Animation with Texturepacker / LibGDX - render error

Question

I'm trying to produce a simple 18 frame animation using Texturepacker with libGDX (other info: Eclipse, Windows 8).

I'm getting the following LogCat error, coupled with a black screen on my Android test device:

02-20 09:26:15.229: E/AndroidRuntime(23444): FATAL EXCEPTION: GLThread
02-20 09:26:15.229: E/AndroidRuntime(23444): java.lang.NullPointerException
02-20 09:26:15.229: E/AndroidRuntime(23444):    at com.tester.test.TestGameClass.render(TestGameClass.java:71)
02-20 09:26:15.229: E/AndroidRuntime(23444):    at com.badlogic.gdx.backends.android.AndroidGraphics.onDrawFrame(AndroidGraphics.java:499)
02-20 09:26:15.229: E/AndroidRuntime(23444):    at com.badlogic.gdx.backends.android.surfaceview.GLSurfaceViewCupcake$GLThread.guardedRun(GLSurfaceViewCupcake.java:713)
02-20 09:26:15.229: E/AndroidRuntime(23444):    at com.badlogic.gdx.backends.android.surfaceview.GLSurfaceViewCupcake$GLThread.run(GLSurfaceViewCupcake.java:646)

The LogCat error seems to point to the render section of my game class:

import com.badlogic.gdx.ApplicationListener;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.assets.AssetManager;
import com.badlogic.gdx.audio.Music;
import com.badlogic.gdx.audio.Sound;
import com.badlogic.gdx.graphics.GL10;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;
import com.badlogic.gdx.utils.Array;

public class TestGameClass implements ApplicationListener {

AssetManager manager = new AssetManager();
Texture grey_background;
Texture tell_arrow;
Texture test_anni_1;
Music test_intro;
Music test_play;
Sound menu_select;
OrthographicCamera camera;
SpriteBatch batch;
TextureAtlas spriteSheet;
private Array<Sprite> test;
private int currentFrame;
private float frameLength;
private float animationElapsed;

@Override
   public void create () {

    Texture.setEnforcePotImages(false);
    grey_background = new Texture(Gdx.files.internal("grey_background.png"));
    tell_arrow = new Texture(Gdx.files.internal("tell_arrow.png"));
    test_intro = Gdx.audio.newMusic(Gdx.files.internal("test_intro.mp3"));
    test_play = Gdx.audio.newMusic(Gdx.files.internal("test_play.mp3"));
    menu_select = Gdx.audio.newSound(Gdx.files.internal("menu_select.wav"));

    test_intro.setLooping(true);
    test_intro.play();

     camera = new OrthographicCamera();
     camera.setToOrtho(false, 480, 640);

    spriteSheet = new TextureAtlas( Gdx.files.internal( "spritesheet.txt" ));
    test = spriteSheet.createSprites("test");

     for(int i=0; i<test.size; i++){
         test.get(i).setSize(3.0f, 3.0f);
     }

     float dt = Gdx.graphics.getDeltaTime();
     animationElapsed += dt;
     while(animationElapsed > frameLength){
         animationElapsed -= frameLength;
         currentFrame = (currentFrame == test.size - 1) ? 0 : ++currentFrame;
     }

    }

   @Override
   public void render() {
       Gdx.gl.glClearColor(0, 0, 0.2f, 1);
          Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

       camera.update();
       batch.begin();
       test.get(currentFrame).draw(batch);
       batch.end();
       }

   public void resize (int width, int height) { 
   }

   public void pause () { 
   }

   public void resume () {
   }

   public void dispose () { 
       grey_background.dispose();
       menu_select.dispose();
       test_intro.dispose();
       test_play.dispose();
       tell_arrow.dispose();
       batch.dispose();
   }
}

My Texturepacker png image and text document refer to each test frame as test1, test2, test3 etc.

I was previously getting errors that pointed to the line associated with OpenGL, and separately, with the line associated with camera settings. I seemed to have solved them, but perhaps this is related?

Thanks.

Answer 1

You havnt initialize batch. insert
batch = new SpriteBatch();
in your create() method.
Apart form this , your code
float dt = Gdx.graphics.getDeltaTime(); animationElapsed += dt; while(animationElapsed > frameLength){ animationElapsed -= frameLength; currentFrame = (currentFrame == test.size - 1) ? 0 : ++currentFrame; }
should be placed inside render() .