java - Box2d 中动态主体为空

Question

我有一个动态 Sprite 和一些静态 Sprite 。我的动态 body :

BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyType.DynamicBody;

bodyDef.position.set(180, 20);
bodyMonkey = world.createBody(bodyDef);
PolygonShape abcBox = new PolygonShape(); 
bodyMonkey.setUserData(monkey1);
bodyMonkey.setFixedRotation(true);
abcBox.setAsBox(10.0f, 10.0f);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = abcBox;
fixtureDef.density = 0.5f; 
fixtureDef.friction = 0.0f;
fixtureDef.restitution = 0.9f; 
Fixture fixture = bodyMonkey.createFixture(fixtureDef);
abcBox.dispose();
bodyMonkey.setLinearVelocity(new Vector2(1f, 0.5f));
bodyMonkey.setLinearDamping(1.0f);

我必须实现 ContactListener。我的类(class):

@Override
public void beginContact(Contact contact) {
    Object a =  contact.getFixtureA().getBody().getUserData();
    Object b = contact.getFixtureB().getBody().getUserData();// null

    Gdx.app.log("1", ""+a);
    Gdx.app.log("2", ""+b);
    if(a!=null&&b!=null) {
        Gdx.app.log("ok", "");
        screen2dBox.restartGame();
    }
}

@Override
public void endContact(Contact contact) {
    // TODO Auto-generated method stub

}

@Override
public void preSolve(Contact contact, Manifold oldManifold) {
    // TODO Auto-generated method stub
}

@Override
public void postSolve(Contact contact, ContactImpulse impulse) {
    // TODO Auto-generated method stub
}

但是对象 b 始终为 null(a 不，b 是动态的，我在日志中看到它)。我尝试使用 try、catch、finally 来克服这个问题(在finally block 中 - screen2dBox.restartGame();)，但我遇到了错误，联系人不能为空。不知道怎么解决？感谢您的帮助。

静态主体:

BodyDef bodyDefPlatform1 = new BodyDef();
     bodyDefPlatform1.type = BodyType.StaticBody;
     bodyDefPlatform1.position.set(50, 280);
     bodyPlatform1 = world.createBody(bodyDefPlatform1 );
     PolygonShape platformBox1 = new PolygonShape();  
     bodyPlatform1.setUserData(platform);
     platformBox1.setAsBox(20.0f, 10.0f);
     FixtureDef fixtureDefPlatform1 = new FixtureDef();
     fixtureDefPlatform1.shape = platformBox1;
     Fixture fixturePlatform = bodyPlatform1.createFixture( fixtureDefPlatform1);
    platformBox1.dispose();

Answer 1

我检查了你的代码，没有发现任何错误。也许对象 Monkey1 为 null。

bodyMonkey.setUserData(monkey1); //check if monkey1 is null.

注意:我的声誉很低，我无法将此作为评论发布。