker checker, int row, int col) {
zones[row][col].add(checker);
}
public Checker getChecker(int row, int col) {
return (Checker) zones[row][col].getComponent(0);
}
public void removeChecker(Checker checker, int row, int col) {
zones[row][col].remove(checker);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
int tileWidth = this.getWidth() / cols;
int tileHeight = this.getHeight() / rows;
for (int row = 0; row < rows; row++) {
for (int col = 0; col < cols; col++) {
int x = col * tileWidth;
int y = row * tileHeight;
g.setColor(tileColors[(row + col) % 2]);
g.fillRect(x, y, tileWidth, tileHeight);
}
}
}
}
Checker.java
package game.checkers;
import java.awt.*;
import javax.swing.JComponent;
public class Checker extends JComponent {
private static final long serialVersionUID = -4645763661137423823L;
private int radius;
private Color color;
public int getRadius() {
return radius;
}
public void setRadius(int radius) {
this.radius = radius;
}
public Color getColor() {
return color;
}
public void setColor(Color color) {
this.color = color;
}
public String getHexColor() {
return String.format("#%06X", getColor() == null ? 0 : getColor().getRGB());
}
public Checker(int radius, Color color) {
super();
this.setPreferredSize(new Dimension(radius, radius));
this.radius = radius;
this.color = color;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (this.radius <= 0 || this.color == null) {
return; // Do not draw it.
}
g.setColor(this.color);
g.fillOval(0, 0, this.radius - 1, this.radius - 1);
}
}
BoardZone.java
package game.checkers;
import java.awt.BorderLayout;
import javax.swing.JPanel;
public class BoardZone extends JPanel {
private static final long serialVersionUID = 8710283269464564251L;
public BoardZone() {
this.setOpaque(false);
this.setLayout(new BorderLayout());
}
}
CheckerMouseListener.java
package game.checkers;
import java.awt.event.*;
public class CheckerMouseListener implements MouseListener {
private Checker target;
public CheckerMouseListener(Checker target) {
this.target = target;
}
private String getCheckerName() {
String hexCode = target.getHexColor();
switch (hexCode) {
case "#FFFF0000":
return "RED";
case "#FF00FF00":
return "GREEN";
case "#FF0000FF":
return "BLUE";
default:
return hexCode;
}
}
#Override
public void mouseReleased(MouseEvent e) {
System.out.println("Released click over " + getCheckerName() + " checker.");
}
#Override
public void mousePressed(MouseEvent e) {
System.out.println("Pressed on " + getCheckerName() + " checker.");
}
#Override
public void mouseExited(MouseEvent e) {
System.out.println("Finished hovering over " + getCheckerName() + " checker.");
}
#Override
public void mouseEntered(MouseEvent e) {
System.out.println("Began hovering over " + getCheckerName() + " checker.");
}
#Override
public void mouseClicked(MouseEvent e) {
System.out.println("Clicked on " + getCheckerName() + " checker.");
}
}

How Do I Make These JLabels of JButtons invisible

I have a class called BoardSquare that is an inherited class of JButton. Each of the BoardSquare objects is stored in an array BoardSquare[][] boardsquares. I have used the following code
BoardSquare.boardSquares[j][i].add(new JLabel((j+1)+":"+(i+1)));
to add labels to each of the squares in the array according to their coordinates. I need them to have these labels(I think) so that I can identify them and addActionListeners, etc. How do I make the JLabels invisible so they don't show up in my JFrame?
Alternatively, how can I make the JLabel of each button an instance variable so that I can call JLabel.setVisible(false) but still use them when I add action listeners?
EDIT: If anyone's interested, it's for a Checkers Game.
Here are my classes:
GameWindow
BoardSquare
Checker
MyListener

Thank you for the edit. If this were my application, I'd probably do things very differently including,
Use a grid of JLabels not JButtons. I see no need to use JButtons, and a problem in that the button would not be as visually appealing as other possible solutions.
Either give the JLabel cells or the containing JPanel a MouseListener,
Have the JPanel cells have no Icon and thus be empty if no checker is on them,
Or have them hold an ImageIcon of an appropriately colored checker if they are not empty.
You could even animate the GUI by using the glass pane to hold a JPanel with an appropriate checker ImageIcon that the user can drag.
Note that if you absolutely have to use JButtons, then don't add JLabels to them. Instead simply set the JButton's Icon to null or to an appropriate Checker ImageIcon.
