Populating an object array in Processing - All objects are the same - processing

Question

I assure you I have spent hours trying to find a solution on the internet to this already, but I am in dire need of a fresh pair of eyes. I am using ArrayLists at the moment but have tried using a normal object array and the same problem occurred. For context I am trying to simulate an epidemic and am attempting to populate an array of the type "Person" with random positions within the boundaries of a community. The Person class at the moment is as follows:
private PVector pos;
class Person{
public Person(float x, float y){
pos = new PVector(x, y);
}
void show(){
ellipse(pos.x, pos.y, 10, 10);
}
float xPos(){
return pos.x;
}
}
My Community class is as follows:
private float size;
private PVector origin;
private ArrayList<Person> personArr;
class Community{
public Community(float x, float y, float size_){
origin = new PVector(x, y);
size = size_;
personArr = new ArrayList<Person>();
}
void show(){
noFill();
rect(origin.x, origin.y, size, size);
showPersons();
}
void setupCommunity(){
for(int i = 0; i < initialPopulation; i++){
float x1 = random(origin.x, origin.x + size);
float y1 = random(origin.y, origin.y + size);
Person person = new Person(x1, y1);
personArr.add(person);
}
}
void showPersons(){
for(int i = 0; i < personArr.size(); i++){
personArr.get(i).show();
}
}
}
The show() method for the community is called once every frame in the draw() method in my main Simulation class, which for reference sake, looks like this so far:
Grapher graphInfected, graphSuseptible, graphRemoved;
Community community;
float graphLength = 250;
float communitySize;
int initialPopulation = 25, population;
int populationInfected = 2, populationSusceptible = 23, populationRemoved = 0;
public void settings(){
size(1700, 1000);
communitySize = height * 0.8;
}
void setup(){
population = initialPopulation;
community = new Community(150, 100, communitySize);
community.setupCommunity();
graphInfected = new Grapher(width/2 + 240 + 200, height/2 - 230, "Infected", graphLength);
graphSuseptible = new Grapher(width/2 + 240 + 200, height/2 + 90, "Suseptible", graphLength);
graphRemoved = new Grapher(width/2 + 240 + 200, height/2 + 400, "Removed", graphLength);
}
void draw(){
background(255);
community.show();
graphInfected.addToArray(populationInfected);
graphSuseptible.addToArray(populationSusceptible);
graphRemoved.addToArray(populationRemoved);
graphInfected.show();
graphSuseptible.show();
graphRemoved.show();
}
The idea is to display all the people in the Persons array within the community rectangle, which is happening, it just looks like 1 person because they are all being drawn at the same position. I know this because upon debugging, I saw that while adding to the personArr in the community setup, the random positions were different, but each time I added to the array list, the entire list was populated with the exact same Person. This resulted in the whole list consisting of the last person that was created. I would appreciate it if someone knew why! I just need the list to be populated with the individual Person objects! Thank you <3
In case you want to try and run the project, here is the code for the grapher:
class Grapher {
private IntList population;
private int countArr = 1, dataLength = 0;
private PVector[] linePos;
private PVector origin;
private String graphType = "";
private float length;
private String yLable = "";
Grapher(int x, int y, String graphType, float length){
origin = new PVector(x, y);
population = new IntList();
this.graphType = graphType;
this.length = length;
population.set(0, initialPopulation);
}
//Called every every frame
void show() {
dataLength = population.size();
linePos = new PVector[dataLength];
//background(255, 255, 255);
int largestPop = initialPopulation;
for (int i = 0; i < dataLength; i++) {
if (population.get(i) > largestPop) {
largestPop = population.get(i);
}
}
//UI code
stroke(0, 0, 0);
line(origin.x, origin.y, origin.x + (int) length, origin.y);
fill(0);
textSize(15);
text("" + largestPop, origin.x - 60, origin.y - length);
text("" + dataLength, origin.x + length, origin.y + 25);
fill(0);
textSize(15);
text("Time", (float) (origin.x + length/2 - length/10), origin.y + 30);
text(yLable, origin.x - 100, (float) (origin.y - length/2));
//Calculating the graph points
line(origin.x, origin.y, origin.x, origin.y - (int) length);
double yInterval = length/(largestPop);
double interval = length/dataLength;
for (int i = 0; i < dataLength; i++) {
float xPos = origin.x + (float) interval * i;
float yPos = origin.y - ((float) yInterval * (population.get(i)));
linePos[i] = new PVector(xPos, yPos);
//ellipse(xPos, yPos, 5, 5);
}
//Picking the graph colour
if(graphType.equalsIgnoreCase("Infected")){
stroke(255, 0, 0);
yLable = "Infected";
}else if(graphType.equalsIgnoreCase("Susceptible")){
stroke(0, 0, 255);
yLable = "Susceptible";
}else{
stroke(0, 0, 0);
yLable = "Removed";
}
//Drawing the graph and connecting the points
for (int i = 0; i < dataLength - 1; i++) {
line(linePos[i].x, linePos[i].y, linePos[i + 1].x, linePos[i + 1].y);
}
}
void addToArray(int population){
this.population.set(countArr, population);
countArr++;
}
}

Answer 1

PVector pos is placed outside the Person class. So all Person objects use the same pos.
Same thing with the Community class. May cause weird bugs if you create multiple Communities.