Slick2D正在加载图像无法正常工作

Question

So I'm trying to load an image using Slick2D but for some reason I get the following error when I attempt to draw the image to the screen:

Sat Sep 28 16:37:59 NZST 2013 ERROR:null
java.lang.NullPointerException
    at org.newdawn.slick.Graphics.drawImage(Graphics.java:1350)
    at org.newdawn.slick.Graphics.drawImage(Graphics.java:1399)
    at Game.render(Game.java:58)
    at org.newdawn.slick.GameContainer.updateAndRender(GameContainer.java:703)
    at org.newdawn.slick.AppGameContainer.gameLoop(AppGameContainer.java:456)
    at org.newdawn.slick.AppGameContainer.start(AppGameContainer.java:361)
    at Game.main(Game.java:42)
Sat Sep 28 16:37:59 NZST 2013 ERROR:Game.render() failure - check the game code.
org.newdawn.slick.SlickException: Game.render() failure - check the game code.
    at org.newdawn.slick.GameContainer.updateAndRender(GameContainer.java:706)
    at org.newdawn.slick.AppGameContainer.gameLoop(AppGameContainer.java:456)
    at org.newdawn.slick.AppGameContainer.start(AppGameContainer.java:361)
    at Game.main(Game.java:42)

I am using this to load my image:

import org.newdawn.slick.Image;
import org.newdawn.slick.SlickException;

public class Textures {

    static Image grass;
    Game game;


    public Textures() {
            try {
                grass = new Image("grass.jpg");
            } catch (SlickException e) {
                e.printStackTrace();
            }
    }

}

I am using this to draw my image:

for(int x = 0; x < app.getWidth(); x+=32) {
    for(int y = 0; y < app.getHeight(); y+=32) {
        g.drawImage(textures.grass, x, y);
    }
}

Answer 1

If you get a NullPointerException when trying to draw an Image , it's usually because the image loader didn't find the image at the location specified. If you're using Eclipse , be sure to store your images in a source folder (for instance named "resources"). This ensures images are moved to the bin folder on compilation (may require refreshing the source folder).

Regardless of your setup, be sure the path to the image is correct.