Develop Reference

Swing draws 3 JLabels instead of one

I don't really understand why this program draws three pawns instead of one and two of which seem to have a random(probably not so random) positions. enter image description here
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class GamePanel extends JPanel implements MouseListener {
static final int SCREEN_EDGE = 800;
static final int GAME_UNITS = 64;
static final int UNIT_SIZE = 100;
final int[] x = new int[GAME_UNITS];
final int[] y = new int[GAME_UNITS];
boolean running = false;
public GamePanel() {
this.setPreferredSize(new Dimension(SCREEN_EDGE, SCREEN_EDGE));
this.setFocusable(true);
this.addKeyListener(new MyKeyAdapter());
startGame();
int[] position = {0,0};
int[] position1 = {1, 0};
new Pawn(position,-1);
}
private void startGame() {
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
draw(g);
}
public void draw(Graphics g){
int counter = 1;
for (int y = 0; y < SCREEN_EDGE/UNIT_SIZE; y++) {
// 1 == "white" 2 == "black"
int color = (y % 2 == 0) ? 1 : 2;
for (int x = 0; x < SCREEN_EDGE/UNIT_SIZE; x++) {
g.setColor(color == 1 ? new Color(239,217, 181) : new Color(180, 136,98));
g.fillRect(x*UNIT_SIZE, y*UNIT_SIZE, UNIT_SIZE, UNIT_SIZE);
color = color == 1 ? 2 : 1;
}
}
for (int i = 0; i < Figure.figures.length; i++) {
JLabel figureSprite = new JLabel(Figure.figures[i].image, JLabel.CENTER);
figureSprite.setSize(90,90);
figureSprite.setLocation(Figure.figures[i].position[0] + 5,Figure.figures[i].position[1] + 5);
this.add(figureSprite);
}
}
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mousePressed(MouseEvent e) {
}
#Override
public void mouseReleased(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
}
#Override
public void mouseExited(MouseEvent e) {
}
public class MyKeyAdapter extends KeyAdapter {
#Override
public void keyPressed(KeyEvent e) {
}
}
}
import javax.swing.*;
public abstract class Figure{
protected int value;
protected ImageIcon image;
protected int[][] possibleMoves;
public int[] position;
// white = -1 black = 1
protected int whiteOrBlack;
protected static int figureCount = 1;
// int[figureCount][0 = x][1 = y][2 = color]
public static Figure[] figures = new Figure[figureCount];
public Figure(int value, int[] position, int[][] possibleMoves , int whiteOrBlack) {
this.value = value;
this.position = position;
this.possibleMoves = possibleMoves;
this.whiteOrBlack = whiteOrBlack;
Figure[] oldFigures = figures;
figures = new Figure[figureCount];
for (int i = 0; i < oldFigures.length; i++) {
figures[i] = oldFigures[i];
}
figures[figureCount - 1] = this;
figureCount++;
}
public abstract void move(int[] coordinates);
}
import javax.swing.*;
import java.awt.*;
import java.io.*;
public class Pawn extends Figure{
public Pawn(int[] position, int whiteOrBlack) {
super(1, position, new int[3][2], whiteOrBlack);
super.image = new ImageIcon(getClass().getClassLoader().getResource("graphics/" + (whiteOrBlack == -1 ? "whitePawn.png" : "blackPawn.png")));
Image newImage = super.image.getImage().getScaledInstance(90,90, Image.SCALE_AREA_AVERAGING);
super.image = new ImageIcon(newImage);
}
public void checkMoves(){
for (int i = 0; i < figures.length; i++) {
if((position[0] - 1) == figures[i].position[0] && (position[1] + this.whiteOrBlack) == figures[i].position[1] && figures[i].whiteOrBlack != this.whiteOrBlack) {
possibleMoves[0][0] = position[0] - 1;
possibleMoves[0][1] = position[1] + this.whiteOrBlack;
}else possibleMoves[0] = new int[2];
if((position[0]) != figures[i].position[0] && (position[1]) != figures[i].position[1]){
possibleMoves[1][0] = position[0];
possibleMoves[1][1] = position[1] + 1;
}else possibleMoves[1] = new int[2];
if((position[0] + 1) == figures[i].position[0] && (position[1] + this.whiteOrBlack) == figures[i].position[1] && figures[i].whiteOrBlack != this.whiteOrBlack) {
possibleMoves[2][0] = position[0] + 1;
possibleMoves[2][1] = position[1] + this.whiteOrBlack;
}else possibleMoves[2] = new int[2];
}
}
#Override
public void move(int[] coordinates) {
}
}
import javax.swing.*;
public class GameFrame extends JFrame {
public GameFrame(){
this.add(new GamePanel());
this.setTitle("Chess");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setResizable(false);
this.setVisible(true);
this.setLocationRelativeTo(null);
}
}
public class ChessGame {
public static void main(String[] args) {
new GameFrame();
}
}
I tried few thing like changing JLabel to BufferedImage but it would've generate other problems down the line like not being able to use MouseListener so i feel stuck. I would love to know why this code generates 3 textures too.