Edit
For example, a bad code example as a proof of concept. Try compiling and running this.
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.util.EnumMap;
import java.util.Map;
import javax.swing.*;
#SuppressWarnings("serial")
public class Checkers extends JPanel {
public static final int SIDE_LENGTH = 60;
public static final int ROW_COUNT = 8;
private static final String ROW = "row";
private static final String COLUMN = "column";
private static final Color LIGHT_COLOR = new Color(210, 180, 140);
private static final Color DARK_COLOR = new Color(107, 68, 35);
private Map<Checker, Icon> checkerIconMap = new EnumMap<Checker, Icon>(
Checker.class);
private JLabel[][] labelGrid = new JLabel[ROW_COUNT][ROW_COUNT];
private Checker[][] checkerGrid = new Checker[ROW_COUNT][ROW_COUNT];
public Checkers() {
for (Checker checker : Checker.values()) {
checkerIconMap.put(checker, createCheckerIcon(checker));
}
setLayout(new GridLayout(ROW_COUNT, ROW_COUNT));
for (int row = 0; row < labelGrid.length; row++) {
for (int col = 0; col < labelGrid[row].length; col++) {
checkerGrid[row][col] = Checker.EMPTY;
JLabel gridCell = new JLabel(checkerIconMap.get(Checker.EMPTY));
gridCell.setOpaque(true);
gridCell.putClientProperty(ROW, row);
gridCell.putClientProperty(COLUMN, col);
Color c = row % 2 == col % 2 ? LIGHT_COLOR : DARK_COLOR;
gridCell.setBackground(c);
add(gridCell);
labelGrid[row][col] = gridCell;
}
}
for (int i = 0; i < labelGrid.length / 2 - 1; i++) {
for (int j = 0; j < labelGrid.length / 2; j++) {
int row = i;
int col = j * 2;
col += row % 2 == 0 ? 1 : 0;
labelGrid[row][col].setIcon(checkerIconMap.get(Checker.BLACK));
checkerGrid[row][col] = Checker.BLACK;
row = ROW_COUNT - row - 1;
col = ROW_COUNT - col - 1;
labelGrid[row][col].setIcon(checkerIconMap.get(Checker.RED));
checkerGrid[row][col] = Checker.RED;
}
}
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
private Icon createCheckerIcon(Checker checker) {
BufferedImage img = new BufferedImage(SIDE_LENGTH, SIDE_LENGTH,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = img.createGraphics();
g2.setColor(checker.getColor());
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int x = 3;
int y = x;
int width = SIDE_LENGTH - 2 * x;
int height = width;
g2.fillOval(x, y, width, height);
g2.dispose();
return new ImageIcon(img);
}
private class MyMouseAdapter extends MouseAdapter {
private int selectedRow = -1;
private int selectedCol = -1;
private Checker selectedChecker = null;
private JPanel glassPane = null;
private Point p = null;
private JLabel movingLabel = new JLabel(checkerIconMap.get(Checker.EMPTY));
public MyMouseAdapter() {
movingLabel.setSize(movingLabel.getPreferredSize());
movingLabel.setVisible(false);
}
#Override
public void mousePressed(MouseEvent e) {
p = e.getPoint();
for (int row = 0; row < labelGrid.length; row++) {
for (int col = 0; col < labelGrid[row].length; col++) {
JLabel gridCell = labelGrid[row][col];
if (gridCell == getComponentAt(p)) {
if (checkerGrid[row][col] != Checker.EMPTY) {
selectedRow = row;
selectedCol = col;
selectedChecker = checkerGrid[row][col];
checkerGrid[row][col] = Checker.EMPTY;
labelGrid[row][col].setIcon(checkerIconMap.get(Checker.EMPTY));
JRootPane rootPane = SwingUtilities.getRootPane(Checkers.this);
glassPane = (JPanel) rootPane.getGlassPane();
glassPane.setVisible(true);
glassPane.setLayout(null);
movingLabel.setIcon(checkerIconMap.get(selectedChecker));
movingLabel.setVisible(true);
glassPane.add(movingLabel);
int x = p.x - SIDE_LENGTH / 2;
int y = p.y - SIDE_LENGTH / 2;
movingLabel.setLocation(x, y);
}
}
}
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (selectedChecker == null) {
return;
}
p = e.getPoint();
if (!Checkers.this.contains(p)) {
// if mouse releases and is totally off of the grid
returnCheckerToOriginalCell();
clearGlassPane();
return;
}
for (int row = 0; row < labelGrid.length; row++) {
for (int col = 0; col < labelGrid[row].length; col++) {
JLabel gridCell = labelGrid[row][col];
if (gridCell == getComponentAt(p)) {
if (isMoveLegal(row, col)) {
checkerGrid[row][col] = selectedChecker;
labelGrid[row][col].setIcon(checkerIconMap.get(selectedChecker));
// todo: check for jumped pieces...
