AndEngine Sprite/Box2D Body 移除使我的程序崩溃而没有错误/异常信息? [英] AndEngine Sprite/Box2D Body removal crashes my program with no error/exception information?
问题描述
我正在制作一个带有障碍物的滑板游戏，你必须使用 box2D 和 AndEngine 跳过.我试图做到这一点，当玩家与一个物体发生碰撞时，该物体被移除并在物体的旧位置放置一个爆炸，但是精灵移除代码中的某些东西冻结了我的程序导致它结束(甚至不是一个强制关闭消息它只是自行关闭并进入我的主屏幕)并且 logcat 中没有出现错误/异常信息，所以我不知道是什么原因造成的！下面是一些代码片段-
I am making a skateboarding game with obstacles you have to jump over using box2D and AndEngine. I am trying to make it so that when the player collides with an object, the object is removed and an explosion is placed at the objects old position, however something in the sprite removal code is freezing my program causing it to end (not even a force close message it just closes itself and goes to my home screen) and no error/exception information appears in logcat so I have no idea what is causing it! Here are some code snippets-
当我创建精灵/边界时，我将一个 JSONObject 附加到包含精灵和精灵类型的主体，并将类似的 JSONOBject 附加到具有主体和类型的精灵:
when I create the sprites/boundaries I attach a JSONObject to the body containing the sprite and the type of sprite it is, and attach a similar JSONOBject to the sprite with the body and type:
/** method to construct our player (takes an x and y position)*/
private void constructPlayer(final float pX, final float pY) {
final Body body;
/* construct the sprite of our player and set the animation */
this.player = new AnimatedSprite(pX, pY, this.mSkaterTextureRegion);
long[] frameDurations = {100, 100};
player.animate(frameDurations, 4, 5, true);
body = PhysicsFactory.createBoxBody(this.mPhysicsWorld, player, BodyType.DynamicBody, PLAYER_FIXTURE_DEF);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(player, body, true, false));
body.setUserData(makeUserDataForBody(PLAYER_TYPE,player));
player.setUserData(makeUserDataForSprite(PLAYER_TYPE,body));
this.mScene.registerTouchArea(player);
//attach our player to the scene
this.mScene.attachChild(player);
}
private JSONObject makeUserDataForBody(int type, Object sprite)
{
JSONObject myObject = new JSONObject();
try {
myObject.put("type", type);
myObject.put("sprite", sprite);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return myObject;
}
private JSONObject makeUserDataForSprite(int type, Body body)
{
JSONObject myObject = new JSONObject();
try {
myObject.put("body", body);
myObject.put("type", type);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return myObject;
}
我用于构建障碍精灵的代码与构建播放器几乎相同，但我为其设置了移动速度:
My code for the constructing the obstruction sprites is pretty much the same as constructing the player but I set a velocity for it to move:
private void addObstruction(final float pX, final float pY) {
final Body body;
final Sprite myObstruction;
myObstruction = new Sprite(pX, pY, this.mCrateTextureRegion);
body = PhysicsFactory.createBoxBody(this.mPhysicsWorld, myObstruction, BodyType.DynamicBody, OBJECT_FIXTURE_DEF);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(myObstruction, body, true, true));
body.setUserData(makeUserDataForBody(OBSTRUCTION_TYPE,myObstruction));
myObstruction.setUserData(makeUserDataForSprite(OBSTRUCTION_TYPE,body));
body.setLinearVelocity(-150f, 0);
//attach our Obstruction to the scene
this.mScene.attachChild(myObstruction);
}
这是我的物理世界的contactListener:
Here is the contactListener for my physics world:
this.mPhysicsWorld.setContactListener(new ContactListener() {
@Override
public void preSolve(Contact contact, Manifold oldManifold) {
}
@Override
public void postSolve(Contact contact, ContactImpulse impulse) {
}
@Override
public void endContact(Contact contact) {
// TODO Auto-generated method stub
Body obj1Data = contact.getFixtureA().getBody();
Body obj2Data = contact.getFixtureB().getBody();
JSONObject obj1UserData;
JSONObject obj2UserData;
int obj1Type = 0;
int obj2Type = 0;
if(obj1Data.getUserData()!=null)
{
