NullPointerException

[Jing Liang]

Hello guys,

I couldn't fix this NPE. Please Help. Thanks
In my playGame() method, I have

 
                       if(temp1==temp2)
{
repaint();
}
else
{repaint();

t= new Timer(2000, new GuessGame());
t.setRepeats(false);
t.start();
}   

I receive NPE from t.start();

Here are my program

 
 
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
import javax.swing.*;
 
public class GuessGame extends Applet implements ActionListener, MouseListener
{
  int  x,y;
  Box [][] boxes = new Box[4][4];
  Box boxChoice;
  Button newGame;
  Timer t;
  int col;
  int row;
  int initialBoxX = 50; 
  int initialBoxY = 50;
  int width = 50;
  int height = 50;
  Graphics g;
  int counter=0;
 Color itemp, temp1, temp2;
 
 int row1, col1, row2, col2;
 
public void init()
{
newGame = new Button("New Game");
        add(newGame);
newGame.addActionListener(this);

addMouseListener(this);
setBackground(Color.white);
        
setNewGame();
  }
  
 
public void setNewGame()
{
int chosenColors[] = {0,0,0,0,0,0,0,0};
int rint;
int localX, localY;
 
          for(int col = 0; col <=3; col++)
{
     
             for(int row = 0; row<=3; row++)
{
                
                localY = initialBoxY + row*height;
localX = initialBoxX + col*width;
                rint = (int)(Math.random() * 8);
                while (chosenColors[rint] >= 2)
                     {
rint = (int)(Math.random() * 8);
}
                chosenColors[rint] = chosenColors[rint] +1;
Color colorChoices[] = {Color.red,Color.blue,Color.cyan, Color.green, Color.magenta,Color.pink,Color.orange, Color.yellow};
                boxes[row][col] = new Box(localX, localY, height, width, colorChoices[rint]);

                }
             
       }
        repaint();
  }
 
public void paint(Graphics g) 
{
        displayGame(g);
  }
 
public void displayGame(Graphics g)
{  
         // go to each box and display it.
         for (int i = 0; i <= 3; i++) 
{
              for (int j = 0; j <= 3; j++)
{
             //System.out.println("display coordinates: row "+i+" column "+j);
              boxes[i][j].display(g);
              }
         }
 // now make the solid lines around the boxes
  
   }
 
  public void playGame()
  {

if(counter==3)
{
boxes[row1][col1].showColor=false;
counter=0;
repaint();
}
 
    if(counter==1)
{
temp1=itemp;
row1=row;
col1=col;
repaint();

}
if(counter==2)
{
row2=row;
col2=col;
 
if(row1==row2 && col1==col2)
{
counter=1;
return;
}
else
{
temp2=itemp;
counter=0;
}

if(temp1==temp2)
{
repaint();
}
else
{repaint();

t= new Timer(2000, new GuessGame());
t.setRepeats(false);
t.start();




}
}
  }
 
  public void actionPerformed(ActionEvent event)
  {
if(event.getSource()==newGame)
{
      setNewGame();
}
else
{
boxes[row1][col1].showColor=false;
boxes[row2][col2].showColor=false;
repaint();

}

  }
 
  public void mouseClicked(MouseEvent e)
  {
  }
  public void mouseEntered(MouseEvent e)
  {
  }
  public void mouseExited(MouseEvent e)
  {
  }
  public void mousePressed(MouseEvent e)
  {
  }
  public void mouseReleased(MouseEvent e)
  {
x=e.getX();
y=e.getY();
if((x>=initialBoxX && x<=4*width+initialBoxX)&&(y>=initialBoxY && y<=4*height+initialBoxY))
{
int rowSubscript = (y - initialBoxY)/height;
        int colSubscript = (x - initialBoxX)/width;
this.row=rowSubscript;
this.col=colSubscript;
if(boxes[rowSubscript][colSubscript].showColor==true)
{
counter=3;
playGame();
}
else
{
counter++;
itemp = boxes[rowSubscript][colSubscript].boxColor;
        boxes[rowSubscript][colSubscript].showColor=true;

playGame();

} 
}
else
{
}
  } 
 

 

 
class Box 
{
    int x, y; 
    int width;
    int height;
    Color boxColor;
    Graphics g;
    boolean showColor = false;  // this is a flag - it will later tell the box
                                // if it has been clicked or not
 
public Box(int X1,int Y1,int h ,int w, Color myColor)
{
        x = X1;
y = Y1;
height = h;
width = w;
boxColor = myColor;
   }
 
public void display(Graphics graph)
{
        g = graph;   
        if (showColor == false) 
{
            g.setColor(Color.gray);
            g.fillRect(x, y, height, width);
}
        else
{
     g.setColor(boxColor);
             g.fillRect(x, y, height, width);
}
    }
 
   public void picked()
   {
boxes[row][col].showColor=true;
   }
}
}
 
class Ticker implements ActionListener
{
GuessGame timer=new GuessGame();
boolean tick = true;
public void actionPerformed(ActionEvent eve)
{
timer.repaint();
}
 
}
 
  

[Jing Liang]

Problem solved thanks guys