} else {
// illegal move
returnCheckerToOriginalCell();
}
}
}
}
clearGlassPane();
}
// this code would go in the model class
private boolean isMoveLegal(int row, int col) {
if (checkerGrid[row][col] != Checker.EMPTY) {
// trying to put a checker on another checker
returnCheckerToOriginalCell();
} else if (row == selectedRow && col == selectedCol) {
// trying to put checker back in same position
returnCheckerToOriginalCell();
} else if (row % 2 == col % 2) {
// invalid square
returnCheckerToOriginalCell();
} else {
// TODO: more logic needs to go here to test for a legal move
// and to remove jumped pieces
return true;
}
return false;
}
#Override
public void mouseDragged(MouseEvent e) {
if (selectedChecker == null || p == null) {
return;
}
p = e.getPoint();
int x = p.x - SIDE_LENGTH / 2;
int y = p.y - SIDE_LENGTH / 2;
movingLabel.setLocation(x, y);
}
private void clearGlassPane() {
glassPane.setVisible(false);
movingLabel.setVisible(false);
selectedChecker = null;
p = null;
selectedCol = -1;
selectedRow = -1;
}
private void returnCheckerToOriginalCell() {
checkerGrid[selectedRow][selectedCol] = selectedChecker;
labelGrid[selectedRow][selectedCol].setIcon(checkerIconMap.get(selectedChecker));
}
}
private static void createAndShowGui() {
Checkers mainPanel = new Checkers();
JFrame frame = new JFrame("JLabelGrid");
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();
}
});
}
}
class CheckerModel {
}
enum Checker {
EMPTY(new Color(0, 0, 0, 0)), RED(Color.red), BLACK(Color.black);
private Color color;
private Checker(Color color) {
this.color = color;
}
public Color getColor() {
return color;
}
}
Better Model-View example being worked on...

Instead of adding the new Jlabel() directly to the array , make an instance first then add that ... i guess this is done in a loop so for example :
JLabel lbl;
for(....) {
lbl = new JLabel(new JLabel((j+1)+":"+(i+1));
lbl.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt()){
// TODO here
}
});
BoardSquare.boardSquares[j][i].add(lbl);

Menu in a simple java game [closed]

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This question appears to be off-topic because it lacks sufficient information to diagnose the problem. Describe your problem in more detail or include a minimal example in the question itself.
Closed 9 years ago.
Improve this question
I created a GUI named Menu class for my Start, Help and Exit button. my problem is my game won't start, it hangs everytime I press the Start button. Can someone check my error and explain it to me because its my case study at school.
package spaceSip;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
public class Menu extends JFrame implements ActionListener
{
private JLabel titleL;
private JButton startB, helpB, exitB;
static JFrame frame1 = new JFrame();
public Menu()
{
frame1.setSize(500,250);
Container mainP = frame1.getContentPane();
mainP.setLayout(null);
titleL = new JLabel("WELCOME");
startB = new JButton("Start");
helpB = new JButton("Help");
exitB = new JButton("Exit");
mainP.add(titleL);
titleL.setFont(new Font("Chiller",Font.BOLD,50));
titleL.setBounds(100, 30, 200, 50);
mainP.add(startB);
startB.setMnemonic(KeyEvent.VK_S);
startB.setBounds(200, 80, 100, 20);
mainP.add(helpB);
helpB.setMnemonic(KeyEvent.VK_H);
helpB.setBounds(200, 100, 100, 20);
mainP.add(exitB);
exitB.setMnemonic(KeyEvent.VK_E);
exitB.setBounds(200, 120, 100, 20);
startB.addActionListener(this);
helpB.addActionListener(this);
exitB.addActionListener(this);
frame1.setVisible(true);
frame1.setResizable(false);
}
public void actionPerformed(ActionEvent e)
{
String key = e.getActionCommand();
if(key == "Start")
{
frame1.dispose();
new SpaceShipMain();
}
else if(key == "Help")
{
}
else
System.exit(0);
}
public static void main(String[]args)
{
new Menu();
}
}
package spaceSip;
import javax.swing.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class SpaceShipMain implements MouseListener
{
private JFrame background;
private SpaceShipPanel back;
public static boolean paused;
public static boolean crashed;
