CODEWITHSUNDEEP
javanon-staticstatic
juliand665
juliand665

Reputation: 35

Why can't I call a non-static variable?

Eclipse says I can't make a static reference to the non-static field Art.instance. Why does it think I'm calling Art.instance from a static context?

TDRenderer itself gets called like so:

renderer = new TDRenderer();

TDRenderer.java:

package towerDefense;

import java.awt.Graphics;
import java.awt.Image;

public class TDRenderer {

    public Art art;

    public TDRenderer()
    {
        art = Art.instance;
    }

    public void render(Graphics g)
    {
        for(int i = 0; i < 32; i++)
        {
            for(int j = 0; j < 24; j++)
            {
                Image itd = (Image)(art.sprites[art.level1.tiles[i][j].type]);
                g.drawImage(itd, itd.getWidth(null), itd.getHeight(null), null);
            }
        }
    }
}

Upvotes: 0

Views: 520

Answers (3)

ring bearer
ring bearer

Reputation: 20783

    public class TDRenderer {   
     public Art art;

        public TDRenderer()
        {
            art = Art.instance;
        }
//so on..

Assumption 1 - Art.instance is a static instance.

If so, you should declare your local variable art of TDRenderer as public static Art art;

Well then it is redundant and useless. Why don't you directly refer to Art.instance wherever you need it?

Upvotes: 0

JKomusin
JKomusin

Reputation: 364

You're calling the instance property on the Art class.

If it's not static (i.e. a class variable), then there is no value, as it is expecting to be referenced inside an object instantiated from the Art class.

If you want a single value reference-able from anywhere Art is imported, then put the static prefix in front of the instance declaration and provide a value for it in the Art file. If you're looking to access the instance variable from a specific Art object, you need to create one and reference the instance property of the created object.

Upvotes: 0

Louis Wasserman
Louis Wasserman

Reputation: 198043

It's not that you're in a static context; it's that instance is not a static field of Art, but referencing it as Art.instance means you're trying to use it as if it were static.

Upvotes: 4

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