It looks like you are adding FigureSprites from within the drawComponent() method. The more often you draw the window, the more figures you have to draw.
Instead within drawComponent() just draw the current state but do not modify it. Adding figures has to come from somewhere else. For example, you could create the necessary pawns in the constructor. Or in extra methods that might get triggered based on user input.
In case you modify the GamePanel's state enough so that it should get painted freshly, just invoke repaint(). Swing will mark this component for repainting and decide on it's own when to run the paint() method, which in turn will run paintComponent().

Adding a JButton to a class extended by JPanel is not displaying a button

When I use normal JPanel initialized inside main instead of extended class. The button is added to a panel without problem and after launch is displayed in a center of a frame (default layout).
I would like to be able to add buttons inside an extended class. This problem occurs in Screen class aswell, where I need a Play Again button or Next Level button. The Screen is class extended by a JPanel too and JButtons are initialized inside the constructor aswell.
I'm not sure if the wrong part is in way of adding the components or in writing a code for a JPanel.
Here is the code:
Main:
public static void main(String[] args) {
// window - class JFrame
theFrame = new JFrame("Brick Breaker");
// game panel initialization
GamePanel gamePanel = new GamePanel(1);
theFrame.getContentPane().add(gamePanel);
// base settings
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
theFrame.setLocationRelativeTo(null);
theFrame.setResizable(false);
theFrame.setSize(WIDTH, HEIGHT);
theFrame.setVisible(true);
}
GamePanel Class:
public class GamePanel extends JPanel {
// Fields
boolean running;
boolean clicked = false;
private int rows = 8, colms = 11, N = rows * colms, level; // numbers of rows and columns
private int colmsC, rowsC;
private BufferedImage image;
private Graphics2D g;
private MyMouseMotionListener theMouseListener;
private MouseListener mouseListener;
private int counter = 0;
// entities
Ball theBall;
Paddle thePaddle;
Bricle[] theBricks;
Screen finalScreen;
public GamePanel(int level) {
// buttons
JButton pause = new JButton(" P ");
add(pause);
this.level = level;
init(level);
}
public void init(int level) {
// level logic
this.rowsC = level + rows;
this.colmsC = level + colms;
int count = rowsC * colmsC;
thePaddle = new Paddle();
theBall = new Ball();
theBall.setY(thePaddle.YPOS - thePaddle.getHeight() + 2);
theBall.setX(thePaddle.getX() + thePaddle.getWidth() / 2 - 5);
theBricks = new Bricle[count];
theMouseListener = new MyMouseMotionListener();
addMouseMotionListener(theMouseListener);
mouseListener = new MyMouseListener();
addMouseListener(mouseListener);
// make a canvas
image = new BufferedImage(BBMain.WIDTH, BBMain.HEIGHT, BufferedImage.TYPE_INT_RGB);
g = (Graphics2D) image.getGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// specific Bricks initialized
int k = 0;
for (int row = 0; row < rowsC; row++) {
for (int col = 0; col < colmsC; col++) {
theBricks[k] = new Bricle(row, col);
k++;
}
}
running = true;
}
public void playGame() {
while (running) {
//update
if (clicked) {
update();
}
// draw
draw();
// display
repaint();
// sleep
try {
Thread.sleep(20);
} catch (Exception e) {
e.printStackTrace();
}
}
}
// update loop ( like playGame )
public void update() {
// ball moving
checkCollisions();
theBall.update();
}
public void draw() {
// background
g.setColor(Color.WHITE);
g.fillRect(0,0, BBMain.WIDTH, BBMain.HEIGHT-20);
// the bricks
int k = 0;
for (int row = 0; row < rowsC; row++) {
for (int col = 0; col < colmsC; col++) {
theBricks[k].draw(g, row, col);
k++;
}
}
// the ball and the paddle
theBall.draw(g);
thePaddle.draw(g);
// counter
String countString = new Integer(this.counter).toString();
g.drawString(countString, 20, 20);
// WIN / LOOSE SCREEN
if (this.counter == this.N * 20) {
win();
}
if (theBall.getRect().getY() + theBall.getRect().getHeight() >= BBMain.HEIGHT) {
loose();
}
}
public void paintComponent(Graphics g) {
// retype
Graphics2D g2 = (Graphics2D) g;
// draw image
g2.drawImage(image, 0, 0, BBMain.WIDTH, BBMain.HEIGHT, null);
// dispose
g2.dispose();
}
public void pause() {
this.running = false;
finalScreen = new Screen(this.level, counter);
finalScreen.draw(g,"GAME PAUSED");
}
public void win() {
this.running = false;
finalScreen = new Screen(this.level, counter);
finalScreen.draw(g,"YOU WIN");
}
public void loose () {
this.running = false;
finalScreen = new Screen(this.level, counter);
finalScreen.draw(g,"YOU LOOSE");
}
public void addScore() {
this.counter += 20;
theBall.setDY(theBall.getDY() - 0.001);
}
// Mouse Listeners
private class MyMouseListener implements MouseListener {
#Override
public void mouseClicked(MouseEvent e) {
clicked = true;
}
#Override
public void mousePressed(MouseEvent e) {
}
#Override
public void mouseReleased(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
}
#Override
public void mouseExited(MouseEvent e) {
}
}
private class MyMouseMotionListener implements MouseMotionListener {
#Override
public void mouseDragged(MouseEvent e) {
}
#Override
public void mouseMoved(MouseEvent e) {
if (clicked)
thePaddle.mouseMoved(e.getX());
}
}
}