public static boolean started;
public static boolean playedOnce;
public boolean goingUp;
private double upCount;
public static int distance;
public static int maxDistance;
public final int XPOS;
public final int NUMRECS;
public final int RECHEIGHT;
public final int RECWIDTH;
private int moveIncrement;
private int numSmoke;
private ArrayList<SpaceShipImage> toprecs;
private ArrayList<SpaceShipImage> bottomrecs;
private ArrayList<SpaceShipImage> middlerecs;
private ArrayList<SpaceShipImage> smoke;
private SpaceShipImage helicopter;
public SpaceShipMain()
{
NUMRECS = 100;
RECHEIGHT = 70;
RECWIDTH = 30;
XPOS = 200;
playedOnce = false;
maxDistance = 0;
load(new File("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/Best.txt"));
initiate();
}
public void load(File file)
{
try
{
Scanner reader = new Scanner(file);
while(reader.hasNext())
{
int value = reader.nextInt();
if(value > maxDistance)
maxDistance = value;
}
}
catch(IOException i )
{
System.out.println("Error. "+i);
}
}
public void save()
{
FileWriter out;
try
{
out = new FileWriter("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/Best.txt");
out.write("" + maxDistance);
out.close();
}
catch(IOException i)
{
System.out.println("Error: "+i.getMessage());
}
}
public void initiate()
{
if(!playedOnce)
{
background = new JFrame("Space Ship Game");
background.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //closes the program when the window is closed
background.setResizable(false); //don't allow the user to resize the window
background.setSize(new Dimension(800,500));
background.setVisible(true);
back = new SpaceShipPanel("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/starfield.jpg");
background.add(back);
back.addMouseListener(this);
}
playedOnce = true;
goingUp = false;
paused = false;
crashed = false;
started = false;
distance = 0;
upCount = 0;
moveIncrement = 2;
numSmoke = 15;
toprecs = new ArrayList<SpaceShipImage>();
middlerecs = new ArrayList<SpaceShipImage>();
bottomrecs = new ArrayList<SpaceShipImage>();
smoke = new ArrayList<SpaceShipImage>();
helicopter = new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF",XPOS,200);
for(int x = 0; x < NUMRECS; x++)
toprecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,5));
for(int x = 0; x < NUMRECS; x++)
bottomrecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,410));
middlerecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid2.jpg",1392,randomMidHeight()));
middlerecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid2.jpg",1972,randomMidHeight()));
drawRectangles();
}
public void drawRectangles()
{
long last = System.currentTimeMillis();
long lastCopter = System.currentTimeMillis();
long lastSmoke = System.currentTimeMillis();
long lastSound = System.currentTimeMillis();
int firstUpdates = 0;
double lastDistance = (double)System.currentTimeMillis();
while(true)
{
if(!paused && !crashed && started && (double)System.currentTimeMillis() - (double)(2900/40) > lastDistance)
{
lastDistance = System.currentTimeMillis();
distance++;
}
if(!paused && !crashed && started && System.currentTimeMillis() - 10 > lastCopter)
{
lastCopter = System.currentTimeMillis();
updateCopter();
updateMiddle();
}
if(!paused && !crashed && started && System.currentTimeMillis() - 100 > last)
{
last = System.currentTimeMillis();
updateRecs();
}
if(!paused && !crashed && started && System.currentTimeMillis() - 75 > lastSmoke)
{
lastSmoke = System.currentTimeMillis();
if (firstUpdates < numSmoke)
{
firstUpdates++;
smoke.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",187,helicopter.getY()));
for(int x = 0; x < firstUpdates; x++)
smoke.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",smoke.get(x).getX() - 12, smoke.get(x).getY()));
}
else
{
for(int x = 0; x < numSmoke - 1; x++)
smoke.get(x).setY(smoke.get(x+1).getY());
smoke.set(numSmoke - 1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",187,helicopter.getY()));
}
}
back.updateImages(middlerecs,helicopter,smoke);
}
}
public void updateRecs()
{
for(int x = 0; x < (NUMRECS - 1); x++) //move all but the last rectangle 1 spot to the left
