Trying to draw multiple bars

Question

Hi I'm pretty new to this but here's my question.
I have a Panel and I need to draw around 20 bars or rectangles on there.
So I made an array of rectangles and figured a for loop should work .
But after I run it my frame will pop up but none of my buttons will
show up and I keep getting a null pointer execption and the program will just die.
Here's the piece of code that should get the job done, but keeps screwing up.
public void draw( Graphics g ) {
    for ( int i = 0; i < rectangles.length; i++ )
        rectangles.draw(g);
     g.setColor(c);
     int xc = (int) (5 + 100 * Math.sin(6.28*t/n));
     int yc = (int) (5 + 100 * Math.sin(6.28*t/n));
     g.fillRect(xc, yc, sz, siz);
Can somebody help me figure out where I'm screwing up?
Thanks alot

Answer 1

Hard to tell from this code. I'd have a wild guess
and say the array has holes in it. Does
rectangles[0] have a value for example? Inside the
loop put System.out.println("i="+i);  and see how far it get before it blows up.Thanks dude but unfornatly it does the same thing.
As far whether rectangles[0] have a value, I assumed when I wrote
the loop that as long as it increments to the end of the array it would keep drawing
rectangles, so rectangles[0] should be the very first bar that's drawn, unless I royaly
screwed up somewhere.
Here's the class that houses that piece of code.
public class AnimatedSquare implements Animator {
        private int sz; // this is to determine the width
        private int siz;//for the height
        private Color c;
        private int n;
        private Animation[] rectangles;
        public AnimatedSquare(int sz1, Color c1, int n1, int siz1) {
               sz = sz1;
               c = c1;
               n = n1;
               siz = siz1;
        public Animation getAnimation() {
               return new ASquare();
        public String brief() {return "Animated Square";}
        public String verbose() {return brief();};
        private class ASquare implements Animation {
               private double t;
               public ASquare() {
                    t = 0;
              rectangles = new Animation[30]; // 30 rectangles
            public void draw( Graphics g ) {
                     for ( int i = 0; i < rectangles.length; i++ )
                   rectangles.draw(g);
               g.setColor(c);
                    int xc = (int) (5 + 100 * Math.sin(6.28*t/n));
                    int yc = (int) (5 + 100 * Math.sin(6.28*t/n));
               g.fillRect(xc, yc, sz, siz);
          public Animation next() {
               t = t + 1;
               return this;
          public String brief() { return "Square " + t;};
          public String verbose() {return brief();}