如何创建两个相同但状态不同的对象

Question

I am trying to create at least two independent objects using the same class. Meaning that I want each of them to use the same class but use the variables in it independently. I am not sure if this is possible but that is why I am here.

The two skeletons (skeleton1 and skeleton2) are the two objects that I want to be independent of each other.

@Override
public void render(GameContainer gc, StateBasedGame gm, Graphics g)
        throws SlickException {

    background.draw(0, 0, Constants.WIN_WIDTH, Constants.WIN_HEIGHT);

    g.drawImage(ccb, mkX, mkY);

    Skeleton skeleton1 = new Skeleton(g, gm);
    Skeleton skeleton2 = new Skeleton(g, gm);

    score = new DeathScreenButton(scoreCounter, (Constants.WIN_WIDTH / 2) / 2, 0, g, Color.transparent);

}

More specifically, I want their x and y axis to be independent shown here (they are sX and sY):

public class Skeleton {

private Graphics g;
private StateBasedGame gm;

private int mkX = InGame.getmkX();
private int mkY = InGame.getmkY();

// This makes them spawn on each other :(
// "static" prevents them from popping around the screen
private static int sX = (int)(Math.random() * Constants.WIN_WIDTH) + 1;
private static int sY = (int)(Math.random() * Constants.WIN_HEIGHT) + 1;

private Image skele;

public Skeleton (Graphics g, StateBasedGame gm) {

    this.g = g;
    this.gm = gm;

    try {
        init();
    } catch (SlickException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

    render();

    try {
        update();
    } catch (SlickException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

Answer 1

Your Skeletons are independent already. One of Objected-Oriented programming purposes are class instances. This way, two instances of the same class may have the same attributes, but they will never be the same . It may be a little confusing in the beginning, but the objective is to develop reusable code, then you may instantiate 1..n Skeletons, and they will be independent.

Skeleton skel1 = new Skeleton(Graphics g, StateBasedGame gm);

Hope it was helpful. Thank you.

Answer 2

Write/Overwrite the update method, if you haven't already. Update your positions in that method.

Put the initialization of the variables sX and sY in the constructor.

Remove static . By marking sX and sY static , all instances of your class will always share these values, so you can never have to Skeletons with different coordinates. If you change the value for one instance, you change it for all instances.

same class but use the variables in it independently

That basically means: I want to use instance variables. Variables marked static are class variables.