ArrayList of my objects, indexOf problem

Question

I have problem with Java\'s ArrayList. I\'ve created an Object, that contains two attributes, x and y. Now I\'ve loaded some object in my ArrayList. Problem is that I don\'t

Answer 1

Is this what you looking for?

public class Point {

private final int x;
private final int y;

public Point(int x, int y) {
    this.x = x;
    this.y = y;
}

public int getX() {
    return x;
}

public int getY() {
    return y;
}

@Override
public boolean equals(Object o) {
    return (o instanceof Point && getX() == ((Point) o).getX() && getY() == ((Point) o)
            .getY());

}

}

public class TestIndexOf {

public static void main(String[] args){
    Point p1 = new Point(10,30);
    Point p2 = new Point(20,40);
    Point p3 = new Point(50,40);
    Point p4 = new Point(60,40);
    List list = new ArrayList();
    list.add(p1);
    list.add(p2);
    list.add(p3);
    list.add(p4);
    System.out.println(list.indexOf(p3));
}

}

If you just want to search on the x property, change the equals method to compare only the x values like:

@Override
public boolean equals(Object o) {
    return (o instanceof Point && getX() == ((Point) o).getX());

}