Active rendering on a JPanel with ImageIcon tiles? #Java

So I'm trying to write a tile-grid based game and came up with a quite unusual solution. I filled a 2D JPanel Array with JLabels with an ImageIcon as tile. Everything works so far but I did not find any way to render this activly.
I've tryied some methods for active rendering I found on the Internet, but they did not work on my idea. Do you have some ideas how to realize this without rewrite everything to Canvas or something similar?
Here's my code:
Window
public class Win extends JFrame {
private static final long serialVersionUID = 1L;
private BufferStrategy bs;
public Win(int x, int y) {
this.setSize(x, y);
this.setVisible(true);
this.setResizable(false);
this.setIgnoreRepaint(true);
this.createBufferStrategy(2);
setBs(getBufferStrategy());
}
public BufferStrategy getBs() {
return bs;
}
public void setBs(BufferStrategy bs) {
this.bs = bs;
}
}
"Draw"
public class Field extends JPanel {
private static final long serialVersionUID = 5257799495742189076L;
private int x = 0;
private int y = 0;
private JPanel backPanel[][] = new JPanel[19][19];
private BufferedImage images[] = new BufferedImage[100];
private JLabel image[][] = new JLabel[19][19];
public Field() {
this.setLayout(new GridLayout(20, 20));
this.setIgnoreRepaint(true);
}
// Creates Panel Grid & Draws floor
public void setPanels() {
for (int h = 0; h < 19; h++) {
for (int w = 0; w < 19; w++) {
backPanel[h][w] = new JPanel();
backPanel[h][w].setLayout(new GridLayout(1, 1));
image[h][w] = new JLabel(new ImageIcon(images[0]));
backPanel[h][w].add(image[h][w]);
this.add(backPanel[h][w]);
}
}
}
// Loads the Textures
public void getTextures() throws IOException {
for (int i = 0; i < 1; i++) {
images[i] = ImageIO.read(new File("texture.png"));
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(images[1], 0, 0, null);
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
}
Game Loop
public class GameLoop implements Runnable {
private boolean runFlag = true;
#Override
public void run() {
Field field = new Field();
Win window = new Win(640, 640);
window.add(field);
try {
field.getTextures();
} catch (IOException e) {
e.printStackTrace();
}
while (runFlag) {
try {
field.setPanels();
window.getBs().show();
Thread.sleep(20);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void stop() {
runFlag = false;
}
}

Some alternatives:
Shuffle the components and do removeAll(), add(), and validate() as shown here.
Shuffle the contents and do setIcon(), as shown here.
In either case,
Use javax.swing.Timer to pace the animation, as shown here and here.
Consider TexturePaint to fill the icons, as shown here.

