LibGDX检测碰撞问题，Android Studio

Question

我的游戏几乎已经准备好了，然而，当我添加障碍物碰撞并将其设置为玩家活着时，圆圈就会继续前进，就像障碍物不是敌人一样，我该如何解决这个问题呢？这是MainGame.java中的代码：

package com.circlecrashavoider;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Contact;
import com.badlogic.gdx.physics.box2d.ContactImpulse;
import com.badlogic.gdx.physics.box2d.ContactListener;
import com.badlogic.gdx.physics.box2d.Manifold;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.utils.viewport.FitViewport;
import com.circlecrashavoider.entities.FloorEntity;
import com.circlecrashavoider.entities.ObstacleEntity;
import com.circlecrashavoider.entities.PlayerEntity;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/**
 * Created by Felipe on 2/22/2016.
 */

public class GameScreen extends BaseScreen {

    private Stage stage;

    private World world;

    private PlayerEntity player;

    private List<FloorEntity> floorList = new ArrayList<FloorEntity>();

    private List<ObstacleEntity> obstacleList = new ArrayList<ObstacleEntity>();

    public GameScreen(MainGame game) {
        super(game);
        stage = new Stage(new FitViewport(1024, 620));
        world = new World(new Vector2(0, -10), true);


        world.setContactListener(new ContactListener() {

            private boolean areCollided(Contact contact, Object userA, Object userB) {
                Object userDataA = contact.getFixtureA().getUserData();
                Object userDataB = contact.getFixtureB().getUserData();


                if (userDataA == null || userDataB == null) {
                    return false;
                }


                return (userDataA.equals(userA) && userDataB.equals(userB)) ||
                        (userDataA.equals(userB) && userDataB.equals(userA));
            }

            @Override
            public void beginContact(Contact contact) {
                if (areCollided(contact, "player", "floor")) {
                    player.setJumping(false);
                }

                if (areCollided(contact, "player", "obstacle")) {
                    if (player.isAlive()) {
                        player.setAlive(false);
                    }
                }
            }

            @Override
            public void endContact(Contact contact) {

            }

            @Override
            public void preSolve(Contact contact, Manifold oldManifold) {

            }

            @Override
            public void postSolve(Contact contact, ContactImpulse impulse) {

            }
        });
    }

    @Override
    public void show() {
        Texture playerTexture = game.getManager().get("player.png");
        Texture floorTexture = game.getManager().get("floor.png");
        Texture overfloorTexture = game.getManager().get("overfloor.png");
        Texture obstacleTexture = game.getManager().get("obstacle.png");


        player = new PlayerEntity(world, playerTexture, new Vector2(1, 2));

        floorList.add(new FloorEntity(world, floorTexture, overfloorTexture, 0, 1000, 1));
        obstacleList.add(new ObstacleEntity(world, obstacleTexture, 6, 1));
        stage.addActor(player);
        for (FloorEntity floor : floorList) {
            stage.addActor(floor);
        }
        for (ObstacleEntity obstacle : obstacleList) {
            stage.addActor(obstacle);
        }
    }

    @Override
    public void hide() {
        player.detach();
        player.remove();
            for (FloorEntity floor: floorList) {
                floor.detach();
                floor.remove();
            }
            for (ObstacleEntity obstacle: obstacleList) {
                obstacle.detach();
                obstacle.remove();
            }

    }

    @Override
    public void render(float delta) {
        Gdx.gl20.glClearColor(0.5f, 0.6f, 1, 3f);
        Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT);

        stage.act();
        world.step(delta, 6 ,2);
        stage.draw();
    }

    @Override
    public void dispose() {
        stage.dispose();
        world.dispose();
    }
}

以下是您需要更多信息的下载链接，这是我完成游戏所需要做的最后一件事。

http://www.mediafire.com/download/992ys6adq4s6s4y/CircleCrashAvoider.7z