Weird error not sure what Im doing wrong

[Keshan Pillay]

Hi everyone! I'm doing an assignment for university (compsci 101), where I have to program a simple 2d game. So I chose brick, (the one with the ball and the paddle) and I've gotten this far.

 import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
 
public class GUIJPanel extends JPanel implements ActionListener {
 

private Point position;
private Timer t;
private int movementx;
private int movementy;
private Rectangle leftBorder;
private Rectangle rightBorder;
private Rectangle topBorder;
private Rectangle bottomBorder;
private int timer;
private Rectangle paddle;
private final int RECTANGLE_WIDTH = 50;
private final int RECTANGLE_HEIGHT = 25;
Rectangle[] row1OfBricks;
Rectangle[] row2OfBricks;
Rectangle[] row3OfBricks;
Rectangle testRect;
 

 

 

 

 
public GUIJPanel() {
 
position = new Point(170,300);
movementx = 5;
movementy = -5;
testRect = new Rectangle(10,10,20,20);
 
Rectangle[] row1OfBricks;
Rectangle[] row2OfBricks;
Rectangle[] row3OfBricks;
row1OfBricks = new Rectangle [7];
row2OfBricks = new Rectangle [7];
row3OfBricks = new Rectangle [7];
int xValue;
int yValue;
xValue = 45;
for (int i = 0; i < row1OfBricks.length; i++) {
 
yValue = 25;
row1OfBricks[i] = new Rectangle(xValue, yValue, RECTANGLE_WIDTH, RECTANGLE_HEIGHT);
xValue += 60;
}
xValue = 45;
for (int i = 0; i < row2OfBricks.length; i++) {
 
yValue = 60;
row2OfBricks[i] = new Rectangle(xValue, yValue, RECTANGLE_WIDTH, RECTANGLE_HEIGHT);
xValue += 60;
}
xValue = 45;
for (int i = 0; i < row3OfBricks.length; i++) {
 
yValue = 95;
row3OfBricks[i] = new Rectangle(xValue, yValue, RECTANGLE_WIDTH, RECTANGLE_HEIGHT);
xValue += 60;
}
xValue = 45;
for (int i = 0; i < row3OfBricks.length; i++) {
System.out.println(row1OfBricks[i].x + " " + row1OfBricks[i].y + " " + row1OfBricks[i].width+ " " +row1OfBricks[i].height);
}
for (int i = 0; i < row3OfBricks.length; i++) {
System.out.println(row2OfBricks[i].x + " " + row2OfBricks[i].y + " " + row2OfBricks[i].width+ " " +row2OfBricks[i].height);
}
for (int i = 0; i < row3OfBricks.length; i++) {
System.out.println(row3OfBricks[i].x + " " + row3OfBricks[i].y + " " + row3OfBricks[i].width+ " " +row3OfBricks[i].height);
}
 

 

 

 

 

leftBorder =new Rectangle(-100,0,100,390);
 rightBorder =new Rectangle(403,0,500,390);
topBorder =new Rectangle(-1,-20,403,19);
bottomBorder = new Rectangle(0,400,403, 200);
paddle = new Rectangle(155,390, 90, 10);
t = new Timer(25, this);
t.start();
 

 

 

 

 

 

 
}
 

 
public void actionPerformed(ActionEvent e) {
 if (leftBorder.contains(position)) {
 movementx *= -1;
 System.out.println("Test1");
 movementx += (int)(Math.random()*2);
 
 }
 if (rightBorder.contains(position)) {
 movementx *= -1;
 System.out.println("Test2");
  movementx += (int)(Math.random()*2);
 
 }
 if (topBorder.contains(position)) {
 movementy *= -1;
 System.out.println("Test3");
  movementy += (int)(Math.random()*2);
 
 }
 if (bottomBorder.contains(position)) {
  movementy *= -1;
  System.out.println("Test3");
   movementy += (int)(Math.random()*2);
 }
 if (paddle.contains(position)) {
   movementy *= -1;
   System.out.println("Test3");
   movementy += (int)(Math.random()*2);
 }
 

 

position.y += movementy;
position.x += movementx;
 

 
repaint();
}
 

 

 
public void paintComponent(Graphics g){
super.paintComponent(g);
 
g.setColor(Color.pink);
System.out.println(row1OfBricks[1].x);
g.fillRect(testRect.x,testRect.y,testRect.width,testRect.height);
 

 

 

 
g.fillRect(155,390, 90, 10);
g.setColor(Color.red);
g.fillOval(position.x, position.y, 20, 20);
//g.drawRect(0,0,403,390); //border
//g.drawRect(-1,0,1,390);
//g.drawRect(403,0,1,390);
//g.drawRect(-1,-1,403,1);
//g.drawRect(0,400,403, 1);
 

 

}
 
}
   

What I'm trying to do here is to make the 3 arrays row1OfBricks, row2OfBricks and row3Ofbricks, then I want to draw the rectangles stored in these arrays in the paintComponent method. The arrays are initialized correctly, and the values they all store are all correct. But when I try an use something like row1OfBricks[1].x in the paintcomponent method, to access the x value of the rectangle in position 1 of the array, I get this mega error that streams down the console and doesn't stop.
When I try and access row1OfBricks[1].x anywhere else, it returns the correct value.
But in the paintcomponent method ive put in
System.out.println(row1OfBricks[1].x);
just as a test, and it errors.

Any help would be appreciated.

[Joanne Neal]

You've got row1OfBricks defined twice - once as an instance variable and once as a local variable in the GUIJPanel constuctor, so the constructor will initialise the local variable, but the paintComponent method will use the instance variable that has not been initialised.

[Keshan Pillay]

omg wow, thanks so much! I feel stupid for not catching that myself.

[Campbell Ritchie]

And welcome to JavaRanch.

It takes quite a lot of experience to pick up that sort of mistake.

[Keshan Pillay]

Thank you very much for the kind welcome, I'm sure I'll be spending a lot of time here ^^