Null pointer exception error in cocos2d-android even though all the methods are declared and initialised properly

Question

For an Game app using cocos2d-android i have given coding, but when i run the project it gets force close on Ontouch of the screen in game layer. and in the logcat getting null pointer exception, but all objects and variables are declared correctly.
in this method public boolean ccTouchesEnded(MotionEvent event) in java file _nextProjectile; is declared correctly but still then too null pointer exception. public class GameL extends CCLayer{

protected LinkedList<CCSprite> _targets;
protected LinkedList<CCSprite> _projectiles;
protected int _projectilesDestroyed;
protected CCSprite _player;
protected CCSprite _nextProjectile;

public static CCScene scene()
{
    CCScene scene = CCScene.node();
    CCLayer layer = new GameL();

    scene.addChild(layer);  

    return scene;     
}
CCMenuItem item1,item2,item3;  

protected GameL()
{
 this.setIsTouchEnabled(true);

    _targets = new LinkedList<CCSprite>();
    _projectiles = new LinkedList<CCSprite>();
    _projectilesDestroyed = 0;

    CCSprite background = CCSprite.sprite("bg.png");
    background.setTag(1);
    background.setAnchorPoint(0, 0);
    addChild(background);



    CCSprite player2 = CCSprite.sprite("gun2.png");
    player2.setPosition(CGPoint.ccp(65,120));
    player2.setAnchorPoint(CGPoint.ccp(0,0));
    addChild(player2);

    this.schedule("gameLogic", 1.0f);
    this.schedule("update");
   }



@Override
public boolean ccTouchesEnded(MotionEvent event)
{
    // Choose one of the touches to work with
    CGPoint location =   CCDirector.sharedDirector().convertToGL(CGPoint.ccp(event.getX(), event.getY()));

    // Set up initial location of projectile
    CGSize winSize = CCDirector.sharedDirector().displaySize();
    _nextProjectile = CCSprite.sprite("Projectile.png");

    _nextProjectile.setPosition(20, winSize.height / 2.0f);

    // Determine offset of location to projectile
    int offX = (int)(location.x - _nextProjectile.getPosition().x);
    int offY = (int)(location.y - _nextProjectile.getPosition().y);

    // Bail out if we are shooting down or backwards
    if (offX <= 0)
        return true;

    _nextProjectile.setTag(2);

    // Determine where we wish to shoot the projectile to
    int realX = (int)(winSize.width + (_nextProjectile.getContentSize().width / 2.0f));
    float ratio = (float)offY / (float)offX;
    int realY = (int)((realX * ratio) + _nextProjectile.getPosition().y);
    CGPoint realDest = CGPoint.ccp(realX, realY);

    // Determine the length of how far we're shooting
    int offRealX = (int)(realX - _nextProjectile.getPosition().x);
    int offRealY = (int)(realY - _nextProjectile.getPosition().y);
    float length = FloatMath.sqrt((offRealX * offRealX) + (offRealY * offRealY));
    float velocity = 480.0f / 1.0f; // 480 pixels / 1 sec
    float realMoveDuration = length / velocity;

    // Move projectile to actual endpoint
    _nextProjectile.runAction(CCSequence.actions(
            CCMoveTo.action(realMoveDuration, realDest),
            CCCallFuncN.action(this, "spriteMoveFinished")));

    // Determine angle to face
    double angleRadians = Math.atan((double)offRealY / (double)offRealX);
    double angleDegrees = Math.toDegrees(angleRadians);
    double cocosAngle = -1 * angleDegrees;
    double rotationSpeed = 0.5 / Math.PI;
    double rotationDuration = Math.abs(angleRadians * rotationSpeed);
    _player.runAction(CCSequence.actions(
            CCRotateTo.action((float)rotationDuration, (float)cocosAngle),
            CCCallFunc.action(this, "finishShoot")));

    // Pew!
    Context context = CCDirector.sharedDirector().getActivity();
    SoundEngine.sharedEngine().playEffect(context, R.raw.pew_pew_lei);

    return true;
}  

public void finishShoot()
{
    addChild(_nextProjectile);
    _projectiles.add(_nextProjectile);
}

public void gameLogic(float dt)  
{
    addTarget();
}

logtrace.

05-01 09:43:50.591: E/AndroidRuntime(794): FATAL EXCEPTION: GLThread 75
05-01 09:43:50.591: E/AndroidRuntime(794): java.lang.NullPointerException
05-01 09:43:50.591: E/AndroidRuntime(794):  at  com.trialcocos.GameL.ccTouchesEnded(GameL.java:139)
05-01 09:43:50.591: E/AndroidRuntime(794):  at org.cocos2d.events.CCTouchHandler.ccTouchesEnded(CCTouchHandler.java:75)
05-01 09:43:50.591: E/AndroidRuntime(794):  at     org.cocos2d.events.CCTouchDispatcher.touchesEnded(CCTouchDispatcher.java:395)
 05-01 09:43:50.591: E/AndroidRuntime(794):     at org.cocos2d.events.CCTouchDispatcher.update(CCTouchDispatcher.java:355)
 05-01 09:43:50.591: E/AndroidRuntime(794):     at org.cocos2d.nodes.CCDirector.onDrawFrame(CCDirector.java:646)
 05-01 09:43:50.591: E/AndroidRuntime(794):     at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1516)
 05-01 09:43:50.591: E/AndroidRuntime(794):     at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1240)
05-01 09:43:52.881: E/libEGL(794): call to OpenGL ES API with no current context (logged once per thread)

score 0 · Answer 1 · answered May 08 '13 at 10:45

0

You are declaring the sprite correctly but you are not adding your sprite to your layer before running action in ccTouchesEnded method.Add your projectile to layer before running any action that.This is the reason of Exception

answered May 08 '13 at 10:45

Rishabh Bhardwaj

832
8
20

Null pointer exception error in cocos2d-android even though all the methods are declared and initialised properly

1 Answers1