Hello, I have been trying to code a reaction based game for greenfoot which revolves around pressing buttons to create objects, which can be converted into spells. I am trying to calculate how many actors of a particular class there are in the world. I have looked up how to "getObjects" and the how to find their ".size"; however when adding the actor, which calculates all these objects, into the world it gives me :
java.lang.NullPointerException
at Invoker.NumbersE(Invoker.java:89)
at Invoker.<init>(Invoker.java:27)
int QuasNo = 0;
int ExortNo = 0;
int WexNo = 0;
public Invoker()
{
NumbersE();
NumbersQ( );
NumbersW();
invoke();
Cast();
Animation();
}
public void invoke(){
if(Greenfoot.isKeyDown("3")){
if (QuasNo == 3){
}
if(ExortNo == 3){
}
if(WexNo ==3 ){
}
if(QuasNo == 2 && ExortNo == 1){
}
if(QuasNo == 2 && WexNo == 1){
}
if(ExortNo == 2 && WexNo == 1 ){
}
if(ExortNo == 2 && QuasNo == 1 ){
}
if(WexNo == 2 && ExortNo == 1 ){
}
if(WexNo == 2 && QuasNo == 1 ){
}
if(QuasNo == 1 && WexNo ==1 && ExortNo == 1){
}
}
}
public void NumbersE(){
ExortNo = getWorld().getObjects(Exort.class).size();
}
public void NumbersQ(){
QuasNo = getWorld().getObjects(Quas.class).size();
}
public void NumbersW(){
WexNo = getWorld().getObjects(Wex.class).size();
}