obj1UserData =(JSONObject) obj1Data.getUserData();
try {
obj1Type = obj1UserData.getInt("type");
}catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(obj2Data.getUserData()!=null)
{
obj2UserData=(JSONObject) obj2Data.getUserData();
try {
obj2Type = obj2UserData.getInt("type");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
switch (obj1Type)
{
case PLAYER_TYPE:
break;
case GRINDRAIL_TYPE:
if(isGrinding)
{
endGrind();
if(!isJumping)
fall(player);
}
break;
case GROUND_TYPE:
break;
case OBSTRUCTION_TYPE:
break;
case WALL_TYPE:
break;
}
switch (obj2Type)
{
case PLAYER_TYPE:
break;
case GRINDRAIL_TYPE:
if(isGrinding)
{
endGrind();
if(!isJumping)
fall(player);
}
break;
case GROUND_TYPE:
break;
case OBSTRUCTION_TYPE:
break;
case WALL_TYPE:
break;
}
}
@Override
public void beginContact(Contact contact) {
Body obj1Data = contact.getFixtureA().getBody();
Body obj2Data = contact.getFixtureB().getBody();
JSONObject obj1UserData;
JSONObject obj2UserData;
int obj1Type = 0;
int obj2Type = 0;
if(obj1Data.getUserData()!=null)
{
obj1UserData =(JSONObject) obj1Data.getUserData();
try {
obj1Type = obj1UserData.getInt("type");
}catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(obj2Data.getUserData()!=null)
{
obj2UserData=(JSONObject) obj2Data.getUserData();
try {
obj2Type = obj2UserData.getInt("type");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//deal with things colliding with the player
if(obj1Type==PLAYER_TYPE)
{
playerCollisionHandler(obj2Data);
}
else if(obj2Type==PLAYER_TYPE)
{
playerCollisionHandler(obj1Data);
}
}
});
这是我的 playerCollisionHandler 方法:
here is my playerCollisionHandler method:
private void playerCollisionHandler(Body secondBody)
{
JSONObject secondBodyData = null;
if(secondBody.getUserData()!=null)
{
secondBodyData=(JSONObject) secondBody.getUserData();
}
JSONObject userdata = (JSONObject) player.getUserData();
Body playerBody = null;
try {
playerBody = (Body) userdata.get("body");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
int objType = 0;
try {
if(secondBodyData!=null)
objType = secondBodyData.getInt("type");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(objType == GROUND_TYPE)
{
if(playerBody.getLinearVelocity().y<0)
{
/* If the sprites y velocity is negative the sprite is jumping,
* don't reset the values!!!*/
}
else
{
if((isJumping)||(isFalling))
{
//play landing sound
AndEngineTestActivity.this.mLandSound.play();
isJumping = false;
isFalling = false;
//player.setPosition(player.getX(), GROUND_LEVEL-player.getHeight());
//animate landing
player.animate(createFrameDurations(LAND_ANIM_FRAMES.length), LAND_ANIM_FRAMES, 0);
}
if(!rollSoundIsPlaying)
{
playRollSound();
}
}
}
else if(objType == GRINDRAIL_TYPE)
{
Sprite grindRail=null;
try {
grindRail = (Sprite) secondBodyData.get("sprite");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/*create a rectangle at the upper bound of the grind rail to test collision*/
grindRailUpperBound = new Rectangle(grindRail.getX(), grindRail.getY(), mGrindRailTextureRegion.getWidth(), COLLISION_BOUNDS_PIXEL_ACCURACY);
playerLowerBound = new Rectangle(player.getX(), player.getY()+player.getHeight(), player.getWidth(), COLLISION_BOUNDS_PIXEL_ACCURACY);
grindRailUpperBound.setColor(1.0f, 0f, 0f,1f);
playerLowerBound.setColor(1.0f, 1.0f, 0f,1f);
mScene.attachChild(playerLowerBound);
mScene.attachChild(grindRailUpperBound);
if(grindRailUpperBound.collidesWith(playerLowerBound))
{
if(!isGrinding)
{
mScene.detachChild(grindRailUpperBound);
mScene.detachChild(playerLowerBound);
grindPlayer(player);
}
}
if(!isGrinding)
{
/* if it reaches this point and the custom rectangle bounds did not collide
* it means the player has collided with the grind rail another way, so we hurt the player*/
playerHitByObject();
destroyObstruction(secondBody);
}
}
else if(objType == OBSTRUCTION_TYPE)
{
