[LibGDX] NullPointerException and batch

Engines, Libraries and Tools
#1

Hi ;D

I’m trying to make a simple tile mapping but I have a problem with the rendering. I have a NullPointer exception :frowning:


Caused by: java.lang.NullPointerException
	at Map.render(Map.java:51)
	at .render(LabC.java:47)

I use 3 classes :

  • Block => Each Tile
  • Map => two dimensional “Block” array
  • LabC => The main class

For rendering one Block I use this function:

Block.java:

public void render(){
// "sprite" is a Sprite object for Texture, position ... of the Tile.
		sprite.draw(LabC.batch);
	}

To display all tiles I use this function:
Map.java

public void render(){
		for(int y = 0;y < map.length; y++){
			for(int x =0;x < map[1].length; x++){
				blockmap[x][y].render();
			}
		}
	}

And the render method :

LaboC.java

public static SpriteBatch batch;
...
public void render() {		
		Gdx.gl.glClearColor(0, 0, 0, 1);
		Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
		batch.setProjectionMatrix(camera.combined);
		
		batch.begin();
		test.render();
//"test" is a Map object
		batch.end();
	}

Thx for the help

#2

it must be an initialization problem, make sure you initialize all your variable before using them .
good luck

#3 
public void render(){
// "sprite" is a Sprite object for Texture, position ... of the Tile.
      LabC.batch.begin();
      sprite.draw(LabC.batch);
      LabC.batch.end();
   }

That’s your solution, I’m pretty sure. I’m not too keen on your use of statics for this, but I think that should work.

#4

Make sure you initialize everything in the create() method instead of statically in the class “header”.

#5

Full code of LabC class.

#6

Would passing an instance of Map (or maybe just blockmap[][]) to LaboC so it could be rendered there be a better solution (given of course that it makes sense considering the TS’s code overall)?

#7

I fix my problem !
Appently my inititalization wasn’t good
Thx for the help