NullPointer - TextureRegions

Newbie & Debugging Questions
#1

So, here we have a 96x64 image, composed of 6 32x32 sprites.

Alright, so I have this loading and drawing to the screen (just to make sure it’s not a problem with loading the texture)

So, here’s the line of code throwing the null-pointer

		regions[0][0] = new TextureRegion(playerSheet, 0, 0, 32, 32);

This, from what I understand is supposed to get the first 32x32 pixels starting from 0, 0 in the image, and save it to a TextureRegion.

	private TextureRegion[][] regions;

However, It’s throwing a null and I’m not sure why.

Exception in thread "LWJGL Application" java.lang.NullPointerException
	at com.chris.platformer.entities.Player.loadAssets(Player.java:64)
	at com.chris.platformer.entities.Player.<init>(Player.java:33)
	at com.chris.platformer.screens.GameScreen.show(GameScreen.java:25)
	at com.badlogic.gdx.Game.setScreen(Game.java:62)
	at com.chris.platformer.Game.create(Game.java:10)
	at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:136)
	at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114)

Here’s my loadAssets() method

	private void loadAssets()
	{	
		regions[0][0] = new TextureRegion(playerSheet, 0, 0, 32, 32); 
		regions[1][0] = new TextureRegion(playerSheet, 32, 0, 32, 32); 
		regions[2][0] = new TextureRegion(playerSheet, 64, 0, 32, 32); 
		regions[3][0] = new TextureRegion(playerSheet, 0, 32, 32, 32);	
		regions[4][0] = new TextureRegion(playerSheet, 32, 32, 32, 32);
		regions[5][0] = new TextureRegion(playerSheet, 64, 32, 32, 32);
		
		walkLeft = new Animation(0.40f, regions[0][0], regions[1][0], regions[2][0]);
		walkRight = new Animation(0.40f, regions[3][0], regions[4][0], regions[5][0]);
		
		playerSprite = new Texture("graphics/sprites/player/Player.png");
	}

I believe that should get all 6 of the images, however it can’t even get the first one.

#2

You have 2 possible variables that could be causing the problem

first, either


playerSheet

or


regions[][]

may be null.

Check to see if your playerSheet is null, as I don’t see that anywhere in your snippets you posted

you could use this


if(playerSheet == null){
System.out.println("playerSheet is null");
}

for the array of TextureRegions

make sure you initialize the array


private TextureRegion[][] regions;

public Player(){
regions = new TextureRegion[size][size];
}

edit: renamed the constructor so people don’t have to read the non code snippets.

#3

The exception is not happening inside the TextureRegion constructor so it must be the regions array that is null.
Can you show us how you’re initialising that array?

#4

if you re read it, you will know I never said TextureRegion constructor, but the TextureRegion region[][] is null, I showed him how to initialize the array, because either region[][] or playerSheet is null as they are the only variables that can produce a null pointer, like I said in my post that you only read the code snippets of.

To remove your confusion, I will edit the code and use his class name that he had the exception in.

#5

Phased hit the nail on the head, I happen to forget to initialize arrays frequently and it never registers to me when I recieve the error while trying to set the values