Develop Reference

Why while changing the content in the text box is not changing the size of the scroll bars?

English is not my native language excuse me if there is grammar mistakes.
This is a program for a text editor.
The Rule class is used as row header for ScrollableTextArea The ScrollableTextArea extends JTextArea and implements Scrollable it also implementsMouseMotionListener so user can scroll(move the knob) by clicking on the track.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.Scrollable;
import javax.swing.SwingConstants;
/**
*Classes required
*Rule.java
*ScrollableTextArea
* #author Dev Parzival
*/
public class Note extends JPanel{
static int NUMBER_PANEL_WIDTH=50;
private ScrollableTextArea scrollableTextArea;
private Rule rowView;
private JScrollPane scroll;
public Note(Dimension size,File file) {
rowView=new Rule(SwingConstants.VERTICAL,getIncrement());
scrollableTextArea=new ScrollableTextArea(rowView.getIncrement());
boolean flag=fetchData(scrollableTextArea, file);
rowView.setPreferredHeight(scrollableTextArea.getHeight());
if(!flag)
return;
scroll=new JScrollPane(scrollableTextArea);
scroll.setPreferredSize(size);
scroll.setRowHeaderView(rowView);
scroll.setViewportBorder(BorderFactory.createLineBorder(Color.black));
add(scroll);
setSize(size);
setVisible(true);
}
private boolean fetchData(JTextArea text,File file){
FileReader scan;
BufferedReader br;
try{
scan=new FileReader(file);
String msg="";
br=new BufferedReader(scan);
try{
while(true){
String data=br.readLine();
if(data==null)
break;
msg+=data+"\n";
}
text.setText(msg);
}
catch(IOException ex){
JOptionPane.showMessageDialog(this,"Error Occured while reading "+file.getAbsolutePath()+".","Error",JOptionPane.INFORMATION_MESSAGE);
}
}
catch(FileNotFoundException ex){
JOptionPane.showMessageDialog(this,"Cannot found this path : "+file.getAbsoluteFile(),"Error",JOptionPane.INFORMATION_MESSAGE);
return false;
}
return true;
}
/*Here the unit is the height of the text inside the textArea*/
public int getIncrement(){
JTextArea ta=new JTextArea();
return ta.getFontMetrics(ta.getFont()).getHeight();
}
public static void createAndShowGUI(){
JFrame frame = new JFrame("ScrollDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
//Create and set up the content pane.
JComponent newContentPane = new Note(frame.getSize(),new File("C:\\Users\\DevParzival\\Documents\\pro.txt"));
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
//frame.pack();
frame.setVisible(true);
}
public static void main(String $[]){
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
}
class Rule extends JComponent {
public static int INCH;
public static final int HORIZONTAL = 0;
public static final int VERTICAL = 1;
public static final int SIZE = 35;
public int orientation;
private int increment;
private int units;
public Rule(int o,int height) {
orientation = o;
INCH=height;
setIncrementAndUnits();
}
private void setIncrementAndUnits() {
increment = units=INCH;
}
public int getIncrement() {
return increment;
}
public void setPreferredHeight(int ph) {
setPreferredSize(new Dimension(SIZE, ph));
}
public void setPreferredWidth(int pw) {
setPreferredSize(new Dimension(pw, SIZE));
}
protected void paintComponent(Graphics g) {
Rectangle drawHere = g.getClipBounds();
System.out.println(drawHere);
// Fill clipping area with dirty brown/orange.
g.setColor(new Color(230, 163, 4));
g.fillRect(drawHere.x, drawHere.y, drawHere.width, drawHere.height);
// Do the ruler labels in a small font that's black.
g.setFont(new Font("SansSerif", Font.PLAIN, 10));
g.setColor(Color.black);
// Some vars we need.
int end = 0;
int start = 0;
int tickLength = 0;
String text = null;
// Use clipping bounds to calculate first and last tick locations.
if (orientation == HORIZONTAL) {
start = (drawHere.x / increment) * increment;
end = (((drawHere.x + drawHere.width) / increment) + 1)
* increment;
} else {
start = (drawHere.y / increment) * increment;
end = (((drawHere.y + drawHere.height) / increment) + 1)
* increment;
}
// Make a special case of 0 to display the number
// within the rule and draw a units label.
// if (start == 0) {
// text = Integer.toString(0);
// tickLength = 10;
// if (orientation == HORIZONTAL) {
// g.drawLine(0, SIZE-1, 0, SIZE-tickLength-1);
// g.drawString(text, 2, 21);
// } else {
// g.drawLine(SIZE-1, 0, SIZE-tickLength-1, 0);
// g.drawString(text, 9, 10);
// }
// text = null;
// start = increment;
// }
// ticks and labels
for (int i = start; i < end; i += increment) {
if (i % units == 0) {
tickLength = 10;
text = Integer.toString(i/units);
} else {
tickLength = 7;
text = null;
}
if (tickLength != 0) {
if (orientation == HORIZONTAL) {
g.drawLine(i, SIZE-1, i, SIZE-tickLength-1);
if (text != null)
g.drawString(text, i-3, 21);
} else {
g.drawLine(SIZE-1, i, SIZE-tickLength-1, i);
if (text != null)
g.drawString(text, 9, i+3+increment/2);
}
}
}
}
}
class ScrollableTextArea extends JTextArea implements Scrollable,MouseMotionListener {
private int maxUnitIncrement = 1;
public ScrollableTextArea(int m) {
maxUnitIncrement = m;
//Let the user scroll by dragging to outside the window.
setAutoscrolls(true); //enable synthetic drag events
addMouseMotionListener(this); //handle mouse drags
}
//Methods required by the MouseMotionListener interface:
public void mouseMoved(MouseEvent e) { }
public void mouseDragged(MouseEvent e) {
//The user is dragging us, so scroll!
Rectangle r = new Rectangle(e.getX(), e.getY(), 1, 1);
scrollRectToVisible(r);
}
public Dimension getPreferredSize() {
return new Dimension(500,500);
}
public Dimension getPreferredScrollableViewportSize() {
return getPreferredSize();
}
public int getScrollableUnitIncrement(Rectangle visibleRect,
int orientation,
int direction) {
//Get the current position.
int currentPosition = 0;
if (orientation == SwingConstants.HORIZONTAL) {
currentPosition = visibleRect.x;
} else {
currentPosition = visibleRect.y;
}
//Return the number of pixels between currentPosition
//and the nearest tick mark in the indicated direction.
if (direction < 0) {
int newPosition = currentPosition -
(currentPosition / maxUnitIncrement)
* maxUnitIncrement;
return (newPosition == 0) ? maxUnitIncrement : newPosition;
} else {
return ((currentPosition / maxUnitIncrement) + 1)
* maxUnitIncrement
- currentPosition;
}
}
public int getScrollableBlockIncrement(Rectangle visibleRect,
int orientation,
int direction) {
if (orientation == SwingConstants.HORIZONTAL) {
return visibleRect.width - maxUnitIncrement;
} else {
return visibleRect.height - maxUnitIncrement;
}
}
public boolean getScrollableTracksViewportWidth() {
return false;
}
public boolean getScrollableTracksViewportHeight() {
return false;
}
public void setMaxUnitIncrement(int pixels) {
maxUnitIncrement = pixels;
}
}
From the above pic it is visible that changing the content of the
textArea is not changing the size of the scroll bars.
How could we make the scroll bar to adjust as the content inside the scrollableTextArea changes?
How to fix the bug?
Thanks in advance.

