I am trying to make a point counter, and it all compiles but the terminal comes up and says:
These are the three classes. The first is the actor with the variable, the second is the world, and the third is the scoreboard.
Any help is much appreciated! Thank you so much!
java.lang.NullPointerException at Score.<init>(Score.java:16) at World3.<init>(World3.java:25)
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
public class LinkHero extends Dragon
{
public int points = 0;
private int counter = 0;
public void act()
{
move();
get();
}
public void move()
{
if (Greenfoot.isKeyDown("right"))
{
setRotation(0);
move(4);
if (counter <= 2)
{
setImage("LR1.png");
}
else if (counter == 4)
{
setImage("LR2.png");
}
else if (counter == 6)
{
setImage("LR3.png");
}
else if (counter == 8)
{
setImage("LR4.png");
}
else if (counter == 10)
{
setImage("LR5.png");
}
else if (counter == 12)
{
setImage("LR6.png");
}
else if (counter == 14)
{
setImage("LR7.png");
}
else if (counter == 16)
{
setImage("LR8.png");
}
counter++;
if (counter > 16)
{
counter = 0;
}
}
if (Greenfoot.isKeyDown("left"))
{
setRotation(0);
move(-4);
if (counter <= 2)
{
setImage("LL1.png");
}
else if (counter == 4)
{
setImage("LL2.png");
}
else if (counter == 6)
{
setImage("LL3.png");
}
else if (counter == 8)
{
setImage("LL4.png");
}
else if (counter == 10)
{
setImage("LL5.png");
}
else if (counter == 12)
{
setImage("LL6.png");
}
else if (counter == 14)
{
setImage("LL7.png");
}
else if (counter == 16)
{
setImage("LL8.png");
}
counter++;
if (counter > 16)
{
counter = 0;
}
}
if (Greenfoot.isKeyDown("up"))
{
setLocation(getX(), getY() - 4);
if (counter <= 2)
{
setImage("LU1.png");
}
else if (counter == 4)
{
setImage("LU2.png");
}
else if (counter == 6)
{
setImage("LU3.png");
}
else if (counter == 8)
{
setImage("LU4.png");
}
else if (counter == 10)
{
setImage("LU5.png");
}
else if (counter == 12)
{
setImage("LU6.png");
}
else if (counter == 14)
{
setImage("LU7.png");
}
counter++;
if (counter > 14)
{
counter = 0;
}
}
if (Greenfoot.isKeyDown("down"))
{
setLocation(getX(), getY() + 4);
if (counter <= 2)
{
setImage("LD1.png");
}
else if (counter == 4)
{
setImage("LD2.png");
}
else if (counter == 6)
{
setImage("LD3.png");
}
else if (counter == 8)
{
setImage("LD4.png");
}
else if (counter == 10)
{
setImage("LD5.png");
}
else if (counter == 12)
{
setImage("LD6.png");
}
else if (counter == 14)
{
setImage("LD7.png");
}
counter++;
if (counter > 14)
{
counter = 0;
}
}
if (Greenfoot.isKeyDown("enter"))
{
Greenfoot.playSound("win.wav");
Greenfoot.stop();
}
}
public void get()
{
Actor rupee;
rupee = getOneObjectAtOffset(0, 0, Rupee.class);
if (rupee != null)
{
World world = getWorld();
world.removeObject(rupee);
Greenfoot.playSound("rupee.wav");
points++;
}
}
public void Update()
{
;
}
}
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
/**
* Write a description of class World3 here.
*
* @author (your name)
* @version (a version number or a date)
*/
public class World3 extends World
{
public int ScorePoints = 0;
private LinkHero Hero;
private Score score;
/**
* Constructor for objects of class World3.
*
*/
public World3()
{
// Create a new world with 600x400 cells with a cell size of 1x1 pixels.
super(700, 600, 1);
Hero = new LinkHero();
addObject(Hero, 358, 330);
score = new Score();
addObject(score, 691, 576);
prepare();
}
public LinkHero get()
{
return Hero;
}
/**
* Prepare the world for the start of the program. That is: create the initial
* objects and add them to the world.
*/
private void prepare()
{
...(object adding)...
get();
}
}
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.awt.Color;
import java.awt.Font;
/**
* Write a description of class Score here.
*
* @author (your name)
* @version (a version number or a date)
*/
public class Score extends Actor
{
private int score;
public Score()
{
score = ((World3) getWorld()).get().points;
setImage (new GreenfootImage(200, 30));
Update();
}
public void act()
{
Update();
}
public void addScore()
{
score++;
Update();
}
public void Update()
{
GreenfootImage img = getImage();
img.clear();
img.setColor(Color.WHITE);
img.setFont( new Font("Nanum Brush Script", Font.PLAIN, 36));
img.drawString("0" + score, 50, 20);
}
}
