Game Error (NullPointerException)

Processing Coding Questions
1

I’m currently trying to create a game for my computer science class and I’m having a bit of a rocky start, to be honest. What I have below is the basis of the game but I’m running into a problem when I run the code. It displays an error saying “NUllPointerException” and then highlights this line of code: “image(standingImages[int(frame)], link[0], link[1]);” I’m hoping to not change any of the code to new things I haven’t done before, as I’m a beginner and I can’t show my teacher code that has things we’ve never done before. If anyone would be willing to help, it would be greatly appreciated! thank you! (See Code Below)

PImage[] rightImages=new PImage[6];

PImage[] leftImages=new PImage[6];

PImage[] standingImages=new PImage[6];//*********************

Float frame=0.0;

//x   y   for link

int[] link={80, 110};

boolean[] keys=new boolean[128];

boolean moveRight=false;

boolean moveLeft=false;

boolean stand=false;//*********************

void setup() {

  size(300, 300);

  frameRate(60);

  //loading all "standing" images

  for (int i=1; i<standingImages.length; i++) {//***************************

    standingImages[i]=loadImage("link stand "+(i)+".png");

  }

  //loading all "right" images

  for (int i=1; i<rightImages.length; i++) {

    rightImages[i]=loadImage("linkright"+(i)+".png");

  }

  //loading all "left" images

  for (int i=1; i<leftImages.length; i++) {

    leftImages[i]=loadImage("linkleft"+(i)+".png");

  }

}//end setup

void draw() {

  background(200, 80, 50);

  moveLink();

  if (moveRight) {

    image(rightImages[int(frame)], link[0], link[1]);

  } 

  else if (moveLeft) {

    image(leftImages[int(frame)], link[0], link[1]);

  }

  else if (stand) {//******************************************

    image(standingImages[int(frame)], link[0], link[1]);

  }

  frame+=0.1;

  if (frame>6) {

    frame=1.0;

  }

}//end draw

void moveLink() {

  if (keys[65]) {//65 is 'a' - move left

    link[0]-=3;

    moveLeft=true;

  } else{

    moveLeft=false;

  }

  if (keys[68]) {//68 is 'd' - move right

    link[0]+=3;

    moveRight=true;

  } else {

    moveRight=false;

  }

  if (keys[65]==false && keys[68]==false){//******************************

      stand=true;

  }

}//end moveLink

void keyPressed() {

  keys[keyCode]=true;

}

void keyReleased() {

  keys[keyCode]=false;

}
1 Like
2

are you sure you haven’t added an extra space in this line

standingImages[i]=loadImage("link stand "+(i)+".png");

shouldn’t it be

standingImages[i]=loadImage("link stand"+(i)+".png");
3

I tried that out but it still comes up with NullPointerException on the same line unfortunately

4

in this part of the code where you load the images you skip loading an image into the first array index.

for (int i=1; i<standingImages.length; i++) {
    standingImages[i]=loadImage("link stand"+(i)+".png");
}

you can change this to

for (int i=1; i<standingImages.length; i++) {
    standingImages[i - 1]=loadImage("link stand"+(i)+".png");
}

edit: also your frame count should probably go from 0-5 not 1-6

and as int acts as a floor when you call it on the frame as an index into the image array you can leave those but just change this as well

  if (frame>6) {
    frame=1.0;
  }

to

  if (frame>6) {
    frame=0;
  }
1 Like
5

Now it seems to be running the standing animation for a few frames and then returns with NullPointerException still. Sorry if it seems like I’m being needy I’m just stumped lol. I really appreciate the help!

6

i would check your file names. or check against this version which just has the adjustments i made with just some images which show the frame number etc.

7

Thank you a lot! I’ll keep working at it : )