Slick2D How to add a method from a diffrent class to a method

Question

I am trying to get keyboard input in a separate class so everything doesn't look as messy. I get the following error message

Exception in thread "main" java.lang.NullPointerException
    at com.****.****.Menu.init(Menu.java:33)
    at com.****.****.Main.initStatesList(Main.java:35)
    at org.newdawn.slick.state.StateBasedGame.init(StateBasedGame.java:164)
    at org.newdawn.slick.AppGameContainer.setup(AppGameContainer.java:393)
    at org.newdawn.slick.AppGameContainer.start(AppGameContainer.java:317)
    at com.****.****.Main.main(Main.java:27)

This is what I tried:

Menu Class where I load the methods

public class Menu extends BasicGameState{

KeyboardInput kbi;

public Menu(int state) {

}

@Override
public void init(GameContainer gc, StateBasedGame sbg) throws SlickException {

    kbi.init();

}

@Override
public void render(GameContainer gc, StateBasedGame sbg, Graphics g) throws SlickException {    
    kbi.render();
}

@Override
public void update(GameContainer gc, StateBasedGame sbg, int delta) throws SlickException {
    kbi.update();
}

@Override
public int getID() {

    return 0;
}

} 

KeyboardInput class

public class KeyboardInput {

public KeyboardInput() {

}

public void init() {    

}

public void render() {

}

public void update() {

}
}

Answer 1

You need to create an instance of your keyboard class.

Change your menu constructor to this:

public Menu(int state) {
    kbi = new KeyboardInput();
}