Box2D Forums

   private PhysicsThread thread;
   SurfaceHolder surfaceHolder;
   private World world;
   private BodyDef groundBodyDef = new BodyDef();
   private BodyDef bodyDef = new BodyDef();
   private FixtureDef fixtureDef = new FixtureDef();
   private PolygonShape groundBox = new PolygonShape();
   private Body groundBody, body, circleA, circleB, circleC;
   private CircleShape csA, csB, csC;
   private BodyDef circleADef = new BodyDef(), circleBDef = new BodyDef(),
         circleCDef = new BodyDef();
   private MouseJointDef md;
   private MouseJoint mj;
   private int pitch;
   private int roll;

   public PhysicsView(Context context, AttributeSet attrs) {
      super(context, attrs);
      getHolder().addCallback(this);
      thread = new PhysicsThread(getHolder(), this);
      setFocusable(true);
   }

   @Override
   public void surfaceChanged(SurfaceHolder holder, int format, int width,
         int height) {
   }

   @Override
   public void surfaceCreated(SurfaceHolder holder) {
      Vec2 gravity = new Vec2((float) 0.0, (float) 10.0);
      boolean doSleep = true;
      
       
      world = new World(gravity, doSleep);
   
      groundBodyDef = new BodyDef();
      groundBodyDef.position.set(50.0f, 50.0f);
      groundBody = world.createBody(groundBodyDef);
                                       
      groundBox = new PolygonShape();
      groundBox.setAsBox(50.0f, 50.0f);
      groundBody.createFixture(groundBox, 0.0f);

      // dynamic Body
      bodyDef.type = BodyType.DYNAMIC;
      bodyDef.position.set(0.0f, 4.0f);
      body = world.createBody(bodyDef);

      PolygonShape dynamicBox = new PolygonShape();
      dynamicBox.setAsBox(1.0f, 1.0f);

      // Circle A
      circleADef.type = BodyType.DYNAMIC;
      circleADef.position.set(100.0f, 100.0f);
      circleA = world.createBody(circleADef);

      csA = new CircleShape();
      csA.m_p.set(2.0f, 3.0f);
      csA.m_radius = 10.0f;

      // Circle B
      circleBDef.type = BodyType.DYNAMIC;
      circleBDef.position.set(200.0f, 200.0f);
      circleB = world.createBody(circleBDef);

      csB = new CircleShape();
      csB.m_p.set(2.0f, 3.0f);
      csB.m_radius = 50.5f;

      // Circle C – Static for testing
      circleCDef.type = BodyType.STATIC;
      circleCDef.position.set(200.0f, 400.0f);
      circleC = world.createBody(circleCDef);

      csC = new CircleShape();
      csC.m_p.set(2.0f, 3.0f);
      csC.m_radius = 50.5f;

      fixtureDef.shape = dynamicBox;
      fixtureDef.density = 1.0f;
      fixtureDef.friction = 0.3f;

      body.createFixture(fixtureDef);

      thread.setRunning(true);
      thread.start();

   }