{
toprecs.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,toprecs.get(x+1).getY()));
bottomrecs.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,bottomrecs.get(x+1).getY()));
}
}
public void randomDrop()
{
toprecs.get(26).setY(toprecs.get(26).getY() + (463 - bottomrecs.get(26).getY()));
bottomrecs.get(26).setY(463);
}
public int randomMidHeight()
{
int max = 10000;
int min = 0;
for(int x = 0; x < NUMRECS; x++)
{
if(toprecs.get(x).getY() > min)
min = (int)toprecs.get(x).getY();
if(bottomrecs.get(x).getY() < max)
max = (int)bottomrecs.get(x).getY();
}
min += RECHEIGHT;
max -= (RECHEIGHT + min);
return min + (int)(Math.random() * max);
}
//moves the randomly generated middle rectangles
public void updateMiddle()
{
if(middlerecs.get(0).getX() > -1 * RECWIDTH)
{
middlerecs.set(0,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(0).getX() - (RECWIDTH/5), middlerecs.get(0).getY()));
middlerecs.set(1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(1).getX() - (RECWIDTH/5), middlerecs.get(1).getY()));
}
else
{
middlerecs.set(0,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(1).getX() - (RECWIDTH/5), middlerecs.get(1).getY()));
middlerecs.set(1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(0).getX() + 580,randomMidHeight()));
}
}
public boolean shoot()
{
for(int x = 3; x <= 7; x++)
if(helicopter.getY() >= bottomrecs.get(x).getY())
return true;
for(int y = 3; y <= 7; y++)
if(helicopter.getY() <= toprecs.get(y).getY())
return true;
for(int z = 0; z <= 1; z++)
if(isInMidRange(z))
return true;
return false;
}
public boolean isInMidRange(int num)
{
Rectangle middlecheck = new Rectangle((int)middlerecs.get(num).getX(),(int)middlerecs.get(num).getY(),RECWIDTH,RECHEIGHT);
Rectangle coptercheck = new Rectangle((int)helicopter.getX(),(int)helicopter.getY(),70,48); //asteroid X and y bump
return middlecheck.intersects(coptercheck);
}
public void crash()
{
crashed = true;
if(distance > maxDistance)
{
maxDistance = distance;
save();
}
int reply = JOptionPane.showConfirmDialog(null, " RESTART ?", "GAME OVER", JOptionPane.YES_NO_OPTION);
if(reply == JOptionPane.YES_OPTION)
initiate();
else
System.exit(0);
initiate();
}
//moves the spaceship
public void updateCopter()
{
upCount += .10;
if(goingUp)
{
if(upCount < 3.5)
helicopter.setPosition(XPOS,(double)(helicopter.getY() - (.3 + upCount)));
else
helicopter.setPosition(XPOS,(double)(helicopter.getY() - (1.2 + upCount)));
helicopter.setImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF");
}
else
{
if(upCount < 1)
helicopter.setPosition(XPOS,(double)(helicopter.getY() + upCount));
else
helicopter.setPosition(XPOS,(double)(helicopter.getY() + (1.2 + upCount)));
helicopter.setImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF");
}
if(shoot())
crash();
}
//Called when the mouse exits the game window
public void mouseExited(MouseEvent e)
{
paused = true;
}
//Called when the mouse enters the game window
public void mouseEntered(MouseEvent e)
{
}
//Called when the mouse is released
public void mouseReleased(MouseEvent e)
{
goingUp = false;
upCount = -1;
if(paused)
paused = false;
}
//Called when the mouse is pressed
public void mousePressed(MouseEvent e)
{
if (!started)
started = true;
goingUp = true;
upCount = 0;
}
//Called when the mouse is released
public void mouseClicked(MouseEvent e)
{
}
}
package spaceSip;
import java.awt.Image;
import javax.swing.ImageIcon;
public class SpaceShipImage
{
private Image image; //The picture
private double x; //X position
private double y; //Y position
//Construct a new Moving Image with image, x position, and y position given
public SpaceShipImage(Image img, double xPos, double yPos)
{
image = img;
x = xPos;
y = yPos;
}
//Construct a new Moving Image with image (from file path), x position, and y position given
public SpaceShipImage(String path, double xPos, double yPos)
{
this(new ImageIcon(path).getImage(), xPos, yPos);
//easiest way to make an image from a file path in Swing
}
//They are set methods. I don't feel like commenting them.
