How to make multiple enemies affect health

Heres my new code:

//Declared Global Variables
final static float MOVE_SPEED = 7.5;
final static float SPRITE_SCALE = 50.0/64;
final static float SPRITE_SCALE1 = 50.0/1920;
final static float SPRITE_SCALE2 =50.0/45;
final static float SPRITE_SCALE3 = 225.0/600;
final static float Teach_Scale=100.0/2800;
final static float SPRITE_SIZE = 50;
final static float GRAVITY= 0.6;
final static float JUMP_SPEED = 17.5;

final static float RIGHT_MARGIN = 400;
final static float LEFT_MARGIN = 60;
final static float VERTICAL_MARGIN = 40;

final static int NEUTRAL_FACING = 0;
final static int RIGHT_FACING = 1;
final static int LEFT_FACING = 2;

final static float WIDTH = SPRITE_SIZE * 38.4;
final static float HEIGHT = SPRITE_SIZE * 24;
final static float GROUND_LEVEL = HEIGHT-SPRITE_SIZE;

int sec = second();
Sprite teach;
Sprite s1,s2;
Player p;
Sprite text;
PImage tile1, desk, enemy, shelf, p1;
float view_x = 0;
float view_y =0;
ArrayList platforms;
ArrayList walks;
Enemy enemi;
Enemy enemi1;
Enemy enemi2;
Enemy enemi3;
Enemy enemi4;
//initialize variables
int green1, green2, green3, green4, green5,green6,green7,green8,green9,green10;
int bar_of_know;
boolean isGameOver;
boolean chat=false;
boolean chat1=false;
boolean chat2=false;
boolean chat3=false;
boolean chat4=false;
boolean chat5=false;
boolean firstDone=false;
boolean secondDone=false;
boolean thirdDone=false;
boolean fourthDone=false;
boolean fifthDone=false;
boolean sixthDone=false;
boolean reset=false;
boolean reset1=false;
boolean reset2=false;
boolean reset3=false;
boolean reset4=false;
boolean firstRun=true;
void setup(){
size(1920,1200);
imageMode(CENTER);
p1 = loadImage(“walk1.png”);
teach = new Sprite(“teach.png”, Teach_Scale, 3200,850);
p=new Player(p1, 1.0);
bar_of_know=0;
p.setBottom(400);
p.center_x= 100;
p.change_x=0;
p.change_y=0;
isGameOver=false;
platforms = new ArrayList();
walks = new ArrayList();
enemy = loadImage(“enemywalk.png”);
tile1=loadImage(“Tile1.png”);
desk=loadImage(“Desk.png”);
shelf = loadImage(“shelf1.png”);
createPlatforms(“map1.csv”);
green1 = 0;
green2 =0;
green3=0;
green4=0;
green5=0;
green6=0;
green7=0;
green8=0;
green9=0;
green10=0;
}

//modify and draw images
void draw(){
background(255);
scroll();

displayAll();
//if(!isGameOver){
updateAll();
//}
}

void scroll(){
float right_boundary = view_x+width-RIGHT_MARGIN;
if(p.getRight()> right_boundary){
view_x+=p.getRight()-right_boundary;
}
float left_boundary = view_x+LEFT_MARGIN;
if(p.getLeft()<left_boundary){
view_x -=left_boundary-p.getLeft();
}
float bottom_bound = view_y+height-VERTICAL_MARGIN;
if(p.getBottom()>bottom_bound){
view_y+=p.getBottom()-bottom_bound;
}
float top_bound = view_y+VERTICAL_MARGIN;
if(p.getTop()<top_bound){
view_y -= top_bound-p.getTop();
}
translate(-view_x,-view_y);
}

void drawRect(){
fill(174, green1, 255);
rect(view_x, view_y, 100, 50);
fill(174,green2, 255);
rect(view_x+101, view_y, 100, 50);
fill(174,green3, 255);
rect(view_x+202, view_y, 100, 50);
fill(174,green4, 255);
rect(view_x+303, view_y, 100, 50);
fill(174,green5, 255);
rect(view_x+404, view_y, 100, 50);
fill(174,green6, 255);
rect(view_x+505, view_y, 100, 50);
fill(174,green7, 255);
rect(view_x+606, view_y, 100, 50);
fill(174,green8, 255);
rect(view_x+707, view_y, 100, 50);
fill(174,green9, 255);
rect(view_x+808, view_y, 100, 50);
fill(174,green10, 255);
rect(view_x+909, view_y, 100, 50);
}

public boolean isOnPlat(Sprite s, ArrayList walls){
s.center_y+=5;
ArrayListcol_list =checkCollisionList(s, walls);
s.center_y-=5;
if(col_list.size()>0){
return true;
}
else {
return false;
}
}

public boolean checkCollision(Sprite s1, Sprite s2){
boolean noXOverlap = s1.getRight() <= s2.getLeft() || s1.getLeft()>=s2.getRight();
boolean noYOverlap = s1.getBottom() <= s2.getTop() || s1.getTop()>=s2.getBottom();
if (noXOverlap || noYOverlap){
return false;
}
else {
return true;
}
}

