undefined reference to 'cocos2d::UserDefault'

Question

I have this cocos 2dx game for IOS and I want to port it to Android. I understand I have to write all my classes in the android.mk and I did. but still I have this problem

Classes/scenes/itemshop/ItemShop.cpp:144: error: undefined reference to 'cocos2d::UserDefault::GetValueForKeyPlist

this is just horrible I don't understand why I have this error, I have UserDefault class declared in android.mk

EDIT: here is some code:

CCUserDefault.h

   /****************************************************************************
    Copyright (c) 2010-2012 cocos2d-x.org
    Copyright (c) 2013-2014 Chukong Technologies Inc.

    http://www.cocos2d-x.org

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
    ****************************************************************************/
    #ifndef __SUPPORT_CCUSERDEFAULT_H__
    #define __SUPPORT_CCUSERDEFAULT_H__

    #include "base/CCPlatformMacros.h"
    #include <string>
    #include "base/CCData.h"

    NS_CC_BEGIN

    /**
     * @addtogroup data_storage
     * @{
     */

    /**
     * UserDefault acts as a tiny database. You can save and get base type values by it.
     * For example, setBoolForKey("played", true) will add a bool value true into the database.
     * Its key is "played". You can get the value of the key by getBoolForKey("played").
     * 
     * It supports the following base types:
     * bool, int, float, double, string
     */
    class CC_DLL UserDefault
    {
    public:
        // get value methods

        /**
        @brief Get bool value by key, if the key doesn't exist, a default value will return.
         You can set the default value, or it is false.
        * @js NA
        */
        bool    getBoolForKey(const char* pKey);
        /**
         * @js NA
         */
        bool    getBoolForKey(const char* pKey, bool defaultValue);
        /**
        @brief Get integer value by key, if the key doesn't exist, a default value will return.
         You can set the default value, or it is 0.
        * @js NA
        */
        int     getIntegerForKey(const char* pKey);
        /**
         * @js NA
         */
        int     getIntegerForKey(const char* pKey, int defaultValue);
        /**
        @brief Get float value by key, if the key doesn't exist, a default value will return.
         You can set the default value, or it is 0.0f.
        * @js NA
        */
        float    getFloatForKey(const char* pKey);
        /**
         * @js NA
         */
        float    getFloatForKey(const char* pKey, float defaultValue);
        /**
        @brief Get double value by key, if the key doesn't exist, a default value will return.
         You can set the default value, or it is 0.0.
        * @js NA
        */
        double  getDoubleForKey(const char* pKey);
        /**
         * @js NA
         */
        double  getDoubleForKey(const char* pKey, double defaultValue);
        /**
        @brief Get string value by key, if the key doesn't exist, a default value will return.
        You can set the default value, or it is "".
        * @js NA
        */
        std::string getStringForKey(const char* pKey);
        /**
         * @js NA
         */
        std::string getStringForKey(const char* pKey, const std::string & defaultValue);
        /**
         @brief Get binary data value by key, if the key doesn't exist, a default value will return.
         You can set the default value, or it is null.
         * @js NA
         * @lua NA
         */
        Data getDataForKey(const char* pKey);
        /**
         * @js NA
         * @lua NA
         */
        Data getDataForKey(const char* pKey, const Data& defaultValue);

        // set value methods

        /**
         @brief Set bool value by key.
         * @js NA
         */
        void    setBoolForKey(const char* pKey, bool value);
        /**
         @brief Set integer value by key.
         * @js NA
         */
        void    setIntegerForKey(const char* pKey, int value);
        /**
         @brief Set float value by key.
         * @js NA
         */
        void    setFloatForKey(const char* pKey, float value);
        /**
         @brief Set double value by key.
         * @js NA
         */
        void    setDoubleForKey(const char* pKey, double value);
        /**
         @brief Set string value by key.
         * @js NA
         */
        void    setStringForKey(const char* pKey, const std::string & value);
        /**
         @brief Set binary data value by key.
         * @js NA
         * @lua NA
         */
        void    setDataForKey(const char* pKey, const Data& value);
        /**
         @brief Save content to xml file
         * @js NA
         */
        void    flush();

        /** returns the singleton 
         * @js NA
         * @lua NA
         */
        static UserDefault* getInstance();
        /**
         * @js NA
         */
        static void destroyInstance();