How to access a JButton from another class

I have two classes 'UserInterface' and a 'GameEngine' I have declared a JButton component in the UserInterface and I am trying to use one of the variables i.e use the variable 'button1' from 'UserInterface' in the 'horizontalWin' method from the class 'GameEngine'.
I got this error instead "cannot find symbol - variable button1"
Userinterface:
public class UserInterface implements ActionListener
{
private GameEngine game;
private JFrame frame;
JButton button1 = new JButton("");
JButton button2 = new JButton("");
JButton button3 = new JButton("");
JButton button4 = new JButton("");
JButton button5 = new JButton("");
JButton button6 = new JButton("");
JButton button7 = new JButton("");
JButton button8 = new JButton("");
JButton button9 = new JButton("");
/**
* Create a user interface.
* #param engine The game's engine.
*/
public UserInterface(GameEngine engine)
{
game = engine;
makeFrame();
}
//some methods
}
GameEngine:
public class GameEngine {
private String buttonName;
boolean winner = false;
byte count;
public GameEngine()
{
count = 0;
}
public void horizontalWin()
{
if(button1.getText()==button2.getText() && button2.getText()==button3.getText() && button1.getText()!="" )
{
winner=true;
playAgain(buttonName);
}
// Horizontal win row 2
else if(button4.getText()==button5.getText() && button5.getText()==button6.getText() && button4.getText()!="" )
{
winner=true;
playAgain(buttonName);
}
// horizontal win row 3
else if(button7.getText()==button8.getText() && button8.getText()==button9.getText() && button7.getText()!="")
{
winner=true;
playAgain(buttonName);
}
}

