AndEngine 从屏幕上移除物理体答案

【问题标题】：AndEngine remove physics body from screenAndEngine 从屏幕上移除物理体
【发布时间】：2015-06-17 20:22:07
【问题描述】：

你能告诉我我的错误在哪里吗？在“physicsWorld.destroyBody(this.body)”行的 Destroy 方法中抛出异常。我正在使用最新版本的 AndEngine 和 Box2D。

public class Asteroid extends Sprite
{
    private PhysicsWorld physicsWorld;
    private PhysicsConnector physicsConnector;
    private Body body;

    public Asteroid(float pX, float pY, ITextureRegion pTextureRegion, VertexBufferObjectManager pVertexBufferObjectManager, PhysicsWorld physicsWorld)
    {
        super(pX, pY, pTextureRegion, pVertexBufferObjectManager);
        this.physicsWorld = physicsWorld;

        final FixtureDef mFixtureDef = PhysicsFactory.createFixtureDef(0, 0f, 0f);
        mFixtureDef.isSensor = true;

        this.body = PhysicsFactory.createCircleBody(physicsWorld, this, BodyDef.BodyType.DynamicBody, mFixtureDef);
        this.physicsConnector = new PhysicsConnector(this, this.body, true, true);
        physicsWorld.registerPhysicsConnector(this.physicsConnector);
        this.body.setLinearVelocity(new Vector2(0, 10));

        this.body.setUserData(this);
    }

    public void Destroy()
    {
        this.physicsWorld.unregisterPhysicsConnector(this.physicsConnector);
        this.body.setActive(false);
        physicsWorld.destroyBody(this.body); // throws Exception ???
        this.detachSelf();
    }
}

【问题讨论】：

标签： box2d andengine

【解决方案1】：

在对世界进行任何更改之前，您必须等待物理世界循环完成。所以最好的方法是创建一个elementsToBeDestroyed List，然后在世界周期更新后移除所有的body：

...
physicsWorld = new PhysicsWorld(...) {
    @Override
    public void onUpdate(float pSecondsElapsed) {
        super.onUpdate(pSecondsElapsed);
        for (Body body : elementsToBeDestroyed) {
            destroyBody(body, elementsMap.remove(body).getKey());
        }
        elementsToBeDestroyed.clear();
    }
};  
...

private void destroyBody(final Body body, final IShape mask) {
    if (physicsWorld != null) {
        physicsWorld.unregisterPhysicsConnector(physicsWorld.getPhysicsConnectorManager().findPhysicsConnectorByShape(mask));
        physicsWorld.destroyBody(body);
    }
}

【讨论】：