Question

在visual studio中运行的基本cocos2dx应用程序中出现链接器错误。当AppDelegate的“applicationDidFinishLaunching”方法调用“MyGameScene”的“singleton”方法时发生。我已经检查过MyGameScene.h中定义的方法是在MyGameScene.cpp类中实现的

错误消息

Error   1   error LNK2019: unresolved external symbol "public: static class
MyGame * __cdecl MyGame::singleton(void)" (?singleton@MyGame@@SAPAV1@XZ) 
referenced in function "public: virtual bool __thiscall 
AppDelegate::applicationDidFinishLaunching(void)" 
(?applicationDidFinishLaunching@AppDelegate@@UAE_NXZ)   D:\Dev\cocos2d-2.0-x-
2.0.4\MyGame\proj.win32\AppDelegate.obj MyGame

AppDelegate.h

#ifndef  _APP_DELEGATE_H_
#define  _APP_DELEGATE_H_

#include "CCApplication.h"

/**
@brief    The cocos2d Application.

The reason for implement as private inheritance is to hide some interface call by   CCDirector.
*/
class  AppDelegate : private cocos2d::CCApplication
{
public:
AppDelegate();
virtual ~AppDelegate();

/**
@brief    Implement CCDirector and CCScene init code here.
@return true    Initialize success, app continue.
@return false   Initialize failed, app terminate.
*/
virtual bool applicationDidFinishLaunching();

/**
@brief  The function be called when the application enter background
@param  the pointer of the application
*/
virtual void applicationDidEnterBackground();

/**
@brief  The function be called when the application enter foreground
@param  the pointer of the application
*/
virtual void applicationWillEnterForeground();
};

#endif // _APP_DELEGATE_H_

AppDelegate.cpp

#include "AppDelegate.h"
#include "cocos2d.h"
#include "MyGameScene.h"

USING_NS_CC;

AppDelegate::AppDelegate()
{

}

AppDelegate::~AppDelegate()
{
}

bool AppDelegate::applicationDidFinishLaunching()
{
// initialize director
CCDirector *pDirector = CCDirector::sharedDirector();
pDirector->setOpenGLView(CCEGLView::sharedOpenGLView());

// turn on display FPS
pDirector->setDisplayStats(true);

// set FPS. the default value is 1.0/60 if you don't call this
pDirector->setAnimationInterval(1.0 / 60);

// create a scene. it's an autorelease object
MyGame *MyGame = MyGame::singleton();
CCScene *pScene = MyGame->scene();

// run
pDirector->runWithScene(pScene);

return true;
}

// This function will be called when the app is inactive. When comes a phone call,it's be invoked too
void AppDelegate::applicationDidEnterBackground()
{

CCDirector::sharedDirector()->pause();

// if you use SimpleAudioEngine, it must be pause
// SimpleAudioEngine::sharedEngine()->pauseBackgroundMusic();
}

// this function will be called when the app is active again
void AppDelegate::applicationWillEnterForeground()
{

CCDirector::sharedDirector()->resume();

// if you use SimpleAudioEngine, it must resume here
// SimpleAudioEngine::sharedEngine()->resumeBackgroundMusic();
}

MyGameScene.h

#ifndef __MYGAME_SCENE_H__
#define __MYGAME_SCENE_H__

#include "cocos2d.h"
#include "Box2D/Box2d.h"

#define PTM_RATIO 32

USING_NS_CC;
class MyGame: public cocos2d::CCLayer {
public:

    cocos2d::CCSprite *_ball;

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

    static MyGame *singleton();

    MyGame();
    ~MyGame();

    // 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 recommand to return the exactly class pointer
    cocos2d::CCScene* scene();

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

    void Tick(float dt);

private:
    CCScene *_scene;

    int mWidth;
    int mHeight;

};

#endif // __MYGAME_SCENE_H__

MyGameScene.cpp

    #include "MyGameScene.h"
//#include "SimpleAudioEngine.h"
#include "Shaders.h"

using namespace cocos2d;
//using namespace CocosDenshion;

#define COCOS2D_DEBUG 1

extern "C" {
#include <pthread.h>
#include <unistd.h>
}

static MyGame *_MyGameSingleton = NULL;
static bool mIsNewFrameReceived;

MyGame* MyGame::singleton() {
    // 'layer' is an autorelease object
    if (_MyGameSingleton == NULL) {
        _MyGameSingleton = MyGame::create();

    }
    return _MyGameSingleton;
}

CCScene* MyGame::scene() {
    if (!_scene) {
        // 'scene' is an autorelease object
        _scene = CCScene::create();

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

    // return the scene
    return _scene;
}

// on "init" you need to initialize your instance
bool MyGame::init() {
    _scene = NULL;

    if (!CCLayer::init()) {
        return false;
    }
//  CCLOG("init");
//  CCSize winSize = CCDirector::sharedDirector()->getWinSize();
//  mWidth = winSize.width;
//  mHeight = winSize.height;
    this->schedule(schedule_selector(MyGame::Tick));

    return true;
}

void MyGame::menuCloseCallback(CCObject* pSender) {
    CCDirector::sharedDirector()->end();

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

MyGame::~MyGame() {

}


MyGame::MyGame() {

}

void MyGame::Tick(float dt) {
    CCDirector *director = CCDirector::sharedDirector();
    CCSize windowSize = director->getVisibleSize();
    mWidth = windowSize.width;
    mHeight = windowSize.height;
}

更新我在Visual Studio本身的项目中创建了一个新类，并将MyGame类的所有变量和成员函数复制到它。然后，我能够引用新类并正确编译。

[在这里复制我的评论] 我能够使用cygwin在Windows上编译现有的cocos2dx游戏，我的同事可以使用XCode在Mac上编译相同的东西。问题仅在使用Visual Studio

进行编译时

我认为Visual Studio没有编译MyGame文件。我如何确保将编译该类？

Answer 1

您是否尝试在.cpp文件的顶部设置静态MyGame var？

static MyGame *singleton();

如果未在任何位置设置，则生成此错误。

Answer 2

我猜这是一个错字。错误消息确实包含足够的信息。 “public：static ----- class ---- MyGame * __cdecl ...“

MyGame *MyGame

应该是

MyGame *myGame

在AppdDeleate.cpp

中

Answer 3

我发现从模板创建项目后我没有正确链接cocos2dx库。这就是链接器错误的原因[虽然错误指向了我的不同方向]。
谢谢大家的帮助！
我计划列出正确的步骤，我稍后使用，在现有的cocos2dx项目中为Visual Studio 2012创建一个win32项目，对于那些访问此类问题但遇到类似问题的人来说。

LNK2019功能中未解析的外部符号引用

3 个答案: