android - すべてのメソッドが適切に宣言および初期化されているにもかかわらず、cocos2d-android で Null ポインター例外エラーが発生する

Question

cocos2d-android を使用したゲーム アプリのコーディングを行いましたが、プロジェクトを実行すると、ゲーム レイヤーの画面の Ontouch で強制的に閉じられます。およびlogcatでnullポインター例外が発生しますが、すべてのオブジェクトと変数が正しく宣言されています。
このメソッドでは、Java ファイルの public boolean ccTouchesEnded(MotionEvent event)_nextProjectile;が正しく宣言されていますが、それでもヌル ポインター例外が多すぎます。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();
}

ログトレース。

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)