public void setPosition(double xPos, double yPos)
{
x = xPos;
y = yPos;
}
public void setImage(String path)
{
image = new ImageIcon(path).getImage();
}
public void setY(double newY)
{
y = newY;
}
public void setX(double newX)
{
x = newX;
}
//Get methods which I'm also not commenting
public double getX()
{
return x;
}
public double getY()
{
return y;
}
public Image getImage()
{
return image;
}
}
package spaceSip;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
class SpaceShipPanel extends JPanel
{
private Image background;
private ArrayList<SpaceShipImage> middle;
private SpaceShipImage copter;
private ArrayList<SpaceShipImage> smoke;
//Constructs a new ImagePanel with the background image specified by the file path given
public SpaceShipPanel(String img)
{
this(new ImageIcon(img).getImage());
//The easiest way to make images from file paths in Swing
}
//Constructs a new ImagePanel with the background image given
public SpaceShipPanel(Image img)
{
background = img;
Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
//Get the size of the image
//Thoroughly make the size of the panel equal to the size of the image
//(Various layout managers will try to mess with the size of things to fit everything)
setPreferredSize(size);
setMinimumSize(size);
setMaximumSize(size);
setSize(size);
middle = new ArrayList<SpaceShipImage>();
smoke = new ArrayList<SpaceShipImage>();
}
//This is called whenever the computer decides to repaint the window
//It's a method in JPanel that I've overwritten to paint the background and foreground images
public void paintComponent(Graphics g)
{
//Paint the background with its upper left corner at the upper left corner of the panel
g.drawImage(background, 0, 0, null);
//Paint each image in the foreground where it should go
for(SpaceShipImage img : middle)
g.drawImage(img.getImage(), (int)(img.getX()), (int)(img.getY()), null);
for(SpaceShipImage img : smoke)
g.drawImage(img.getImage(), (int)(img.getX()), (int)(img.getY()), null);
if(copter != null)
g.drawImage(copter.getImage(), (int)(copter.getX()), (int)(copter.getY()), null);
drawStrings(g);
}
public void drawStrings(Graphics g)
{
g.setColor(Color.WHITE);
g.setFont(new Font("Arial",Font.BOLD,20));
g.drawString("Distance: " + SpaceShipMain.distance,30,440);
g.setFont(new Font("Arial",Font.BOLD,20));
if (SpaceShipMain.distance > SpaceShipMain.maxDistance)
g.drawString("Best: " + SpaceShipMain.distance,650,440);
else
g.drawString("Best: " + SpaceShipMain.maxDistance,650,440);
if(SpaceShipMain.paused)
{
g.setFont(new Font("Chiller",Font.BOLD,72));
g.drawString("Paused",325,290);
g.setFont(new Font("Chiller",Font.BOLD,30));
g.drawString("Click to unpause.",320,340);
}
}
//Replaces the list of foreground images with the one given, and repaints the panel
public void updateImages(ArrayList<SpaceShipImage> newMiddle,SpaceShipImage newCopter,ArrayList<SpaceShipImage> newSmoke)
{
copter = newCopter;
middle = newMiddle;
smoke = newSmoke;
repaint(); //This repaints stuff... you don't need to know how it works
}
}

You compare Strings with equals(value equality) not with ==(reference equality). For more information read this previous question How do I compare strings in Java?
As #AndrewThompson always advice don't use NullLayout
Java GUIs might have to work on a number of platforms, on different
screen resolutions & using different PLAFs. As such they are not
conducive to exact placement of components. To organize the
components for a robust GUI, instead use layout managers, or
combinations of
them1, along
with layout padding & borders for white
space2.
As you say that your gui is blocked, that may be cause some of your execution code takes too more time and it's executed in the same thread as gui stuff (The Event Dispatch Thread). As you have a while(true) that's block the gui so use a SwingTimer for execute repeatidly task or if that code that takes long time execute it in a background thread using a Swing Worker. Here you have a complete example. When you perform custom painting you should override paintComponent and in first line you have to call super.paintComponent(..) to follow correct chaining. Read more in Painting in AWT-Swing.
Another error i see is that you are adding components after calling setVisible(true) without calling revalidate() repaint(). So i recommend to first add components to container then call setVisible(true) at final step.

Java: How to use double-buffering in the Snake game for smooth animation?

I am writing the Snake game. I am stuck with the animations, because I want to get smooth animation. I don't how to double buffer images so that to get double-buffering. What has to be done so that this becomes double-buffered?
I use main frame that extends JFrame, and here I add two JPanels - one for status bar and one for animation.
Here are the classes used for snake animation:
Player.class
package snake;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import javax.swing.ImageIcon;
public class Player
{
private int headSizeX;
private int headSizeY;
private int tailSizeX;
private int tailSizeY;
private int x;
private int y;
private int speed = 5;
private int snakeSize = 40;
private Image[] snake = new Image[5];
private ArrayList<Integer> X,Y;
private static int imageNr = 0;
private int c = 0;
private int tmp;
private boolean death = false;
static int player;
private static boolean inverse = false;
private boolean left = false;
private boolean right = false;
private boolean up = true;
private boolean down = false;
public Player()
{
initPlayer();
headSizeX = snake[0].getWidth(null);
headSizeY = snake[0].getHeight(null)-2;
tailSizeX = snake[4].getWidth(null);
tailSizeY = snake[4].getHeight(null);
System.out.println("tail: "+tailSizeX+" "+tailSizeY);
x = MainGamePanel.getSizeX()/2;
y= MainGamePanel.getSizeY()-130;
}
public void initPlayer()
{
int imgNr = 5;
X = new ArrayList<Integer>();
Y = new ArrayList<Integer>();
String name = "green";
switch (player)
{
case 1:
name = "green"; break;
case 2:
name = "red"; break;
case 3:
name = "blue"; break;
}
for (int nr = 1; nr <= imgNr; nr++)
{
snake[nr-1] = new ImageIcon("img/" +name+"/snake" +nr+".png").getImage();
}
X.add(MainGamePanel.getSizeX()/2);
Y.add( MainGamePanel.getSizeY()-200);
X.add( MainGamePanel.getSizeX()/2);
Y.add( MainGamePanel.getSizeX()/2+33);
for (int i = 2; i < snakeSize; i++) {
X.add( MainGamePanel.getSizeX()/2);
Y.add( MainGamePanel.getSizeX()/2 + i*20+13);
}
}
public void paint(Graphics g)
{
//g.drawImage(snake[imageNr], x,y,headSizeX,headSizeY,null);
for (int i = 0; i < snakeSize; i++) {
if (i == 0)
g.drawImage(snake[imageNr], X.get(i), Y.get(i), null);
else
g.drawImage(snake[4], X.get(i), Y.get(i), null);
}
/*g.drawImage(snake[4],x, y+headSizeY, tailSizeX, tailSizeY, null);
for (int i = 1;i<snakeSize;i++)
g.drawImage(snake[4],x, y+i*tailSizeY+headSizeY, tailSizeX, tailSizeY, null);*/
}
public void update()
{
y = MainGamePanel.getSizeY()-headSizeY - 35;
for (int i = snakeSize-1; i > 0; i--) {
X.set(i, X.get(i-1));
Y.set(i, Y.get(i-1));
}
if (left) {
tmp = X.get(0);
X.set(0, tmp-20);
imageNr = 3;
}
if (right) {
tmp = X.get(0);
X.set(0, tmp+20);
imageNr = 1;
}
if (up) {
tmp = Y.get(0);
Y.set(0, tmp-20);
imageNr = 0;
}
if (down) {
tmp = Y.get(0);
Y.set(0, tmp+20);
imageNr = 2;
}
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if ((key == KeyEvent.VK_LEFT) && (!right)) {
left = true;
up = false;
down = false;
System.out.println("LEWO");
}
if ((key == KeyEvent.VK_RIGHT) && (!left)) {
right = true;
up = false;
down = false;
System.out.println("PRAWO");
}
if ((key == KeyEvent.VK_UP) && (!down)) {
up = true;
right = false;
left = false;
System.out.println("GÓRA");
}
if ((key == KeyEvent.VK_DOWN) && (!up)) {
down = true;
right = false;
left = false;
System.out.println("DÓŁ");
}
}
public void collision()
{
death = true;
}
public void reset()
{
imageNr = 0;
death = false;
}
public void setInverse(boolean set)
{
inverse = set;
}
public void increaseSpeed(int inc)
{
speed += inc;
}
public void decreaseSpeed(int dec)
{
speed -=dec;
}
public int getSnakeSize()
{
return snakeSize;
}
public void increaseSnakeSize()
{
snakeSize += 1;
}
public void decreaseSnakeSize(int dec)
{
snakeSize -= dec;
}
}
MainGamePanel.class
package snake;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class MainGamePanel extends JPanel implements KeyListener{
private Image bounds;
private Player player;
public static int sizex;
private Image tail;
private Image background;
private int lives;
private int speed;
private int levels;
private int counter = 0;
private int appleCounter = 0;
private static int level = 1;
public static int sizeX = 784;
public static int sizeY = 617;