playerHitByObject();
destroyObstruction(secondBody);
}
}
这里是 destroyObtruction 方法，它似乎是崩溃的罪魁祸首(如果我注释掉我对 destroyObstruction 的调用，我的代码运行良好，但我不确定为什么这个方法会导致崩溃......):
and here is the destroyObtruction method which seems to be the culprit of the crashes (if i comment out my calls to destroyObstruction my code runs fine, but I'm not sure why this method is causing the crash...):
private void destroyObstruction(Body obstructionBody)
{
obstructionBody.setActive(false);
try{
JSONObject secondBodyData = null;
if(obstructionBody.getUserData()!=null)
{
secondBodyData=(JSONObject) obstructionBody.getUserData();
}
explodeObstruction(((IEntity) secondBodyData.get("sprite")).getX(),((IEntity) secondBodyData.get("sprite")).getY());
final PhysicsConnector obstructionPhysicsConnector = this.mPhysicsWorld.getPhysicsConnectorManager().findPhysicsConnectorByShape((IShape) secondBodyData.get("sprite"));
this.mPhysicsWorld.unregisterPhysicsConnector(obstructionPhysicsConnector);
this.mPhysicsWorld.destroyBody(obstructionPhysicsConnector.getBody());
//this.mPhysicsWorld.destroyBody(obstructionBody);
this.mScene.detachChild((IEntity) secondBodyData.get("sprite"));
}catch(Exception e)
{
Log.d(TAG, "Exception:"+e);
}
catch(Error e)
{
Log.d(TAG, "Error:"+e);
}
}
private void explodeObstruction(float pX, float pY)
{
PointParticleEmitter obstructionExplosion = new PointParticleEmitter(pX, pY);
ParticleSystem ExplosionParticleSystem = new ParticleSystem(obstructionExplosion, 45, 60, 60, this.mCrateParticleTextureRegion);
ExplosionParticleSystem.addParticleInitializer(new AlphaInitializer(1f));
ExplosionParticleSystem.setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE);
ExplosionParticleSystem.addParticleInitializer(new VelocityInitializer(-175, 175, -175, 175));
ExplosionParticleSystem.addParticleInitializer(new RotationInitializer(0.0f, 360.0f));
ExplosionParticleSystem.addParticleInitializer(new RotationInitializer(0f, -20f));
ExplosionParticleSystem.addParticleModifier(new ScaleModifier(1.0f, 0.5f, 0, MAX_PARTICLE_LIFE/2));
ExplosionParticleSystem.addParticleModifier(new AlphaModifier(1, 0.35f, 0, MAX_PARTICLE_LIFE));
ExplosionParticleSystem.addParticleModifier(new ExpireModifier(MAX_PARTICLE_LIFE, MAX_PARTICLE_LIFE));
this.mScene.attachChild(ExplosionParticleSystem);
}
推荐答案
在谷歌搜索 box2D 和 sprite/body 移除之后，结果你不能从 contactListener 中移除 sprite/body，但是你可以做的是设置一个主体或精灵中的标志以将其删除并在 contactListener 之外的单独更新方法中检查这些标志.我通过创建一个 'makeUserData' 方法来创建一个带有 sprite/body/type 的 JSONObject 以及一个布尔值 'deleteStatus' 来确定它是否标记为删除:
After googling about box2D and sprite/body removal it turns out you can't remove a sprite/body from the contactListener, but what you can do is set a flag in either the body or sprite to delete it and check for these flags in a seperate update method outside the contactListener. I did this by making a single 'makeUserData' method to create a JSONObject with the sprite/body/type and additionally a boolean 'deleteStatus' that determines if it flagged for deletion:
private JSONObject makeUserData(int type, Body body, Object sprite)
{
JSONObject myObject = new JSONObject();
try {
myObject.put("type", type);
myObject.put("sprite", sprite);
myObject.put("body", body);
myObject.put("deleteStatus", false);
} catch (JSONException e) {
// TODO Auto-generated catch block
Log.d(TAG,"Exception creating user data:"+e);
}
return myObject;
}
然后不是在碰撞后调用destroyObstruction()，而是调用我创建的这个方法来将主体内的删除标志设置为true:
Then instead of calling destroyObstruction() after collision I call this method i created to set the flag for deletion within the body to true:
private void setForDestruction(Body myBody) throws JSONException
{
if(myBody.getUserData()!=null)
{
((JSONObject)myBody.getUserData()).put("deleteStatus", true);
}
}
然后在一个单独的更新处理程序中(我的 onLoadScene 方法中已经有一个来更新分数)我添加了对另一个方法的调用，我在我的物理世界中遍历实体以寻找这个标志:
Then in a seperate update handler (I had one in my onLoadScene method already to update the score) I added a call to another method I made to iterate through the bodies in my physics world looking for this flag:
this.mScene.registerUpdateHandler(new IUpdateHandler() {
@Override
public void reset() { }
@Override
public void onUpdate(final float pSecondsElapsed) {
//update the players score
updateScore();
//update the text on the screen
playerScoreText.setText( "Score: "+PLAYER_SCORE);
playerLivesText.setText("Lives:"+PLAYER_LIVES);
//remove any sprites flagged for deletion
try{
removeObjectsSetForDestruction();
}catch(Exception e)
{
Log.d(TAG,"Exception removing objects from update:"+e);
}
catch(Error e)
{
Log.d(TAG,"Error removing objects from update:"+e);
}
}
});
这里是 removeObjectsSetForDestruction 方法:
And here is the removeObjectsSetForDestruction method:
private void removeObjectsSetForDestruction()
{
if(this.mPhysicsWorld!=null)
{
Iterator<Body> allMyBodies = this.mPhysicsWorld.getBodies();//gets all the bodies in my physics world
boolean isDelete = false;
JSONObject currentBodyData;
while(allMyBodies.hasNext())
{
try {
//this code is in a try/catch bracket because some of my bodies don't have the extra data attached
currentBodyData = (JSONObject)allMyBodies.next().getUserData();//gets the next JSONOBject from the body
if(currentBodyData!=null)
{
isDelete = (Boolean) currentBodyData.get("deleteStatus");
if(isDelete)
{
destroyObstruction((Body) currentBodyData.get("body"));
}
}
} catch (JSONException e) {
// TODO Auto-generated catch block
Log.d(TAG,"Error getting world bodies data:"+e);
}
}
}
}
box2D 上的 AndEngine wiki 很好地解释了世界物理计算是如何脆弱的添加/删除/移动物体时您需要非常小心，因为在某些地方它可能与世界物理计算同时发生，最终导致程序崩溃.它还概述了将代码放入this.runOnUpdateThread"的解决方案.因此，例如在我的代码中，当我在我的代码中添加了一个障碍精灵(它们是从 CountDownTimer 添加的，因此它们有可能与世界步长计算同时添加)我将它包装在一个线程中:
The AndEngine wiki on box2D explains pretty well how the world physics calculation is fragile so you need to be really careful when adding/deleting/moving bodies as in some places it could happen at the same time as the world physics calculation, which eventually causes the program to crash. It also outlines a solution which is to place the code into 'this.runOnUpdateThread'. So for example in my code when I added an obstruction sprite in my code (they are added from a CountDownTimer so the chances that they could be added at the same time as world step calculation is likely) I wrapped it in a thread:
private void addObstruction(final float pX, final float pY) {
runOnUpdateThread(new Runnable() {
@Override
public void run() {
final Body body;
final Sprite myObstruction;
myObstruction = new Sprite(pX, pY-mCrateTextureRegion.getHeight(), mCrateTextureRegion);
body = PhysicsFactory.createBoxBody(mPhysicsWorld, myObstruction, BodyType.DynamicBody, OBJECT_FIXTURE_DEF);
//body.setLinearDamping(10);
//body.setAngularDamping(10);
mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(myObstruction, body, true, true));
body.setUserData(makeUserData(OBSTRUCTION_TYPE,body,myObstruction));
myObstruction.setUserData(makeUserData(OBSTRUCTION_TYPE,body,myObstruction));
myObstruction.registerUpdateHandler(new IUpdateHandler() {
@Override
public void reset() {
}
@Override
public void onUpdate(float pSecondsElapsed) {
runOnUpdateThread(new Runnable() {
@Override
public void run() {
final Vector2 velocity = Vector2Pool.obtain(-10f, 0f);
body.setLinearVelocity(velocity);
Vector2Pool.recycle(velocity);
}
});
}
});
//attach our Obstruction to the scene
mScene.attachChild(myObstruction);
}
});
}
我在大多数地方都使用过这些线程，我用 body 编写代码，我可以确认这阻止了我的随机崩溃:)
I've used these threads in most places I do code with bodies and I can confirm this stopped my random crashes :)
这篇关于AndEngine Sprite/Box2D Body 移除使我的程序崩溃而没有错误/异常信息?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