I think that you don't really want to do this, that you don't want your game engine trying to obtain variables from the view. Rather why not have your view notify the engine or "model" (usually through something called a "control", when a button has been pressed. The engine then can keep track of what has been pressed and change its state accordingly. The View can then change in response to changes in the engine's state.
For example:
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
import javax.swing.event.SwingPropertyChangeSupport;
public class TicTacToe {
private static void createAndShowGui() {
View mainPanel = new View();
JFrame frame = new JFrame("TicTacToe");
frame.setDefaultCloseOperation(JFrame.EXIT_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();
}
});
}
}
#SuppressWarnings("serial")
class View extends JPanel {
private static final int GAP = 2;
private static final Font BTN_FONT = new Font(Font.SANS_SERIF, Font.BOLD, 42);
private JButton[][] gameGrid = new JButton[Engine.ROWS][Engine.ROWS];
private Engine engine = new Engine();
public View() {
engine.addPropertyChangeListener(Engine.GAME_OVER, new GameOverListener());
JPanel gameGridPanel = new JPanel(new GridLayout(Engine.ROWS, Engine.ROWS, GAP, GAP));
for (int i = 0; i < gameGrid.length; i++) {
for (int j = 0; j < gameGrid[i].length; j++) {
gameGrid[i][j] = createGameGridButton(i, j);
gameGridPanel.add(gameGrid[i][j]);
}
}
JButton resetBtn = new JButton(new ResetAction("Reset", KeyEvent.VK_R));
JPanel northPanel = new JPanel();
northPanel.add(resetBtn);
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
setLayout(new BorderLayout(GAP, GAP));
add(gameGridPanel, BorderLayout.CENTER);
add(northPanel, BorderLayout.NORTH);
}
private JButton createGameGridButton(int i, int j) {
JButton button = new JButton();
button.setName(String.format("%d,%d", i, j));
button.setText(XO.BLANK.getText());
button.setFont(BTN_FONT);
button.addActionListener(new GridButtonListener(i, j));
return button;
}
private class GridButtonListener implements ActionListener {
private int i;
private int j;
public GridButtonListener(int i, int j) {
this.i = i;
this.j = j;
}
#Override
public void actionPerformed(ActionEvent e) {
if (engine.isGameOver()) {
return;
}
AbstractButton source = (AbstractButton) e.getSource();
String text = source.getText();
if (text.trim().isEmpty()) {
source.setText(engine.getTurn().getText());
engine.setXO(i, j);
}
}
}
private class ResetAction extends AbstractAction {
public ResetAction(String text, int mnemonic) {
super(text);
putValue(MNEMONIC_KEY, mnemonic);
}
public void actionPerformed(ActionEvent e) {
engine.reset();
for (JButton[] row : gameGrid) {
for (JButton button : row) {
button.setText(XO.BLANK.getText());
}
}
};
}
private class GameOverListener implements PropertyChangeListener {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getNewValue() == Boolean.TRUE) {
JOptionPane.showMessageDialog(View.this, engine.getTurn()
.getText() + " is a winner!", "We Have a Winner!",
JOptionPane.INFORMATION_MESSAGE);
}
}
}
}
class Engine {
public static final int ROWS = 3;
public static final String GAME_OVER = "game over";
private XO[][] grid = new XO[ROWS][ROWS];
private XO turn = XO.X;
private boolean gameOver = false;
private SwingPropertyChangeSupport pcSupport = new SwingPropertyChangeSupport(
this);
public Engine() {
reset();
}
public XO getTurn() {
return turn;
}
public boolean isGameOver() {
return gameOver;
}
public void setXO(int row, int col) {
grid[row][col] = turn;
checkForWin(row, col);
turn = (turn == XO.X) ? XO.O : XO.X;
}
public void reset() {
for (int r = 0; r < grid.length; r++) {
for (int c = 0; c < grid[r].length; c++) {
grid[r][c] = XO.BLANK;
}
}
turn = XO.X;
gameOver = false;
}
public void checkForWin(int i, int j) {
boolean win = true;
for (int col = 0; col < grid.length; col++) {
if (grid[col][j] != turn) {
win = false;
}
}
if (!win) {
win = true;
for (int row = 0; row < grid[i].length; row++) {
if (grid[i][row] != turn) {
win = false;
}
}
}
if (!win && i == j) {
win = true;
for (int k = 0; k < grid.length; k++) {
if (grid[k][k] != turn) {
win = false;
}
}
}
if (!win && i + j == 2) {
win = true;
for (int k = 0; k < grid.length; k++) {
if (grid[k][2 - k] != turn) {
win = false;
}
}
}
if (win) {
setGameOver(true);
}
}
private void setGameOver(boolean gameOver) {
boolean oldValue = this.gameOver;
boolean newValue = gameOver;
this.gameOver = gameOver;
pcSupport.firePropertyChange(GAME_OVER, oldValue, newValue);
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(listener);
}
public void removePropertyChangeListener(PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(listener);
}
public void addPropertyChangeListener(String name,
PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(name, listener);
}
public void removePropertyChangeListener(String name,
PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(name, listener);
}
}
enum XO {
X("X"), O("O"), BLANK(" ");
private String text;
private XO(String text) {
this.text = text;
}
public String getText() {
return text;
}
}
My view's ActionListener (here an AbstractAction) notifies the Engine that a certain button has been pushed. The Engine keeps track of which button has been pushed, and when a winner has been determined, sets a gameOver field thereby notifying all listeners that the game is over.

Java swing repainting while computing: animating sorting algorithm

http://www.youtube.com/watch?v=M0cNsmjK33E
I want to develop something similar to the link above using Java Swing. I have the sorting method and did while repaint but when I triggered the sorting, instead of showing the bars slowly sorting itself, it freezes and then unfreezes when the array has been fully sorted.
How do I fix this?
Edit: sorry forgot about the codes. its a very simple gui. and another class for sorting which sorts the whole array
public class SortGUI {
JFrame frame;
int frameWidth = 1000, frameHeight = 1000;
int panelWidth, panelHeight;
DrawPanel panel;
JPanel panel2;
JScrollPane scroll;
JViewport view;
static int[] S = new int[50000];
public static void main(String[] args) throws InterruptedException {
SortGUI app = new SortGUI();
initializeArray();
app.go();
}
public static void initializeArray()
{
for (int i = 0; i < S.length; i++) {
S[i] = (int) (Math.random() * 16581375);
}
}
public void go() throws InterruptedException {
//Frame
frame = new JFrame();
frame.setSize(frameWidth, frameHeight);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//panel
panel = new DrawPanel();
scroll = new JScrollPane(panel,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//Layout
frame.add(scroll);
frame.addKeyListener(new keyListener());
while(true)
{
panel.repaint();
}
}
public class DrawPanel extends JPanel
{
public DrawPanel()
{
this.setPreferredSize(new Dimension(50000,930));
}
public void paintComponent(Graphics g)
{
g.setColor(Color.WHITE);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
for(int i = 0; i < S.length; i++)
{
int red = S[i] / 65025;
int green = (S[i] > 65025)? S[i] % 65025 : 0;
int blue = green;
blue %= 255;
green /= 255;
g.setColor(new Color(red,green,blue));
g.fillRect(i, 900 - (S[i] / 18500), 1, S[i] / 18500);
}
}
}
public class keyListener implements KeyListener{
public void keyTyped(KeyEvent ke) {
}
public void keyPressed(KeyEvent ke) {
if(ke.getKeyChar() == '1')
{
sorter.bubbleSort(S);
}
}
public void keyReleased(KeyEvent ke) {
}
}
}

Note: I started writing this before the question was deleted
Most likely your using some looping mechanism and praying that each iteration, the ui with be updated. That's a wrong assumption. The UI will not be update until the loop is finished. What you are doing is what we refer to as blocking the Event Dispatch Thread(EDT)
See How to use a Swing Timer. Make "iterative" updates in the ActionListener call back. For instance, if you want to animate a sorting algorithm, you need to determine what needs to be updated per "iteration" of the timer callback. Then each iteration repaint the ui.
So your Timer timer could look something like
Timer timer = new Timer(40, new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
if (sortingIsDone()) {
((Timer)e.getSource()).stop();
} else {
sortOnlyOneItem();
}
repaint();
}
});
Your sortOnlyOneItem method should only, well, perform a sort for just one item. And have some sort of flag to check if the sorting is done, then stop the timer.
Other notes:
You should be calling super.paintComponent in the paintComponent method, if you aren't going to paint the background yourself. Generally I always do though.
Here's a complete example. I'm glad you figured it out on your own. I was working on this example before I saw that you got it.
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;
import java.util.Collections;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class SelectionSortAnimate extends JPanel {
private static final int NUM_OF_ITEMS = 20;
private static final int DIM_W = 400;
private static final int DIM_H = 400;
private static final int HORIZON = 350;
private static final int VERT_INC = 15;
private static final int HOR_INC = DIM_W / NUM_OF_ITEMS;
private JButton startButton;
private Timer timer = null;
private JButton resetButton;
Integer[] list;
int currentIndex = NUM_OF_ITEMS - 1;
public SelectionSortAnimate() {
list = initList();
timer = new Timer(200, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (isSortingDone()) {
((Timer) e.getSource()).stop();
startButton.setEnabled(false);
} else {
sortOnlyOneItem();
}
repaint();
}
});
startButton = new JButton("Start");
startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
timer.start();
}
});
resetButton = new JButton("Reset");
resetButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
list = initList();
currentIndex = NUM_OF_ITEMS - 1;
repaint();
startButton.setEnabled(true);
}
});
add(startButton);
add(resetButton);
}
public boolean isSortingDone() {
return currentIndex == 0;
}
public Integer[] initList() {
Integer[] nums = new Integer[NUM_OF_ITEMS];
for (int i = 1; i <= nums.length; i++) {
nums[i - 1] = i;
}
Collections.shuffle(Arrays.asList(nums));
return nums;
}
public void drawItem(Graphics g, int item, int index) {
int height = item * VERT_INC;
int y = HORIZON - height;
int x = index * HOR_INC;
g.fillRect(x, y, HOR_INC, height);
}
public void sortOnlyOneItem() {
int currentMax = list[0];
int currentMaxIndex = 0;
for (int j = 1; j <= currentIndex; j++) {
if (currentMax < list[j]) {
currentMax = list[j];
currentMaxIndex = j;
}
}
if (currentMaxIndex != currentIndex) {
list[currentMaxIndex] = list[currentIndex];
list[currentIndex] = currentMax;
}
currentIndex--;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (int i = 0; i < list.length; i++) {
drawItem(g, list[i], i);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(DIM_W, DIM_H);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Sort");
frame.add(new SelectionSortAnimate());
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}