public static int applesNumber;
private boolean gameover = false;
private boolean gameend = false;
private boolean death = false;
private boolean levelCompleted = false;
private Graphics buffer;
private BufferedImage img;
public MainGamePanel(int[] settings)
{
lives = settings[0];
speed = settings[1];
levels = settings[2];
bounds = new ImageIcon("img/bounds.jpg").getImage();
setFocusable(true);
addKeyListener(this);
//new Apple();
}
public void init()
{
player = new Player();
img = new BufferedImage(sizeX, sizeY, 2);
Levels.getLevel(1);
this.applesNumber = Levels.getApplesNumber();
this.background = new ImageIcon("img/bg/" + Levels.getBackground()).getImage();
}
public void addNotify()
{
super.addNotify();
init();
}
public void paintComponent(Graphics g){
super.paintComponent(g);
buffer = img.getGraphics();
buffer.drawImage(background, 0,0, sizeX, sizeY, null);
player.paint(buffer);
for (int i = 0; i <= getWidth(); i += 12) {
buffer.drawImage(bounds, i, 0, this);
buffer.drawImage(bounds, i, getHeight()-12, this);
}
for (int i = 12; i < getHeight(); i += 12) {
buffer.drawImage(bounds, 0, i, this);
buffer.drawImage(bounds, getWidth()-12, i, this);
}
g.drawImage(this.img, 0, 0, getWidth(), getHeight(), null);
buffer.clearRect(12, 12, sizeX, sizeY);
}
public void play()
{
if (level == this.levels) gameend = true;
this.player.reset();
this.counter = 0;
this.appleCounter = 0;
long StartTime = System.currentTimeMillis();
player.update();
repaint();
/*do
{
Thread.yield();
}
while (System.currentTimeMillis() - StartTime < this.speed);*/
}
public void gameLoop()
{
while(true)
{
play();
try
{
Thread.sleep(150);
}
catch (InterruptedException ex)
{
}
if (death)
{
lives -= 1;
death = false; continue;
}
levelCompleted = false;
level+=1;
Levels.getLevel(level);
applesNumber = Levels.getApplesNumber();
}
}
public static int getApp()
{
return applesNumber;
}
public static int getSizeX()
{
return sizeX;
}
public static int getSizeY()
{
return sizeY;
}
public void setGameOver()
{
gameover = true;
}
#Override
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_ESCAPE) System.exit(0);
player.keyPressed(e);
}
#Override
public void keyReleased(KeyEvent e) {}
#Override
public void keyTyped(KeyEvent e) {}
}
and Game.class for JFrame
package snake;
import java.awt.Dimension;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import java.awt.BorderLayout;
#SuppressWarnings("serial")
public class Game extends JFrame {
//public SnakeTheGame start;
private ImageIcon icon;
StatBar statbar;
private MainGamePanel start;
public static final int WIDTH = 800;
public static final int HEIGHT = 700;
public static final int MIN_WIDTH = 450;
public static final int MIN_HEIGHT = 450;
public Game()
{
start = new MainGamePanel(new int[] { Settings.getLives(), Settings.getSpeed(), Settings.getLevels() });
statbar = new StatBar();
icon = new ImageIcon("img//icon.png");
setBounds(200, 200, WIDTH, HEIGHT);
setMinimumSize(new Dimension(MIN_WIDTH, MIN_HEIGHT));
setTitle("Snake The Game");
setIconImage(this.icon.getImage());
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
getContentPane().add(statbar, BorderLayout.SOUTH);
getContentPane().add(start, BorderLayout.CENTER);
// this.createBufferStrategy(2);
this.start.setVisible(true);
start.requestFocus();
}
public void start()
{
start.gameLoop();
}
}

JPanel is double-buffered by default. What you need to do is remove the loop in favour of a timer which does 60 FPS, calling play() and invoking one of the repaint methods.
Sample code
(Import from java.util. I did not use your names.)
private class AnimationTask extends TimerTask {
#Override
public void run() {
play();
animationPanel.repaint();
}
}
private Timer timer;
/**
* Creates new form AnimationDemoFrame
*/
public AnimationDemoFrame() {
timer = new Timer();
initComponents();
timer.schedule(new AnimationTask(), 150);
}
private void play() {
;
}