How do I pass an object from another class into the paintComponent method?

My assignment is to create the game "FloodIt." You can play the game here if you need to understand it, but I don't think it's really necessary: http://unixpapa.com/floodit/
I have finished the actual game part of it, but now I need to make a graphical interface for it. I have three classes:
Board.java, which makes the board with random int values and contains several other methods to make the game work:
import java.awt.Color;
import java.util.Random;
/**The board class for the Flood-It game. This class implements a NxN board filled with numColors colors.
* The class implements several methods to allow the playing of the game.
*/
class Board {
//you will probably need to create some field variables
private int size;
private int numColors;
private int[][] board;
private int numOfMoves;
/**Constructs a new sizeXsize board filled where each element on the board is a random number between 0
* and numColors. Also initializes the number of moves to zero.
* #param size -- the size of the board
* #param numColors -- the number of possible entries on the board
*/
public Board(int size,int numColors) {
//TODO finish this constructor
this.size = size;
this.numColors = numColors;
numOfMoves = 0;
board = new int[size][size];
Random rand = new Random();
int randomNum = 0;
for (int count = 0; count < size; count++) {
for (int counter = 0; counter < size; counter++) {
randomNum = rand.nextInt(this.numColors);
board[count][counter] = randomNum;
}
}
}
/**Updates the board to fill (from the top left corner) with a specified color.
* Filling stops when any other color is hit besides the one in the top left corner.
* Play the game at http://www.lemoda.net/javascript/flood-it/ or http://unixpapa.com/floodit/?sz=14&nc=4
* to get a better understanding of what this method should do.
* You will probably also want to take a look at the algorithm described
* at http://en.wikipedia.org/wiki/Flood_fill which describes what this method should do.
* I recommend the Stack-based recursive implementation. It is a recursive algorithm for
* flooding the board. It is one of the easier ones to implement.
* You are free to have this method call other methods. I would recommend creating a private method that
* this method calls and have that private method be the recursive method.
* A recursive method is one that calls itself.
* #param color -- the new color to flood the board with.
*/
public void move(int replacementColor) {
int targetColor = board[0][0];
recursiveMove(0,0,targetColor,replacementColor);
numOfMoves++;
}
private void recursiveMove(int xCoord, int yCoord, int targetColor, int replacementColor) {
if (targetColor == replacementColor) {
return;
}
if (board[xCoord][yCoord] != targetColor) {
return;
}
board[xCoord][yCoord] = replacementColor;
if (yCoord != size-1) {
recursiveMove(xCoord,yCoord+1,targetColor,replacementColor);
}
if (yCoord != 0) {
recursiveMove(xCoord,yCoord-1,targetColor,replacementColor);
}
if (xCoord != 0) {
recursiveMove(xCoord-1,yCoord,targetColor,replacementColor);
}
if (xCoord != size-1) {
recursiveMove(xCoord+1,yCoord,targetColor,replacementColor);
}
}
/**returns true if the board is not completely filled with a single color.
* Otherwise it returns false.
* #return true if board is all one color
*/
public boolean finished() {
//TODO finish this method
for (int count = 0; count < size; count++) {
for (int counter = 0; counter < size; counter++) {
if (board[count][counter] != board[0][0]) {
return false;
}
}
}
return true;
}
/**returns how many times the move() method has been called.
* #return the number of times the move() method has been called.
*/
public int numMoves() {
//TODO finish this method
return numOfMoves;
}
/**Returns a string representation of the board. Use tabs between elements of the board.
* And have every row of the board be separated by a newline character.
* Example:
* "1\t0\t3\t\n2\t0\t2\t\n1\t0\t1\t\n"
* #return a String representation of the board
*/
public String toString() {
//TODO finish this method
String boardString = "";
for (int count = 0; count < board.length; count++) {
for (int counter = 0; counter < board.length; counter++) {
boardString += board[count][counter];
boardString += "\t";
}
boardString += "\n";
}
return boardString;
}
}
FloodIt.java, which contains the JFrame lines in order to load the graphical interface, as well as code to actually run the game (it's not entirely finished, as I got stuck):
import java.util.Scanner;
import javax.swing.JFrame;
/**This class is the main method for the Flood-It game as found on many web sites
* ( such as http://www.lemoda.net/javascript/flood-it/ or
http://unixpapa.com/floodit/?sz=14&nc=4 ).
* It prompts the user for the size of the board
* and the number of colors. The user is prompted for the next color until the board is flooded.
* After the game is over it prints how many turns the user took and then asks if they want to play again.
*/
class FloodIt {
private static final int FRAMESIZE = 1000;
public static void main(String args[]) {
JFrame frame = new JFrame();
frame.setSize(FRAMESIZE,FRAMESIZE);
frame.setTitle("Brennan's Game");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GraphicalBoard component = new GraphicalBoard();
frame.add(component);
frame.setVisible(true);
String again="";
int size = 20;
int numColors = 7;
do {
Board board=new Board(size,numColors);
while(!board.finished()) {
//I will change the print statements below into graphical input boxes later
System.out.print("****************\n"+board+"\n****************\n");
System.out.print("What color do you choose? ");
int color=Integer.parseInt(scan.nextLine());
board.move(color);
}
System.out.println("Nice job, you finished in "+board.numMoves());
System.out.print("Would you like to play again (Y/N)? ");
again=scan.nextLine();
} while (again.equalsIgnoreCase("Y"));
scan.close();
}
}
And GraphicalBoard.java, which is supposed to take the values of the 2d array from Board.java and display the board in a graphical interface. Each number that could be in the 2d array corresponds with a color in the Colors array:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JComponent;
public class GraphicalBoard extends JComponent {
private int xSize = 50;
private int ySize = 50;
public void paintComponent(Graphics g, int size, Board board) {
String colors[] = {"BLUE","GREEN","YELLOW","RED","BLACK","ORANGE","PINK"};
Graphics2D g2 = (Graphics2D) g;
int xCoord = 0;
int yCoord = 0;
int colorNum = 0;
String colorOfSquare = "";
for (int count = 0; count < size; count++) {
for (int counter = 0; counter < size; counter++) {
colorNum = board[count][counter];
colorOfSquare = colors[colorNum];
g2.setColor(Color.colorOfSquare);
Rectangle square = new Rectangle(xCoord,yCoord,xSize,ySize);
xCoord += 50;
}
yCoord += 50;
}
}
}
Two problems:
In GraphicalBoard.java, on the line "colorNum = board[count][counter];", I am getting the error: "The type of expression must be an array type but it resolved to Board."
I seem to be having a problem bring over the already initialized board from the Board.java class into the GraphicalBoard.java class.
In GraphicalBoard.java, on the line "g2.setColor(Color.colorOfSquare);", I am getting the error: "colorOfSquare cannot be resolved or it not a field."
I know the problem, it is supposed to be something like "g2.setColor(Color.BLACK);", but I am going to have the user input the color, so it kind of needs to be a variable and I was hoping to have something cleaner than just an if statement for every color.
Any suggestions? Thanks!

