Iphone 如何从cocos2d world获取b2BodyDef。。。？

我正在使用box2d创建具有不同形状的项目。。我用下面的代码创建了一个正方形； bodyDef.type=b2_dynamicBody

    bodyDef.position.Set(screenSize.width/2/PTM_RATIO,50/PTM_RATIO);
    bodyDef.userData = sprite;
    _sqrBody = world->CreateBody(&bodyDef);

    // Define another box shape for our dynamic body.
    b2PolygonShape dynamicBox;
    dynamicBox.SetAsBox(.5f, .5f);//These are mid points for our 1m box

    // Define the dynamic body fixture.
    b2FixtureDef fixtureDef;
    fixtureDef.shape = &dynamicBox; 
    fixtureDef.density = 10.0f;
    fixtureDef.friction = 0.4f;
    fixtureDef.restitution = 0.1f;
    _sqrFixture = _sqrBody->CreateFixture(&fixtureDef);`

我想移动此对象。如何移动..“CCTouchs”中的任何代码。提前感谢

body->setTransform(myposition, body->getAngle());

您可以在myposition中提供自定义位置