ArrayList checkCollisionList(Sprite s1, ArrayList list){
ArrayList collision_list = new ArrayList();
for(Sprite p: list){
if(checkCollision(s1, p))
collision_list.add(p);
}
return collision_list;
}

public void resolvePlatformCollisions(Sprite s, ArrayList walls){
s.change_y +=GRAVITY;
s.center_y += s.change_y;
ArrayList col_list = checkCollisionList(s,walls);
if(col_list.size()>0){
Sprite collided = col_list.get(0);
if(s.change_y>0){
s.setBottom(collided.getTop());
}
else if(s.change_y<0){
s.setTop(collided.getBottom());
}
s.change_y=0;
}

s.center_x+=s.change_x;
col_list = checkCollisionList(s,walls);
if(col_list.size()>0){
Sprite collided = col_list.get(0);
if(s.change_x>0){
s.setRight(collided.getLeft());
}
else if(s.change_x<0){
s.setLeft(collided.getRight());
}
}

}

void createPlatforms(String filename){
String lines = loadStrings(filename);
for (int row=0; row < lines.length; row++){
String values = split(lines[row], “,”);
for(int col = 0; col<values.length; col++){
if(values[col].equals(“1”)){
Sprite t= new Sprite(tile1, SPRITE_SCALE);
t.center_x = SPRITE_SIZE/2+colSPRITE_SIZE;
t.center_y=SPRITE_SIZE/2+row
SPRITE_SIZE;
platforms.add(t);
}
else if (values[col].equals(“2”)){
Sprite s = new Sprite(desk, SPRITE_SCALE1);
s.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
s.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
platforms.add(s);
}
else if (values[col].equals(“3”)){
Sprite s = new Sprite(shelf, SPRITE_SCALE3);
s.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
s.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
platforms.add(s);
}
else if (values[col].equals(“4”)){
float bLeft = colSPRITE_SIZE;
float bRight = bLeft + 8 * SPRITE_SIZE;
enemi = new Enemy(enemy, 50.0/32, bLeft, bRight);
enemi.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
enemi.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
walks.add(enemi);
}
else if (values[col].equals(“5”)){
float bLeft = col
SPRITE_SIZE;
float bRight = bLeft + 7 * SPRITE_SIZE;
enemi = new Enemy(enemy, 50.0/32, bLeft, bRight);
enemi.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
enemi.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
walks.add(enemi);
}
else if (values[col].equals(“6”)){
float bLeft = colSPRITE_SIZE;
float bRight = bLeft + 6 * SPRITE_SIZE;
enemi = new Enemy(enemy, 50.0/32, bLeft, bRight);
enemi.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
enemi.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
walks.add(enemi);
}
else if (values[col].equals(“7”)){
float bLeft = col
SPRITE_SIZE;
float bRight = bLeft + 5 * SPRITE_SIZE;
enemi = new Enemy(enemy, 50.0/32, bLeft, bRight);
enemi.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
enemi.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
walks.add(enemi);
}
else if (values[col].equals(“8”)){
float bLeft = col*SPRITE_SIZE;
float bRight = bLeft + 4 * SPRITE_SIZE;
enemi = new Enemy(enemy, 50.0/32, bLeft, bRight);
enemi.center_x = SPRITE_SIZE/2 + col * SPRITE_SIZE;
enemi.center_y = SPRITE_SIZE/2 + row * SPRITE_SIZE;
walks.add(enemi);
}
}
}
}

//call whenever a key is pressed
void keyPressed(){
if(keyCode == RIGHT){
p.change_x=MOVE_SPEED;
}
else if(keyCode == LEFT){
p.change_x=-MOVE_SPEED;
}
else if(keyCode == UP && isOnPlat(p, platforms)){
p.change_y= -JUMP_SPEED;
}
else if(isGameOver && key == ’ '){
setup();
}
if(checkCollision(p,teach) && key ==‘f’ && firstRun==true){
chat=true;
}
if(checkCollision(p,teach) && key==‘f’&&reset==true){
chat1=true;
}
else if(checkCollision(p,teach) && key==‘f’ &&reset1==true){
chat2=true;
}
else if(checkCollision(p,teach) && key==‘f’ &&reset2==true){
chat3=true;
}
else if(checkCollision(p,teach) && key==‘f’ &&reset3==true){
chat4=true;
}
else if(checkCollision(p,teach) && key==‘f’ &&reset4==true){
chat5=true;
}
if(key==‘r’){
p.center_x=100;
p.setBottom(800);
reset=true;
firstRun=false;
}
if(key==‘r’ && bar_of_know==4){
p.center_x=100;
p.setBottom(800);
reset1=true;
reset=false;
reset2=false;
reset3=false;
reset4=false;
}
if(key==‘r’ && bar_of_know==6){
p.center_x=100;
p.setBottom(800);
reset2=true;
reset1=false;
reset=false;
reset3=false;
reset4=false;
}
if(key==‘r’ && bar_of_know==8){
p.center_x=100;
p.setBottom(800);
reset3=true;
reset=false;
reset2=false;
reset1=false;
reset4=false;
}
if(key==‘r’ && bar_of_know==10){
p.center_x=100;
p.setBottom(800);
reset4=true;
reset=false;
reset2=false;
reset3=false;
reset1=false;
}

