Static variable messing everything up

Question

Probably a very basic Java problem but I have two variables in a entity class:

public class Entity {

int posX;
int posY;

public Entity(int posX, int posY){
    this.posX = posX;
    this.posY = posY;
}

public void update(){

}

public void draw(Graphics2D g2d){

}

}

My player and enemy class extend it and then render off of the two variables. Like so:

public void draw(Graphics2D g2d) {
    g2d.drawImage(getPlayerImg(), posX, posY, null);
    if (showBounds == true) {
        g2d.draw(getBounds());
    }
}

I need to access these variables like this (This is in my enemy class):

public static void moveFemale(){
    if(posX <= Player.posX){
        //do AI code
    }
}

posX And Player.posX throw an error saying I need to change the modifier of posX in Entity.java to static. But when I change it to static, my renderer for the enemy class stops working and the enemies no longer show up on screen. How could I go about creating a variable that allowed me to do this:

public static void moveFemale(){
    if(posX <= Player.posX){
        //do AI code
    }
}

And still render my enemies? Sorry for the wall of text and any answers would help a lot!

I'd recommend you to read about the keyword `static` and decide if you really need to have your methods declared as `static`. — Andrew Logvinov, Oct 28 '12 at 15:53
I'm guessing this is what you're looking for: http://stackoverflow.com/questions/6320190/java-extended-static-class-of-a-non-static-class — Nano, Oct 28 '12 at 16:38

score 2 · Accepted Answer · answered Oct 28 '12 at 15:53

2

The moveFemale method is static so it needs to know which female to move. Either pass in a reference to the palyer or find a may to make the move methods non-static member methods of the player.

answered Oct 28 '12 at 15:53

Andrew White

52,720
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score 0 · Answer 2 · answered Oct 28 '12 at 15:53

0

I think, you should remove modifier static from method moveFemale

 public void moveFemale(){
    if(posX <= Player.posX){
        //do AI code
    }
  }

answered Oct 28 '12 at 15:53

yatul

1,103
12
27

Player.posX should not be accessed in a static way since it's not static. – Andrew White Oct 28 '12 at 15:54
1

Andrew suggest good thing to pass player as param to this method. Than you will be able to get player's position from it. – yatul Oct 28 '12 at 15:58
2

@opiop65: What do you mean by "wants to be"? How much do you understand about what `static` means? – Jon Skeet Oct 28 '12 at 15:58

Static variable messing everything up

2 Answers2