Your Board class contains a member variable int[][] board, but its scope is private. When you call the following:
colorNum = board[count][counter];
This is wrong because the board variable here is an object of Board class. It itself is not the two day array, but it encapsulates int[][] board inside it. So you need to provide a getter method in Board to expose its board member variable like this:
public int[][] getBoard() {
return board;
}
Then in the paintComponent method you can access it as: board.getBoard()[count][counter].
You already seem to have a user inputted color in the colorOfSquare variable. But Graphics2D's setColor method would only accept a variable of type java.awt.Color. Since you have the String representation of the color, you can get its corresponding java.awt.Color value using reflection as mentioned here. The following should work for you:
Color color;
try {
Field field = Color.class.getField(colorOfSquare);
color = (Color) field.get(null);
} catch (Exception e) {
color = null; // Not defined
}

Two answers:
paintComponent ONLY receives a Graphics object. See this link for a short tutorial. If you need to access other objects in this method, make them variables of GraphicalBoard and pass them om during construction.
1.5 You need to access the Board's board, as this is what you are using. So add a getBoard(int i, int j) in class Board. Something like the following (I also added a getSize() method) :
public int getBoard(int i, int j) {
return board[i][j] ;
}
public int getSize() {
return size;
}
Your color colorOfSquare is already defined as a color. The error arises because the Color class doesn't have such a constant. You should just pass the color directly.
Try this:
public class GraphicalBoard extends JComponent {
private int xSize = 50;
private int ySize = 50;
private Board board;
private int size;
public GraphicalBoard() {
}
public void setBoard(Board board){
this.board = board;
}
public void paintComponent(Graphics g) {
super.paintComponent();
if(board == null) {
throw new RuntimeException("Board not set") ;
}
String colors[] = {"BLUE","GREEN","YELLOW","RED","BLACK","ORANGE","PINK"};
Graphics2D g2 = (Graphics2D) g;
int xCoord = 0;
int yCoord = 0;
int colorNum = 0;
int size = board.getSize() ;
String colorOfSquare = "";
for (int count = 0; count < size; count++) {
for (int counter = 0; counter < size; counter++) {
colorNum = board.getBoard(count, counter) ;
colorOfSquare = colors[colorNum];
g2.setColor(colorOfSquare);
Rectangle square = new Rectangle(xCoord,yCoord,xSize,ySize);
xCoord += 50;
}
yCoord += 50;
}
}

