Hello
I'm trying to program a game but i get this error massage:
java.lang.NullPointerException
at Guard.<init>(Guard.java:23)
Can somebody help me?
I have a world (Level01), Hero class and few other Actor class (Guard,Heart...etc). I would like to change the variables of Hero from other Actors.
Level01:
Hero:
Guard:
public class Level01 extends World
{
public Hero goblin = new Hero();
public TopDisplay TD;
public BottomDisplay BD = new BottomDisplay();
public Level01()
{
super(800, 600, 1);
TD = new TopDisplay();
addObject(goblin,100,100);
addObject(TD,getWidth()/2,20);
addObject(BD,getWidth()/2,getHeight()-20);
for (int i=0; i<6; i++)
{
addObject(new Barrel(), Greenfoot.getRandomNumber(750)+50, Greenfoot.getRandomNumber(300)+60);
addObject(new Wall(), Greenfoot.getRandomNumber(750)+50, Greenfoot.getRandomNumber(300)+60);
addObject(new Heart(), Greenfoot.getRandomNumber(800), Greenfoot.getRandomNumber(300)+50);
}
}
public Hero getHero()
{
return goblin;
}
}public class Hero extends Actor
{
//Variable of hero's properties
int maxHP=100;
int HP=100;
int maxArmor=100;
int armor=50;
public void changeHeroHP(int dHP)
{
if (HP+dHP>maxHP) HP=maxHP;
else if ((HP+dHP)<1) {HP=0; gameOver();}
else HP=HP+dHP;
}
public void gameOver()
{
Greenfoot.stop();
}
}public class Guard extends Enemies
{
Level01 w;
Hero goblin;
int speed=2;
/**
*
* the 'Act' or 'Run' button gets pressed in the environment.
*/
public Guard()
{
w=(Level01) getWorld();
//goblin = (Hero) w.getObjects(Hero.class).get(0);
goblin = w.getHero();
}
public void act()
{
int x=getX();
int y=getY();
int gx=goblin.getX();
int gy=goblin.getY();
if (Math.abs(gx-x)>Math.abs(gy-y)){setLocation(x+speed*(Math.abs(gx-x)/(gx-x)),y);}
else {setLocation(x,y+speed*(Math.abs(gy-y)/(gy-y)));}
if (isTouching(Hero.class)) {goblin.changeHeroHP(-30);getWorld().removeObject(this);}
}
}