if(key == ESC){
exit();
}
}

//call whenever a key is released
void keyReleased(){
if(keyCode == RIGHT){
p.change_x=0;
}
else if(keyCode == LEFT){
p.change_x=0;
}
else if(keyCode == UP){
p.change_y=0;
}
else if(keyCode == DOWN){
p.change_y=0;
}
else if(key==‘f’){
chat=false;
chat1=false;
chat2=false;
chat3=false;
chat4=false;
chat5=false;
}
else if(key==‘r’){

}
}

void displayAll(){
for(Sprite s: platforms){
s.display();
}
for(Sprite enemi: walks){
enemi.display();
}
p.display();
textSize(32);
text("Bar Of Knowledge: "+bar_of_know,view_x+50,view_y+100);
drawRect();
teach.display();
//textSize(32);
//text(“reset:”+reset,view_x+50,view_y+200);
//text(“reset1:”+reset1,view_x+50,view_y+300);
//text(“reset2:”+reset2,view_x+50,view_y+400);
//text(“reset3:”+reset3,view_x+50,view_y+500);
//text(“reset4:”+reset4,view_x+50,view_y+600);
if(chat){
textSize(32);
text(“Master the basics of supply and demand,”, 2500,650);
text(“and connect economic concepts to current”,2500,700);
text(“events for a practical understanding of”,2500,750);
text(“how economics influences the world around you.”,2500,800);
firstDone=true;
}

if(chat1){
text(“Master social science basics like culture”, 2500,650);
text(“and human behavior, and connect them”,2500,700);
text(“to current events for a practical”,2500,750);
text(“understanding of the world’s complexities.”,2500,800);
secondDone=true;
}
if(chat2){//CHANGE
text(“Master social science basics like culture”, 2500,650);
text(“and human behavior, and connect them”,2500,700);
text(“to current events for a practical”,2500,750);
text(“understanding of the world’s complexities.”,2500,800);
thirdDone=true;
}
if(chat3){//CHANGE
text(“Master social science basics like culture”, 2500,650);
text(“and human behavior, and connect them”,2500,700);
text(“to current events for a practical”,2500,750);
text(“understanding of the world’s complexities.”,2500,800);
fourthDone=true;
}
if(chat4){//CHANGE
text(“Master social science basics like culture”, 2500,650);
text(“and human behavior, and connect them”,2500,700);
text(“to current events for a practical”,2500,750);
text(“understanding of the world’s complexities.”,2500,800);
fifthDone=true;
}
if(chat5){//CHANGE
text(“Master social science basics like culture”, 2500,650);
text(“and human behavior, and connect them”,2500,700);
text(“to current events for a practical”,2500,750);
text(“understanding of the world’s complexities.”,2500,800);
sixthDone=true;
}
if(firstDone==true){
bar_of_know=2;
firstDone=false;
}
else if(secondDone==true){
bar_of_know=4;
secondDone=false;
}
else if(thirdDone==true){
bar_of_know=6;
thirdDone=false;
}
else if(fourthDone==true){
bar_of_know=8;
fourthDone=false;
}
else if(fifthDone==true){
bar_of_know=10;
fifthDone=false;
}

collectKnowledge();
if(isGameOver){
if(bar_of_know==-100){
text(“YOU LOSE”,view_x+500,view_y+500);
}
else{
text(“YOU WIN”,view_x+500,view_y+500);
}}}

void updateAll(){
checkDeath();
if(bar_of_know==1){
green1=198;
}
else if(bar_of_know==2){
green1=198;
green2=198;
}
else if(bar_of_know==4){
green1=198;
green2=198;
green3=198;
green4=198;
}
else if(bar_of_know==6){
green1=198;
green2=198;
green3=198;
green4=198;
green5=198;
green6=198;
}
else if(bar_of_know==8){
green1=198;
green2=198;
green3=198;
green4=198;
green5=198;
green6=198;
green7=198;
green8=198;
}
else if(bar_of_know==10){
green1=198;
green2=198;
green3=198;
green4=198;
green5=198;
green6=198;
green7=198;
green8=198;
green9=198;
green10=198;
}
else{
green1=0;
green2=0;
green3=0;
green4=0;
green5=0;
green6=0;
green7=0;
green8=0;
green9=0;
green10=0;
}
for(Sprite enemi:walks){
enemi.update();
((AnimatedSprite)enemi).updateAnimation();
}
p.updateAnimation();
resolvePlatformCollisions(p,platforms);
}

void checkDeath(){
boolean collideEnemy = checkCollision(p, enemi);

 if(collideEnemy){
  bar_of_know--;
  if(bar_of_know==-100){
   isGameOver=true; 
  }
 }

}

void collectKnowledge(){
if(bar_of_know==10){
isGameOver=true;
}
}