In very general terms,
your view, here the drawing JPanel, should contain a reference to the model object via a has-a or "composition" structure
The view should be notified of changes in the model, often via event listeners such as a PropertyChangeListener
The view then extracts the key information and uses that to help decide what to draw. So, if it has a reference to the current Board object, it can make getter method calls from within the paintComponent method.
Other issues in your code:
Make sure to call the super's paintComponent within your override, else you will not clean up "dirty" pixels
Don't mix linear code -- a Scanner based on System.in with GUI code. Make it all one or the other.
For example, in the code below, I use a model class, the class that holds the int[][] board variable and here called BoardModel, and I give it a SwingPropertyChangeSupport object.
class BoardModel {
// .....
private SwingPropertyChangeSupport support = new SwingPropertyChangeSupport(this);
This object will accept listeners, and will allow me to notify listeners of changes to the model.
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
support.addPropertyChangeListener(propertyName, listener);
}
Then when the model changes, I notify all listeners by calling the support object's firePropertyChange(...) method:
public void selectSquare(int x, int y) {
int replacementValue = board[y][x];
int targetValue = board[0][0];
if (targetValue == replacementValue) {
return;
} else {
recursiveMove(0, 0, targetValue, replacementValue);
numOfMoves++;
support.firePropertyChange(BOARD, null, board); // ***** here
setWin(checkForWin());
}
}
Then in the control, I can add listeners that notify the view of changes:
model.addPropertyChangeListener(BoardModel.BOARD, new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent e) {
view.repaint();
String moveCount = "" + model.getNumOfMoves();
controlPanel.setMoveCountFieldText(moveCount);
}
});
model.addPropertyChangeListener(BoardModel.WIN, new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ((boolean) evt.getNewValue()) {
String message = "Move count: " + model.getNumOfMoves();
String title = "Game Over";
int messageType = JOptionPane.PLAIN_MESSAGE;
JOptionPane.showMessageDialog(view, message, title, messageType);
}
}
});
A working example could look like this:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.event.SwingPropertyChangeSupport;
public class BoardFun {
private static final int NUM_COLORS = 6;
private static final int SIZE = 20;
#SuppressWarnings("serial")
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
int size = SIZE;
int numColors = NUM_COLORS;
final BoardModel model = new BoardModel(size , numColors );
final BoardPanel view = new BoardPanel();
final ControlPanel controlPanel = new ControlPanel();
view.setModel(model);
view.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mEvt) {
Point p = mEvt.getPoint();
int row = view.getRow(p);
int col = view.getColumn(p);
model.selectSquare(col, row);
}
});
model.addPropertyChangeListener(BoardModel.BOARD, new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent e) {
view.repaint();
String moveCount = "" + model.getNumOfMoves();
controlPanel.setMoveCountFieldText(moveCount);
}
});
model.addPropertyChangeListener(BoardModel.WIN, new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ((boolean) evt.getNewValue()) {
String message = "Move count: " + model.getNumOfMoves();
String title = "Game Over";
int messageType = JOptionPane.PLAIN_MESSAGE;
JOptionPane.showMessageDialog(view, message, title, messageType);
}
}
});
controlPanel.setResetAction(new AbstractAction("Reset") {
#Override
public void actionPerformed(ActionEvent e) {
model.reset();
}
});
JFrame frame = new JFrame("Game");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(view);
frame.add(controlPanel, BorderLayout.PAGE_START);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
#SuppressWarnings("serial")
class ControlPanel extends JPanel {
private JTextField moveCountField = new JTextField("0", 10);
private JButton resetButton = new JButton();
public ControlPanel() {
add(new JLabel("Move Count:"));
add(moveCountField);
add(resetButton);
}
public void setResetAction(Action action) {
resetButton.setAction(action);
}
public void setMoveCountFieldText(String text) {
moveCountField.setText(text);
}
}
#SuppressWarnings("serial")
class BoardPanel extends JPanel {
private static final int PREF_W = 640;
private static final int PREF_H = PREF_W;
private BoardModel model;
private Color[] colors;
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
} else {
return new Dimension(PREF_W, PREF_H);
}
}
public void setModel(BoardModel model) {
this.model = model;
colors = new Color[model.getNumColors()];
// create colors.length Colors, all of different hue
for (int i = 0; i < colors.length; i++) {
float hue = (float) i / colors.length;
colors[i] = Color.getHSBColor(hue, 1f, 1f);
}
}
// translate point to logical square position
int getRow(Point p) {
return (p.y * model.getBoard().length) / getHeight();
}
int getColumn(Point p) {
return (p.x * model.getBoard()[0].length) / getWidth();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g); // always call the super's method
if (model == null) {
return;
}
int board[][] = model.getBoard();
int height = getHeight() / board.length;
int width = getWidth() / board[0].length;
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
Color color = colors[board[i][j]];
g.setColor(color);
int x = (j * getWidth()) / board[0].length;
int y = (i * getHeight()) / board.length;
g.fillRect(x, y, width, height);
}
}
}
}
class BoardModel {
public static final String BOARD = "board";
public static final String WIN = "win";
private int[][] board;
private int numColors;
private Random random = new Random();
private SwingPropertyChangeSupport support = new SwingPropertyChangeSupport(this);
private int numOfMoves = 0;
private boolean win = false;
public BoardModel(int size, int numColors) {
board = new int[size][size];
this.numColors = numColors;
reset();
}
public void reset() {
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
board[i][j] = random.nextInt(numColors);
}
}
numOfMoves = 0;
support.firePropertyChange(BOARD, null, board);
setWin(false);
}
public int[][] getBoard() {
return board;
}
public int getNumOfMoves() {
return numOfMoves;
}
public int getNumColors() {
return numColors;
}
public void setWin(boolean win) {
boolean oldValue = this.win;
boolean newValue = win;
this.win = win;
support.firePropertyChange(WIN, oldValue, newValue);
}
public boolean isWin() {
return win;
}
public void selectSquare(int x, int y) {
int replacementValue = board[y][x];
int targetValue = board[0][0];
if (targetValue == replacementValue) {
return;
} else {
recursiveMove(0, 0, targetValue, replacementValue);
numOfMoves++;
support.firePropertyChange(BOARD, null, board);
setWin(checkForWin());
}
}
public boolean checkForWin() {
int value = board[0][0];
for (int[] row : board) {
for (int cell : row) {
if (cell != value) {
return false;
}
}
}
return true;
}
private void recursiveMove(int i, int j, int targetValue, int replacementValue) {
int currentValue = board[i][j];
if (currentValue != targetValue || currentValue == replacementValue) {
return;
}
board[i][j] = replacementValue;
int rowMin = Math.max(0, i - 1);
int rowMax = Math.min(board.length - 1, i + 1);
int colMin = Math.max(0, j - 1);
int colMax = Math.min(board[i].length - 1, j + 1);
for (int i2 = rowMin; i2 <= rowMax; i2++) {
if (i2 != i) {
recursiveMove(i2, j, targetValue, replacementValue);
}
}
for (int j2 = colMin; j2 <= colMax; j2++) {
if (j2 != j) {
recursiveMove(i, j2, targetValue, replacementValue);
}
}
}
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
support.addPropertyChangeListener(propertyName, listener);
}
}

Keybind action being run at start but not from actual key press

I'm coding a game for my final project in Java, our teacher provided us with a Board class that is a component that allows us to place and remove pegs on a virtual game board instead of having to code one ourselves. I'm trying to add Key Binding to the Board component but the action I want performed on key press is happening when I run the program but It won't run when I type a Key.
The board class already has a method for getting the position clicked on the component and I think this might be interfering with my Code but I'm not sure.
This is my game class where I tried to add keybinding
package rpgGame;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JComponent;
import javax.swing.KeyStroke;
public class RPGGame
{
public static final GameWorld WORLD_MAP = new GameWorld();
public static Board LOCAL_MAP = new Board(20,50);
public static List<Mobile> allMobs = new ArrayList<Mobile>();
public static final Player PLAYER = new Player();
public static int xIndex = ((GameWorld.WORLD_SIZE-1)/2) - (50/2);
public static int yIndex = ((GameWorld.WORLD_SIZE-1)/2) - (20/2);
public static boolean boardUpdate = true;
public enum Direction {RIGHT,LEFT,UP,DOWN}
private static final String MOVE_PLAYER_UP = "move up";
private static final String MOVE_PLAYER_LEFT = "move left";
private static final String MOVE_PLAYER_RIGHT = "move right";
private static final String MOVE_PLAYER_DOWN = "move down";
public static final Thread SYNC_BOARD = new Thread()
{
public synchronized void run()
{
while (boardUpdate)
{
for (int i = 0; i < 50; i++)
{
for (int j = 0; j < 20; j++)
{
if (WORLD_MAP.isOccupied(i+xIndex, j+yIndex))
{
LOCAL_MAP.putPeg(Color.RED, j, i);
System.out.println("Successfully Updated");
}
else
{
LOCAL_MAP.putPeg(Color.GRAY, j,i);
}
}
}
boardUpdate = false;
}
}
};
public RPGGame()
{
generateMobs(200);
placeMobs();
placePlayer();
SYNC_BOARD.run();
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), MOVE_PLAYER_UP);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), MOVE_PLAYER_UP);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), MOVE_PLAYER_LEFT);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0), MOVE_PLAYER_LEFT);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), MOVE_PLAYER_RIGHT);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0), MOVE_PLAYER_RIGHT);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), MOVE_PLAYER_DOWN);
LOCAL_MAP.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0), MOVE_PLAYER_DOWN);
LOCAL_MAP.getActionMap().put(MOVE_PLAYER_UP, new MoveAction(Direction.UP));
LOCAL_MAP.getActionMap().put(MOVE_PLAYER_LEFT, new MoveAction(Direction.LEFT));
LOCAL_MAP.getActionMap().put(MOVE_PLAYER_RIGHT, new MoveAction(Direction.RIGHT));
LOCAL_MAP.getActionMap().put(MOVE_PLAYER_DOWN, new MoveAction(Direction.DOWN));
}
public static void main(String[] args)
{
new RPGGame();
}
public static void generateMobs(int numOfMobs)
{
for (int i=0; i<numOfMobs; i++)
{
allMobs.add(new Mobile());
}
}
public static void generateMobs()
{
int numOfMobs = (int)(Math.random()*500);
for (int i=0;i<numOfMobs; i++)
{
allMobs.add(new Mobile());
}
}
public static void placeMobs()
{
for (int i=0; i<allMobs.size(); i++)
{
//i is used as a placeholder value for points until I create a random number generator.
WORLD_MAP.placeCharacter(i, i,allMobs.get(i));
allMobs.get(i).setLocation(i, i);
}
}
public static void placePlayer()
{
WORLD_MAP.placeCharacter(249, 249, PLAYER);
PLAYER.setLocation(249, 249);
}
#SuppressWarnings("serial")
public class MoveAction extends AbstractAction
{
Direction direction;
public MoveAction(Direction direction)
{
if (direction.equals(Direction.RIGHT))
{
int x = PLAYER.getX();
int y = PLAYER.getY();
WORLD_MAP.moveCharacter(x+1, y, x, y);
PLAYER.move(1, 0);
boardUpdate = true;
System.out.println("MOVE RIGHT");
}
if (direction.equals(Direction.LEFT))
{
int x = PLAYER.getX();
int y = PLAYER.getY();
WORLD_MAP.moveCharacter(x, y, x-1, y);
PLAYER.move(-1, 0);
boardUpdate = true;
System.out.println("MOVE LEFT");
}
if (direction.equals(Direction.UP))
{
int x = PLAYER.getX();
int y = PLAYER.getY();
WORLD_MAP.moveCharacter(x, y, x, y+1);
PLAYER.move(0, 1);
boardUpdate = true;
System.out.println("MOVE UP");
}
if (direction.equals(Direction.DOWN))
{
int x = PLAYER.getX();
int y = PLAYER.getY();
WORLD_MAP.moveCharacter(x, y, x, y-1);
PLAYER.move(0, -1);
boardUpdate = true;
System.out.println("MOVE DOWN");
}
}
#Override
public void actionPerformed(ActionEvent e)
{
}
}
}
This is the Board class
package rpgGame;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
/** Board GUI for implementation with various games
* Author: Kirill Levin, Troy Vasiga, Chris Ingram
*/
#SuppressWarnings("serial")
public class Board extends JPanel
{
private static final int X_DIM = 60;
private static final int Y_DIM = 60;
private static final int X_OFFSET = 30;
private static final int Y_OFFSET = 30;
private static final double MIN_SCALE = 0.25;
private static final int GAP = 10;
private static final int FONT_SIZE = 16;
// Grid colours
private static final Color GRID_COLOR_A = new Color(153,255,102);
private static final Color GRID_COLOR_B = new Color(136,255,77);
private Color[][] grid;
private Point lastClick; // How the mouse handling thread communicates
// to the board where the last click occurred
private String message = "";
private int numLines = 0;
private double[][] line = new double[4][100]; // maximum number of lines is 100
private int columns, rows;
private int originalWidth;
private int originalHeight;
private double scale;
/** A constructor to build a 2D board.
*/
public Board (int rows, int columns)
{
super( true );
JFrame boardFrame = new JFrame( "Board game" );
this.columns = columns;
this.rows = rows;
originalWidth = 2*X_OFFSET+X_DIM*columns;
originalHeight = 2*Y_OFFSET+Y_DIM*rows+GAP+FONT_SIZE;
this.setPreferredSize( new Dimension( originalWidth, originalHeight ) );
boardFrame.setResizable(true);
this.grid = new Color[columns][rows];
this.addMouseListener(
new MouseInputAdapter()
{
/** A method that is called when the mouse is clicked
*/
public void mouseClicked(MouseEvent e)
{
int x = (int)e.getPoint().getX();
int y = (int)e.getPoint().getY();
// We need to by synchronized to the parent class so we can wake
// up any threads that might be waiting for us
synchronized(Board.this)
{
int curX = (int)Math.round(X_OFFSET*scale);
int curY = (int)Math.round(Y_OFFSET*scale);
int nextX = (int)Math.round((X_OFFSET+X_DIM*grid.length)*scale);
int nextY = (int)Math.round((Y_OFFSET+Y_DIM*grid[0].length)*scale);
// Subtract one from high end so clicks on the black edge
// don't yield a row or column outside of board because of
// the way the coordinate is calculated.
if (x >= curX && y >= curY && x < nextX && y < nextY)
{
lastClick = new Point(y,x);
// Notify any threads that would be waiting for a mouse click
Board.this.notifyAll() ;
} /* if */
} /* synchronized */
} /* mouseClicked */
} /* anonymous MouseInputAdapater */
);
boardFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
boardFrame.setContentPane( this );
boardFrame.pack();
boardFrame.setVisible(true);
}
/** A constructor to build a 1D board.
*/
public Board (int cols)
{
this(1, cols);
}
private void paintText(Graphics g)
{
g.setColor( this.getBackground() );
g.setFont(new Font(g.getFont().getFontName(), Font.ITALIC+Font.BOLD, (int)(Math.round(FONT_SIZE*scale))));
int x = (int)Math.round(X_OFFSET*scale);
int y = (int)Math.round((Y_OFFSET+Y_DIM*grid[0].length)*scale + GAP ) ;
g.fillRect(x,y, this.getSize().width, (int)Math.round(GAP+FONT_SIZE*scale) );
g.setColor( Color.black );
g.drawString(message, x, y + (int)Math.round(FONT_SIZE*scale));
}
private void paintGrid(Graphics g)
{
for (int i = 0; i < this.grid.length; i++)
{
for (int j = 0; j < this.grid[i].length; j++)
{
if ((i%2 == 0 && j%2 != 0) || (i%2 != 0 && j%2 == 0))
g.setColor(GRID_COLOR_A);
else
g.setColor(GRID_COLOR_B);
int curX = (int)Math.round((X_OFFSET+X_DIM*i)*scale);
int curY = (int)Math.round((Y_OFFSET+Y_DIM*j)*scale);
int nextX = (int)Math.round((X_OFFSET+X_DIM*(i+1))*scale);
int nextY = (int)Math.round((Y_OFFSET+Y_DIM*(j+1))*scale);
int deltaX = nextX-curX;
int deltaY = nextY-curY;
g.fillRect( curX, curY, deltaX, deltaY );
Color curColour = this.grid[i][j];
if (curColour != null) // Draw pegs if they exist
{
g.setColor(curColour);
g.fillOval(curX+deltaX/4, curY+deltaY/4, deltaX/2, deltaY/2);
}
}
}
((Graphics2D) g).setStroke( new BasicStroke(0.5f) );
g.setColor(Color.BLACK);
int curX = (int)Math.round(X_OFFSET*scale);
int curY = (int)Math.round(Y_OFFSET*scale);
int nextX = (int)Math.round((X_OFFSET+X_DIM*grid.length)*scale);
int nextY = (int)Math.round((Y_OFFSET+Y_DIM*grid[0].length)*scale);
g.drawRect(curX, curY, nextX-curX, nextY-curY);
}
private void drawLine(Graphics g)
{
for (int i =0; i < numLines; i++ )
{
((Graphics2D) g).setStroke( new BasicStroke( 5.0f*(float)scale) );
g.drawLine( (int)Math.round((X_OFFSET+X_DIM/2.0+line[0][i]*X_DIM)*scale),
(int)Math.round((Y_OFFSET+Y_DIM/2.0+line[1][i]*Y_DIM)*scale),
(int)Math.round((X_OFFSET+X_DIM/2.0+line[2][i]*X_DIM)*scale),
(int)Math.round((Y_OFFSET+Y_DIM/2.0+line[3][i]*Y_DIM)*scale) );
}
}
/**
* Convert a String to the corresponding Color defaulting to Black
* with an invald input
*/
/*private Color convertColour( String theColour )
{
for( int i=0; i<COLOUR_NAMES.length; i++ )
{
if( COLOUR_NAMES[i].equalsIgnoreCase( theColour ) )
return COLOURS[i];
}
return DEFAULT_COLOUR;
}*/
/** The method that draws everything
*/
public void paintComponent( Graphics g )
{
this.setScale();
this.paintGrid(g);
this.drawLine(g);
this.paintText(g);
}
public void setScale()
{
double width = (0.0+this.getSize().width) / this.originalWidth;
double height = (0.0+this.getSize().height) / this.originalHeight;
this.scale = Math.max( Math.min(width,height), MIN_SCALE );
}
/** Sets the message to be displayed under the board
*/
public void displayMessage(String theMessage)
{
message = theMessage;
this.repaint();
}
/** This method will save the value of the colour of the peg in a specific
* spot. theColour is restricted to
* "yellow", "blue", "cyan", "green", "pink", "white", "red", "orange"
* Otherwise the colour black will be used.
*/
public void putPeg(Color colour, int row, int col)
{
this.grid[col][row] = colour;
this.repaint();
}
/** Same as putPeg above but for 1D boards
*/
public void putPeg(Color colour, int col)
{
this.putPeg(colour, 0, col );
}
/** Remove a peg from the gameboard.
*/
public void removePeg(int row, int col)
{
this.grid[col][row] = null;
repaint();
}
/** Same as removePeg above but for 1D boards
*/
public void removePeg(int col)
{
this.grid[col][0] = null;
repaint();
}
/** Draws a line on the board using the given co-ordinates as endpoints
*/
public void drawLine(double row1, double col1, double row2, double col2)
{
this.line[0][numLines]=col1;
this.line[1][numLines]=row1;
this.line[2][numLines]=col2;
this.line[3][numLines]=row2;
this.numLines++;
repaint();
}
/** Removes one line from a board given the co-ordinates as endpoints
* If there is no such line, nothing happens
* If multiple lines, all copies are removed
*/
public void removeLine(int row1, int col1, int row2, int col2)
{
int curLine = 0;
while (curLine < this.numLines)
{
// Check for either endpoint being specified first in our line table
if ( (line[0][curLine] == col1 && line[1][curLine] == row1 &&
line[2][curLine] == col2 && line[3][curLine] == row2) ||
(line[2][curLine] == col1 && line[3][curLine] == row1 &&
line[0][curLine] == col2 && line[1][curLine] == row2) )
{
// found a matching line: overwrite with the last one
numLines--;
line[0][curLine] = line[0][numLines];
line[1][curLine] = line[1][numLines];
line[2][curLine] = line[2][numLines];
line[3][curLine] = line[3][numLines];
curLine--; // perhaps the one we copied is also a match
}
curLine++;
}
repaint();
}
/** Waits for user to click somewhere and then returns the click.
*/
public Point getClick()
{
Point returnedClick = null;
synchronized(this) {
lastClick = null;
while (lastClick == null)
{
try {
this.wait();
} catch(Exception e) {
// We'll never call Thread.interrupt(), so just consider
// this an error.
e.printStackTrace();
System.exit(-1) ;
} /* try */
}
int x = (int)Math.floor((lastClick.getY()-X_OFFSET*scale)/X_DIM/scale);
int y = (int)Math.floor((lastClick.getX()-Y_OFFSET*scale)/Y_DIM/scale);
// Put this into a new object to avoid a possible race.
returnedClick = new Point(x,y);
}
return returnedClick;
}
/** Same as getClick above but for 1D boards
*/
public double getPosition()
{
return this.getClick().getY();
}
public int getColumns()
{
return this.columns;
}
public int getRows()
{
return this.rows;
}
}

You're shooting yourself in the foot with that thread code -- you're calling run() not start() on it
SYNC_BOARD.run();
This will run on the Swing event thread and risks completely freezing your GUI.
As a general rule, you should almost never extend Thread but rather implement Runnable, but regardless, don't use that Thread code -- Instead use a Swing Timer since your code has no breaks in it, no Thread.sleeps and it will make your CPU awfully busy, and the Swing Timer will help make sure that your code obeys Swing threading rules.
Also your MoveAction is wrong. Most of that code should go in the actionPerformed method. The constructor should just set the direction field and that's it.
Something like:
#SuppressWarnings("serial")
public class MoveAction extends AbstractAction {
Direction direction;
public MoveAction(Direction direction) {
// this is the only code the constructor should have!
this.direction = direction;
}
#Override
public void actionPerformed(ActionEvent e) {
// use direction to help make move in here
}
}
Understand that this is likely causing some major problems, since the constructor is called on program creation (hence your key bindings "work" when the program starts), but it's the actionPerformed that actually gets called when the right key is pressed.

how to create multiple VerticalFieldManager dynamically Blackberry

I've been struggling to create multiple VerticalFieldManager dynamically on Blackberry. Each subManager will show different data to the user. And each subManager will have a different position on the screen. So i created a class which has a "mainManager" and another class which creates the "submanagers" then i call mainManager.add(new TheClassExtendingVerticalFieldManager); to add the subManagers to the mainManager. The problem is that i only get one subManager instead of three. I'm using padding to separate the managers. Here's the code im using. Please guide me in the right direction, it would be much appreciated.
The class that creates the submanager
public class ProgramListView extends VerticalFieldManager{
private VerticalFieldManager subManager;
private int _height;
public ProgramListView(int height){
this._height = height;
// subManager = new VerticalFieldManager(
// Manager.NO_HORIZONTAL_SCROLL | Manager.NO_VERTICAL_SCROLL | Manager.NO_VERTICAL_SCROLLBAR |
// Manager.NO_HORIZONTAL_SCROLLBAR | Manager.USE_ALL_WIDTH)
//
// {
//
//
// };
}
public int get_height() {
return _height;
}
public void set_height(int _height) {
this._height = _height;
}
public void setCoordinates(int x, int y){
setPosition(100,140);
}
protected void sublayout(int maxWidth, int maxHeight)
{
int displayWidth = Display.getWidth();
int displayHeight = maxHeight;
this.setPosition(300, 300);
super.sublayout( 40, 40);
setPadding(this.get_height(), 0, 0, 0);
setExtent(displayWidth, this.get_height());
}
public void paint(Graphics graphics)
{
graphics.setBackgroundColor(Color.BLUE);//blue
graphics.clear();
super.paint(graphics);
}
public int getPreferredWidth() {
// TODO Auto-generated method stub
return Display.getWidth();
}
}
The mainManager class
public class ProgramLayout extends MainScreen {
private HorizontalFieldManager mainManager;
private int deviceWidth = Display.getWidth();
private int deviceHeight = Display.getHeight();
private Vector subManagers;
private int theheight;
public ProgramLayout(){
setToolbar();
subManagers = new Vector();
theheight = 100;
mainManager = new HorizontalFieldManager(Manager.VERTICAL_SCROLL | Manager.USE_ALL_WIDTH | Manager.USE_ALL_HEIGHT)
{
protected void sublayout(int maxWidth, int maxHeight)
{
int displayWidth = deviceWidth;
int displayHeight = deviceHeight;
super.sublayout( displayWidth, displayHeight);
setExtent(displayWidth, displayHeight);
}
public void paint(Graphics graphics)
{
graphics.setBackgroundColor(Color.BLACK);
graphics.clear();
super.paint(graphics);
}
public int getPreferredWidth() {
// TODO Auto-generated method stub
return Display.getWidth();
}
};
for (int i = 0; i < 3; i++) {
theheight = theheight+100;
subManagers.addElement(new ProgramListView(theheight));
}
for (int i = 0; i < subManagers.size(); i++) {
mainManager.add((VerticalFieldManager)subManagers.elementAt(i));
}
this.add(mainManager);
}
Thanks in advance

try this:
for (int i = 0; i < 3; i++) {
theheight = theheight+100;
mainManager.add(new ProgramListView(theheight));
}
this.add(mainManager);

Just to elaborate on what Eugen Martynov pointed out, your mainManager is a HorizontalFieldManager, which means it will lay out child fields in the order that you add() them, horizontally. It automatically handles layout for you, based on the order of calls you make to add().
But, each child is an instance of ProgramListView and returns Display.getWidth() in
getPreferredWidth():
public int getPreferredWidth() {
// TODO Auto-generated method stub
return Display.getWidth();
}
So, the first one takes up the whole screen width, and the next two would have to be to the right of that (but you've already taken up the whole screen width).
Did you want these three ProgramListViews to be stacked vertically? Then, mainManager should just be changed to a VerticalFieldManager. With a VerticalFieldManager, calling add() for three different ProgramListView child fields will automatically lay them out vertically.

ListField display image from URL

I am displaying a customized list field with text on the right side and image on the left side.The image comes from a URL dynamically. Initially i am placing a blank image on the left of the list field,then call URLBitmapField class's setURL method,which actually does the processing and places the processed image on top of the blank image.The image gets displayed on the list field,but to see that processed image i need to click on the list field image.I want the processed image to be displayed automatically in the list field after the processing.Can anyone tell me where i am getting wrong?I have been asking for help,but no one seems to figure out the problem.Any productive suggestions would be appreciated
import java.util.Vector;
import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.ContextMenu;
import net.rim.device.api.ui.DrawStyle;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.BitmapField;
import net.rim.device.api.ui.component.Dialog;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.ListField;
import net.rim.device.api.ui.component.ListFieldCallback;
import net.rim.device.api.ui.component.NullField;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.util.Arrays;
import net.rim.device.api.ui.component.ListField;
public class TaskListField extends UiApplication {
// statics
// ------------------------------------------------------------------
public static void main(String[] args) {
TaskListField theApp = new TaskListField();
theApp.enterEventDispatcher();
}
public TaskListField() {
pushScreen(new TaskList());
}
}
class TaskList extends MainScreen implements ListFieldCallback {
private Vector rows;
private Bitmap p1;
private Bitmap p2;
private Bitmap p3;
String Task;
ListField listnew = new ListField();
private VerticalFieldManager metadataVFM;
TableRowManager row;
public TaskList() {
super();
URLBitmapField artistImgField;
listnew.setRowHeight(80);
listnew.setCallback(this);
rows = new Vector();
for (int x = 0; x <3; x++) {
row = new TableRowManager();
artistImgField = new URLBitmapField(Bitmap
.getBitmapResource("res/images/bg.jpg"));
row.add(artistImgField);
String photoURL = "someimagefrmurl.jpg";
Log.info(photoURL);
// strip white spaces in the url, which is causing the
// images to not display properly
for (int i = 0; i < photoURL.length(); i++) {
if (photoURL.charAt(i) == ' ') {
photoURL = photoURL.substring(0, i) + "%20"
+ photoURL.substring(i + 1, photoURL.length());
}
}
Log.info("Processed URL: " + photoURL);
artistImgField.setURL(photoURL);
LabelField task = new LabelField("Display");
row.add(task);
LabelField task1 = new LabelField(
"Now Playing" + String.valueOf(x));
Font myFont = Font.getDefault().derive(Font.PLAIN, 12);
task1.setFont(myFont);
row.add(task1);
rows.addElement(row);
}
listnew.setSize(rows.size());
this.add(listnew);
//listnew.invalidate();
}
// ListFieldCallback Implementation
public void drawListRow(ListField listField, Graphics g, int index, int y,
int width) {
TableRowManager rowManager = (TableRowManager) rows.elementAt(index);
rowManager.drawRow(g, 0, y, width, listnew.getRowHeight());
}
protected void drawFocus(Graphics graphics, boolean on) {
}
private class TableRowManager extends Manager {
public TableRowManager() {
super(0);
}
// Causes the fields within this row manager to be layed out then
// painted.
public void drawRow(Graphics g, int x, int y, int width, int height) {
// Arrange the cell fields within this row manager.
layout(width, height);
// Place this row manager within its enclosing list.
setPosition(x, y);
// Apply a translating/clipping transformation to the graphics
// context so that this row paints in the right area.
g.pushRegion(getExtent());
// Paint this manager's controlled fields.
subpaint(g);
g.setColor(0x00CACACA);
g.drawLine(0, 0, getPreferredWidth(), 0);
// Restore the graphics context.
g.popContext();
}
// Arrages this manager's controlled fields from left to right within
// the enclosing table's columns.
protected void sublayout(int width, int height) {
// set the size and position of each field.
int fontHeight = Font.getDefault().getHeight();
int preferredWidth = getPreferredWidth();
// start with the Bitmap Field of the priority icon
Field field = getField(0);
layoutChild(field, 146,80);
setPositionChild(field, 0, 0);
// set the task name label field
field = getField(1);
layoutChild(field, preferredWidth - 16, fontHeight + 1);
setPositionChild(field, 149, 3);
// set the list name label field
field = getField(2);
layoutChild(field, 150, fontHeight + 1);
setPositionChild(field, 149, fontHeight + 6);
setExtent(360, 480);
}
// The preferred width of a row is defined by the list renderer.
public int getPreferredWidth() {
return listnew.getWidth();
}
// The preferred height of a row is the "row height" as defined in the
// enclosing list.
public int getPreferredHeight() {
return listnew.getRowHeight();
}
}
public Object get(ListField listField, int index) {
// TODO Auto-generated method stub
return null;
}
public int getPreferredWidth(ListField listField) {
return 0;
}
public int indexOfList(ListField listField, String prefix, int start) {
// TODO Auto-generated method stub
return 0;
}
}

Finally i solved it of my own. This worked:
UiApplication.getUiApplication().invokeLater(
new Runnable() {
public void run() {
listnew.invalidate();
}
},500,true);