[RESOLVED] What's wrong?

I'm really stuck and don't know what to do

Code:

---

public Block (int x, int y) {
    pt = new Point(x, y) ;
    color=colors[new Random().nextInt(colors.length)];
  }

---

This code is a constructor, my problem is in the second line "Random color"
it's supposed to select a random color for each block from an array containing 4 colors

here is how I call it:

Code:

---

for (int i = 0 ; i < blocks.length ; i++) {
      for (int j = 0 ; j < blocks[i].length ; j++) {
        blocks[i][j] = new Block(i*20, j*20) ;
      }
    }

---

my problem is, when I call it from the paint method (Applet) blocks[i][j].paint(g):

Code:

---

public void paint (Graphics g) {
    g.setColor(this.color) ;
    g.fill3DRect(pt.x, pt.y, 15, 15, true) ;
  }

---

All blocks are the same color, I tried adding System...print to check if the problem is in the paint but it's not, all randoms are the same value.
Any help would be great

My guess is that each new random object produces the same sequence of numbers (probably seeded using the current time). You should use a single random object for all blocks. Something like:

Code:

---

class MyRandom {
    private static Random random;
    public static int random(int max) {
        if (!random) random = new Random();
        return random.nextInt(max);
    }
}

---

You're "something like" got me banging my head..
But thank you for the idea (seeded using the current time). I didn't think of that

How many times are you calling this constructor? I assume it's once per block? The problem with a random number generator is that it's not really random. If you don't use the same random generator then you will probably get ALMOST identical results each time.

I would either make the random number generator static for the class, or wherever you have this code:

Code:

---

for (int i = 0 ; i < blocks.length ; i++) { 
    for (int j = 0 ; j < blocks[i].length ; j++) { 
              blocks[i][j] = new Block(i*20, j*20) ;
    }
}

---

Make the random number generator global and set the color through the loop:

Code:

---

Random r = new Random();
for (int i = 0 ; i < blocks.length ; i++) { 
    for (int j = 0 ; j < blocks[i].length ; j++) { 
              blocks[i][j] = new Block(i*20, j*20) ;
              blocks[i][j].setColor(colors[r.nextInt(colors.length)];
    }
}

---

That would require you take out some coding from your blocks class, so I don't know if you want to do that or not. Try making the random generator a static global variable and see what happens.

It might also be useful to know that the random generator (if the same object instance) will not select the same number twice unless all numbers have been touched once.

I've created a static Random for the Block class and it works now, thank you very much