Question

I am developing a Java game, and am currently writing a map maker. I can make the map and draw tiles, but i need to be able to change the position of those tiles so the character can see different locations of the map. When I try to change it, in the moveMap() method, It gives me this error:

Exception in thread "Thread-2" java.lang.ArrayIndexOutOfBoundsException: 570
at Base.moveMap(Base.java:88)
at Base.run(Base.java:55)
at java.lang.Thread.run(Unknown Source)

I have no idea why this is happening – could someone please help me understand the problem. Is there any alternate way to move the tiles?

Here is my code…

public class Base extends JPanel implements Runnable {

    private static String[] line = { 
        "wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwwwwwwwwwwwfffffffffffwwwwwwwwwww", 
        "wwwwwwffwwwwwwwwfwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwfffffffwwwfwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwffwwwffffffwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwffwwwffffffwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwfffffffwwwwwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwffwwwwwwwwwwwwwwwwwwwwwwwwwwwwww", 
        "wwwwwwffwwwwwwwwwwwwwwffffffffwwwwwwww",
        "wwwwwwffwwwwwwwwwwwwwwwwwwwwffwwwwwwww",
        "wwwwffffffwwwwwwwwwwwwwwwwwwffwwwwwwww",
        "wwwwffffffffffffffffffffffffffwwwwwwww",
        "wwwwffffffwwwwwwwwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww",
        "wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww",};

    private Rectangle[] colRect;

    private int tileWidth = 30;
    private int tileHeight = 30;

    public Base() {
        colRect = new Rectangle[line.length * line[0].length()];
        for (int i = 0; i < line.length; i++) {
            for (int f = 0; f < line[i].length(); f++) {
                colRect[counter] = new Rectangle(f * tileWidth, i * tileHeight,tileWidth, tileHeight);
                if (counter != colRect.length) {
                    counter += 1;
                }
            }
        }
    }

    public void moveMap(){
        for(int i = 0; i <= colRect.length; i++){
            colRect[i].setLocation(colRect[i].x+1, colRect[i].y+1);
        }
    }
}

Answer 1

You almost certainly mean this:

for (int i = 0; i < colRect.length; i++) {

Instead of this:

for(int i = 0; i <= colRect.length; i++){

Remember that if an array has length n, the indexes go from 0 to n – 1.