Question

在将cocos2d-x项目从iOS移植到Android时，我发现了一个会导致Android崩溃而不是iOS上的问题，为了显示这个问题，我对HelloWorld示例进行了一些小修改。要重现此问题，只需按下右下角的关闭按钮，在Android上它会崩溃但不会在iOS上崩溃。

导致崩溃的代码是：

void TestNode::test()
{
    // This will cause crash on Android, but OK on iOS
    CCCallFunc *selector = CCCallFunc::create(this, callfunc_selector(TestNode::destroy));
    this->runAction(selector);

    // This is ok on both Android and iOS
//    CCCallFunc *selector = CCCallFunc::create(scene_, callfunc_selector(HelloWorld::destroyNode));
//    scene_->runAction(selector);

    // This is ok on both Android and iOS
//    destroy();
}

完整的代码如下：

HelloWorldScene.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h" 

class TestNode : public cocos2d::CCNode {
    public:
        TestNode(cocos2d::CCLayer *scene);
        ~TestNode();

        void test();
        void destroy();

        cocos2d::CCLayer *scene_;
        cocos2d::CCSprite *sprite_;
};

class HelloWorld : public cocos2d::CCLayer
{
private:
    TestNode *node_;
public:
    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    virtual bool init();  

    // there's no 'id' in cpp, so we recommend returning the class instance pointer
    static cocos2d::CCScene* scene();

    // a selector callback
    void menuCloseCallback(CCObject* pSender);

    // implement the "static node()" method manually
    CREATE_FUNC(HelloWorld);

    void destroyNode();
};

#endif // __HELLOWORLD_SCENE_H__

HelloWorldScene.cpp：

#include "HelloWorldScene.h" 
#include "AppMacros.h" 
USING_NS_CC;

TestNode::TestNode(cocos2d::CCLayer *scene):
    scene_(scene)
{
    sprite_ = CCSprite::create("CloseNormal.png");
    sprite_->setPosition(ccp(200, 200));
    scene_->addChild(sprite_, 255);
}

TestNode::~TestNode()
{
    scene_->removeChild(sprite_, true);
    scene_->removeChild(this, true);
    CCLog("+++ ~TestNode");
}

void TestNode::test()
{
    // This will cause crash on Android, but OK on iOS
    CCCallFunc *selector = CCCallFunc::create(this, callfunc_selector(TestNode::destroy));
    this->runAction(selector);

    // This is ok on both Android and iOS
//    CCCallFunc *selector = CCCallFunc::create(scene_, callfunc_selector(HelloWorld::destroyNode));
//    scene_->runAction(selector);

    // This is ok on both Android and iOS
//    destroy();
}

void TestNode::destroy()
{
    CCLog("+++ destroy");
    delete this;
}

CCScene* HelloWorld::scene()
{
    // 'scene' is an autorelease object
    CCScene *scene = CCScene::create();

    // 'layer' is an autorelease object
    HelloWorld *layer = HelloWorld::create();

    // add layer as a child to scene
    scene->addChild(layer);

    // return the scene
    return scene;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !CCLayer::init() )
    {
        return false;
    }

    CCSize visibleSize = CCDirector::sharedDirector()->getVisibleSize();
    CCPoint origin = CCDirector::sharedDirector()->getVisibleOrigin();

    /////////////////////////////
    // 2. add a menu item with "X" image, which is clicked to quit the program
    //    you may modify it.

    // add a "close" icon to exit the progress. it's an autorelease object
    CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
                                        "CloseNormal.png",
                                        "CloseSelected.png",
                                        this,
                                        menu_selector(HelloWorld::menuCloseCallback));

    pCloseItem->setPosition(ccp(origin.x + visibleSize.width - pCloseItem->getContentSize().width/2 ,
                                origin.y + pCloseItem->getContentSize().height/2));

    // create menu, it's an autorelease object
    CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
    pMenu->setPosition(CCPointZero);
    this->addChild(pMenu, 1);

    /////////////////////////////
    // 3. add your codes below...

    // add a label shows "Hello World" 
    // create and initialize a label

    CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", TITLE_FONT_SIZE);

    // position the label on the center of the screen
    pLabel->setPosition(ccp(origin.x + visibleSize.width/2,
                            origin.y + visibleSize.height - pLabel->getContentSize().height));

    // add the label as a child to this layer
    this->addChild(pLabel, 1);

    // add "HelloWorld" splash screen" 
    CCSprite* pSprite = CCSprite::create("HelloWorld.png");

    // position the sprite on the center of the screen
    pSprite->setPosition(ccp(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));

    // add the sprite as a child to this layer
    this->addChild(pSprite, 0);

    node_ = new TestNode(this);
    this->addChild(node_);

    return true;
}

void HelloWorld::menuCloseCallback(CCObject* pSender)
{
//    CCDirector::sharedDirector()->end();
    if (node_) {
        node_->test();
        node_ = NULL;
    }

//#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
//    exit(0);
//#endif
}

void HelloWorld::destroyNode()
{
    node_->destroy();
}

Answer 1

我不知道为什么这适用于iOS，但你不应该这样做。当您运行代码时

CCCallFunc *selector = CCCallFunc::create(this, callfunc_selector(TestNode::destroy));
this->runAction(selector);

调用函数

void TestNode::destroy()
{
    CCLog("+++ destroy");
    delete this;
}

你正在销毁一个CCCallFunc动作仍保持指针的对象。然后，当CCCallFunc对象被销毁时，它会运行CC_SAFE_RELEASE宏，该宏将在TestNode对象上调用release。但是，到目前为止，TestNode对象已经被释放，这很可能是导致崩溃的原因。

一个cocos2d-x代码导致Android崩溃，但不会导致iOS崩溃

1 个答案: