CODEWITHSUNDEEP
androidloopsarraylistlibgdxindexoutofboundsexception
user3091110
user3091110

Reputation: 81

Trouble running my code: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

can someone help me out with this problem. this is the error message I get:

Exception in thread "LWJGL Application" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
    at java.util.ArrayList.rangeCheck(ArrayList.java:635)
    at java.util.ArrayList.get(ArrayList.java:411)
    at com.mygdx.Papermadness.Papermadness.render(Papermadness.java:102)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:206)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114)

This is the code of my for loop through the huisArray (huis= house).

private ArrayList<Sprite> huisArray = new ArrayList<Sprite>();

spriteBatch.begin();

    sprite.draw(spriteBatch);



     for (int i = 0; i < huisArray.size(); i++) {
            huisArray.get(i).setY(huisArray.get(i).getY() - huisVelocity * delta);

                 if (huisArray.get(i).getY() <= 200) {
                huisArray.remove(huisArray.get(i));
            } 

        }


      if (huisArray.get(0).getY() < 1200) {
            addNewHuis();
        }

     huisBatch.begin();

     for (int i = 0; i < huisArray.size(); i++) {
            huisArray.get(i).setY(huisArray.get(i).getY() - huisVelocity * delta);

                 if (huisArray.get(i).getY() <= 200) {
                huisArray.remove(huisArray.get(i));
            } 

        }


      if (huisArray.get(0).getY() < 1200) {
            addNewHuis();
        }

     huisBatch.begin();


      for (int i = 0; i < huisArray.size(); i++) {
            huisBatch.draw(huisArray.get(i), huisArray.get(i).getX(), huisArray.get(i).getY());
        }
spriteBatch.end();
    huisBatch.end();

The idea of this code is that houses at the two edges of the screen fall continuesly.

Any help would be appreciated :)

Upvotes: 0

Views: 1405

Answers (3)

JML
JML

Reputation: 721

Here:

if (huisArray.get(0).getY() < 1200) {
        addNewHuis();
    }

You're accessing to the first element in the huisArray, but never checking if it's empty.

Add a size check before:

if (huisArray.size > 0 &&huisArray.get(0).getY() < 1200) {
        addNewHuis();
    }

There's also another problem in your for loops:

for (int i = 0; i < huisArray.size(); i++) {
        huisArray.get(i).setY(huisArray.get(i).getY() - huisVelocity * delta);

             if (huisArray.get(i).getY() <= 200) {
            huisArray.remove(huisArray.get(i));
        } 

    }

If you remove things inside the for loop just like that, you'll be ignoring some items:

Let's say you're array have 3 elements [A, B, C], and the first one have the conditions to be removed.

So in the first loop, you'll have:

i = 0 array = [A, B, C]

A is removed, and the second loop starts

i = 1 array = [B, C]

See that now you'll check for C (which is in position 1), and you'll never check B

To avoid this (using that kind of for loop) just add:

for (int i = 0; i < huisArray.size(); i++) {
        huisArray.get(i).setY(huisArray.get(i).getY() - huisVelocity * delta);

             if (huisArray.get(i).getY() <= 200) {
            huisArray.remove(huisArray.get(i));
            i--;
        } 

    }

Also as an advice, if you know the position of the item you wan't to remove, remove it by index instead of removing by object (it's faster)

huisArray.remove(i);

Upvotes: 0

Giru Bhai
Giru Bhai

Reputation: 14408

The problem is that huisArray is empty and you are getting values from this list at line

  if (huisArray.get(0).getY() < 1200) {

So first add items in huisArray before checking item in huisArray as

private ArrayList<Sprite> huisArray = new ArrayList<Sprite>();
// Add huisArray item here as huisArray.add(addspritehere);

Or change 

  if (huisArray.get(0).getY() < 1200) {

to

if (huisArray.size() > 0 && huisArray.get(0).getY() < 1200) {

Upvotes: 1

Andrew Schuster
Andrew Schuster

Reputation: 3229

Your error is likely right here:

if (huisArray.get(0).getY() < 1200) {

If your huisArray has a size of zero, then getting an object out of it will throw an exception. You should check if it has anything in it first, as follows

if (huisArray.size() > 0 && huisArray.get(0).getY() < 1200) {

Upvotes: 1

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