        /** deprecated. Use getInstace() instead 
         * @js NA
         * @lua NA
         */
        CC_DEPRECATED_ATTRIBUTE static UserDefault* sharedUserDefault();
        /**
         * @js NA
         */
        CC_DEPRECATED_ATTRIBUTE static void purgeSharedUserDefault();
        /**
         * @js NA
         */
        static const std::string& getXMLFilePath();
        /**
         * @js NA
         */
        static bool isXMLFileExist();

        std::string GetValueForKeyPlist(std::string key);


    //    bool searchTextInPlist(std::string text);

    private:
        UserDefault();
        ~UserDefault();

        static bool createXMLFile();
        static void initXMLFilePath();

        static UserDefault* _userDefault;
        static std::string _filePath;
        static bool _isFilePathInitialized;
    };

    // end of data_storage group
    /// @}

    NS_CC_END

    #endif // __SUPPORT_CCUSERDEFAULT_H__

CCUserDefault.cpp

/****************************************************************************
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2013-2014 Chukong Technologies Inc.

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/
#include "base/CCUserDefault.h"
#include "platform/CCCommon.h"
#include "platform/CCFileUtils.h"
#include "tinyxml2.h"
#include "base/base64.h"
#include "base/ccUtils.h"

#if (CC_TARGET_PLATFORM != CC_PLATFORM_IOS && CC_TARGET_PLATFORM != CC_PLATFORM_MAC && CC_TARGET_PLATFORM != CC_PLATFORM_ANDROID)

// root name of xml
#define USERDEFAULT_ROOT_NAME    "userDefaultRoot"

#define XML_FILE_NAME "UserDefault.xml"

using namespace std;

NS_CC_BEGIN

/**
 * define the functions here because we don't want to
 * export xmlNodePtr and other types in "CCUserDefault.h"
 */

static tinyxml2::XMLElement* getXMLNodeForKey(const char* pKey, tinyxml2::XMLElement** rootNode, tinyxml2::XMLDocument **doc)
{
    tinyxml2::XMLElement* curNode = nullptr;

    // check the key value
    if (! pKey)
    {
        return nullptr;
    }

    do 
    {
        tinyxml2::XMLDocument* xmlDoc = new tinyxml2::XMLDocument();
        *doc = xmlDoc;

        std::string xmlBuffer = FileUtils::getInstance()->getStringFromFile(UserDefault::getInstance()->getXMLFilePath());

        if (xmlBuffer.empty())
        {
            CCLOG("can not read xml file");
            break;
        }
        xmlDoc->Parse(xmlBuffer.c_str(), xmlBuffer.size());

        // get root node
        *rootNode = xmlDoc->RootElement();
        if (nullptr == *rootNode)
        {
            CCLOG("read root node error");
            break;
        }
        // find the node
        curNode = (*rootNode)->FirstChildElement();
        while (nullptr != curNode)
        {
            const char* nodeName = curNode->Value();
            if (!strcmp(nodeName, pKey))
            {
                break;
            }

            curNode = curNode->NextSiblingElement();
        }
    } while (0);

    return curNode;
}

static void setValueForKey(const char* pKey, const char* pValue)
{
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    // check the params
    if (! pKey || ! pValue)
    {
        return;
    }
    // find the node
    node = getXMLNodeForKey(pKey, &rootNode, &doc);
    // if node exist, change the content
    if (node)
    {
        if (node->FirstChild())
        {
            node->FirstChild()->SetValue(pValue);
        }
        else
        {
            tinyxml2::XMLText* content = doc->NewText(pValue);
            node->LinkEndChild(content);
        }
    }
    else
    {
        if (rootNode)
        {
            tinyxml2::XMLElement* tmpNode = doc->NewElement(pKey);//new tinyxml2::XMLElement(pKey);
            rootNode->LinkEndChild(tmpNode);
            tinyxml2::XMLText* content = doc->NewText(pValue);//new tinyxml2::XMLText(pValue);
            tmpNode->LinkEndChild(content);
        }   
    }

    // save file and free doc
    if (doc)
    {
        doc->SaveFile(UserDefault::getInstance()->getXMLFilePath().c_str());
        delete doc;
    }
}

/**
 * implements of UserDefault
 */

UserDefault* UserDefault::_userDefault = nullptr;
string UserDefault::_filePath = string("");
bool UserDefault::_isFilePathInitialized = false;

UserDefault::~UserDefault()
{
}

UserDefault::UserDefault()
{
}

bool UserDefault::getBoolForKey(const char* pKey)
{
 return getBoolForKey(pKey, false);
}

bool UserDefault::getBoolForKey(const char* pKey, bool defaultValue)
{
    const char* value = nullptr;
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    node =  getXMLNodeForKey(pKey, &rootNode, &doc);
    // find the node
    if (node && node->FirstChild())
    {
        value = (const char*)(node->FirstChild()->Value());
    }

    bool ret = defaultValue;

    if (value)
    {
        ret = (! strcmp(value, "true"));
    }

    if (doc) delete doc;

    return ret;
}

int UserDefault::getIntegerForKey(const char* pKey)
{
    return getIntegerForKey(pKey, 0);
}

int UserDefault::getIntegerForKey(const char* pKey, int defaultValue)
{
    const char* value = nullptr;
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    node =  getXMLNodeForKey(pKey, &rootNode, &doc);
    // find the node
    if (node && node->FirstChild())
    {
        value = (const char*)(node->FirstChild()->Value());
    }

    int ret = defaultValue;

    if (value)
    {
        ret = atoi(value);
    }

    if(doc)
    {
        delete doc;
    }


    return ret;
}

float UserDefault::getFloatForKey(const char* pKey)
{
    return getFloatForKey(pKey, 0.0f);
}

float UserDefault::getFloatForKey(const char* pKey, float defaultValue)
{
    float ret = (float)getDoubleForKey(pKey, (double)defaultValue);

    return ret;
}

double  UserDefault::getDoubleForKey(const char* pKey)
{
    return getDoubleForKey(pKey, 0.0);
}

double UserDefault::getDoubleForKey(const char* pKey, double defaultValue)
{
    const char* value = nullptr;
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    node =  getXMLNodeForKey(pKey, &rootNode, &doc);
    // find the node
    if (node && node->FirstChild())
    {
        value = (const char*)(node->FirstChild()->Value());
    }

    double ret = defaultValue;

    if (value)
    {
        ret = utils::atof(value);
    }

    if (doc) delete doc;

    return ret;
}

std::string UserDefault::getStringForKey(const char* pKey)
{
    return getStringForKey(pKey, "");
}

string UserDefault::getStringForKey(const char* pKey, const std::string & defaultValue)
{
    const char* value = nullptr;
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    node =  getXMLNodeForKey(pKey, &rootNode, &doc);
    // find the node
    if (node && node->FirstChild())
    {
        value = (const char*)(node->FirstChild()->Value());
    }

    string ret = defaultValue;

    if (value)
    {
        ret = string(value);
    }

    if (doc) delete doc;

    return ret;
}

Data UserDefault::getDataForKey(const char* pKey)
{
    return getDataForKey(pKey, Data::Null);
}

Data UserDefault::getDataForKey(const char* pKey, const Data& defaultValue)
{
    const char* encodedData = nullptr;
    tinyxml2::XMLElement* rootNode;
    tinyxml2::XMLDocument* doc;
    tinyxml2::XMLElement* node;
    node =  getXMLNodeForKey(pKey, &rootNode, &doc);
    // find the node
    if (node && node->FirstChild())
    {
        encodedData = (const char*)(node->FirstChild()->Value());
    }

    Data ret = defaultValue;

    if (encodedData)
    {
        unsigned char * decodedData = nullptr;
        int decodedDataLen = base64Decode((unsigned char*)encodedData, (unsigned int)strlen(encodedData), &decodedData);

        if (decodedData) {
            ret.fastSet(decodedData, decodedDataLen);
        }
    }

    if (doc) delete doc;

    return ret;    
}


void UserDefault::setBoolForKey(const char* pKey, bool value)
{
    // save bool value as string

    if (true == value)
    {
        setStringForKey(pKey, "true");
    }
    else
    {
        setStringForKey(pKey, "false");
    }
}

void UserDefault::setIntegerForKey(const char* pKey, int value)
{
    // check key
    if (! pKey)
    {
        return;
    }

    // format the value
    char tmp[50];
    memset(tmp, 0, 50);
    sprintf(tmp, "%d", value);

    setValueForKey(pKey, tmp);
}

void UserDefault::setFloatForKey(const char* pKey, float value)
{
    setDoubleForKey(pKey, value);
}

void UserDefault::setDoubleForKey(const char* pKey, double value)
{
    // check key
    if (! pKey)
    {
        return;
    }

    // format the value
    char tmp[50];
    memset(tmp, 0, 50);
    sprintf(tmp, "%f", value);

    setValueForKey(pKey, tmp);
}

void UserDefault::setStringForKey(const char* pKey, const std::string & value)
{
    // check key
    if (! pKey)
    {
        return;
    }

    setValueForKey(pKey, value.c_str());
}

void UserDefault::setDataForKey(const char* pKey, const Data& value) {
    // check key
    if (! pKey)
    {
        return;
    }

    char *encodedData = 0;

    base64Encode(value.getBytes(), static_cast<unsigned int>(value.getSize()), &encodedData);

    setValueForKey(pKey, encodedData);

    if (encodedData)
        free(encodedData);
}

UserDefault* UserDefault::getInstance()
{
    initXMLFilePath();

    // only create xml file one time
    // the file exists after the program exit
    if ((! isXMLFileExist()) && (! createXMLFile()))
    {
        return nullptr;
    }

    if (! _userDefault)
    {
        _userDefault = new UserDefault();
    }

    return _userDefault;
}

void UserDefault::destroyInstance()
{
    CC_SAFE_DELETE(_userDefault);
}

// XXX: deprecated
UserDefault* UserDefault::sharedUserDefault()
{
    return UserDefault::getInstance();
}

// XXX: deprecated
void UserDefault::purgeSharedUserDefault()
{
    return UserDefault::destroyInstance();
}

bool UserDefault::isXMLFileExist()
{
    FILE *fp = fopen(_filePath.c_str(), "r");
    bool bRet = false;

    if (fp)
    {
        bRet = true;
        fclose(fp);
    }

    return bRet;
}
std::string UserDefault::GetValueForKeyPlist(std::string key){
    return "test";
}
void UserDefault::initXMLFilePath()
{
    if (! _isFilePathInitialized)
    {
        _filePath += FileUtils::getInstance()->getWritablePath() + XML_FILE_NAME;
        _isFilePathInitialized = true;
    }    
}

// create new xml file
bool UserDefault::createXMLFile()
{
    bool bRet = false;  
    tinyxml2::XMLDocument *pDoc = new tinyxml2::XMLDocument(); 
    if (nullptr==pDoc)  
    {  
        return false;  
    }  
    tinyxml2::XMLDeclaration *pDeclaration = pDoc->NewDeclaration(nullptr);  
    if (nullptr==pDeclaration)  
    {  
        return false;  
    }  
    pDoc->LinkEndChild(pDeclaration); 
    tinyxml2::XMLElement *pRootEle = pDoc->NewElement(USERDEFAULT_ROOT_NAME);  
    if (nullptr==pRootEle)  
    {  
        return false;  
    }  
    pDoc->LinkEndChild(pRootEle);  
    bRet = tinyxml2::XML_SUCCESS == pDoc->SaveFile(_filePath.c_str());

    if(pDoc)
    {
        delete pDoc;
    }

    return bRet;
}

const string& UserDefault::getXMLFilePath()
{
    return _filePath;
}

void UserDefault::flush()
{
}

NS_CC_END

#endif // (CC_TARGET_PLATFORM != CC_PLATFORM_IOS && CC_PLATFORM != CC_PLATFORM_ANDROID)

end here are some calls I make:

std::string textid = itemname + "_name";
std::string word = UserDefault::getInstance()->GetValueForKeyPlist(textid );
std::string word = UserDefault::getInstance()->GetValueForKeyPlist(node.child( "desc" ).attribute( "value" ).as_string());
std::string word = UserDefault::getInstance()->GetValueForKeyPlist(itemname+"_desc");

at each of this lines I get undefined reference to 'cocos2d::UserDefault::GetValueForKeyPlist(std::string)'

my cocos2dx game structure of code is like this

/MYGAME/Classes
/MYGAME/cocos2d/cocos
/MYGAME/ml

I have an android.mk file in the jni folder and in the /MYGAME/cocos2d/cocos, maybe it's a linkin problem, but if it was a linking problem why I don't get undefined reference when calling other functions from UserDefault's class.

Edit:Problem solved. There was an IF in the top of the class so this class would compile only on IOS Platform. now my method works.

Answer 1

If the code of this class is in your project, it means there is a declaration but no definition of cocos2d::UserDefault::GetValueForKeyPlist.

Maybe the declaration and definition differ in some way. they have to have the same return type and have to accept the same arguments. Both have to be const or not const etc.

If the code of this class is in a library, you have to link the library to your executable project in order to let it find the definition in the library.