Cocos2d-x3.1UserDefaule类具体解释

在Cocos2d-x存储数据使用的类是UserDefault类，以下分析下该类的使用

//.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
     */
    const static std::string& getXMLFilePath();
    /**
     * @js NA
     */
    static bool isXMLFileExist();

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

使用时在自己定义类的.cpp文件里加入UserDefault.h，使用离子例如以下：

//.cpp
#include "base/CCUserDefault.h


UserDefault::getInstance()->setStringForKey("key", "value");
    auto value = UserDefault::getInstance()->getStringForKey("key","Default value");
    log("key = %s",value.c_str());

执行结果例如以下图：控制台打印出 key = value；