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cocos2d-x中几种存储数据的方式

说明:本文所论述内容均基于cocos2dx 3.0 版本。

1、UserDefault

它是cocos2d-x用来存取基本数据类型用的。保存为XML文件格式。

查看CCUserDefault文件,可以看出,文件名默认为UserDefault.xml。在win32平台,Debug下,该文件在Debug.win32文件夹内。如果该文件不存在,则会创建新文件。

1 // root name of xml2 #define USERDEFAULT_ROOT_NAME    "userDefaultRoot"3 4 #define XML_FILE_NAME "UserDefault.xml"

用UserDefault

操作方式比较简单:

主要方法:(和java的map很像,键值对,应该很容易懂的)

1 void    setBoolForKey(const char* pKey, bool value);2 void    setIntegerForKey(const char* pKey, int value);3 void    setFloatForKey(const char* pKey, float value);4 void    setDoubleForKey(const char* pKey, double value);5 void    setStringForKey(const char* pKey, const std::string & value);

通过键读取数据,如果键不存在,可以设置一个defaultValue返回自己想要的值。

1 bool    getBoolForKey(const char* pKey, bool defaultValue = http://www.mamicode.com/false);2 int    getIntegerForKey(const char* pKey, int defaultValue = http://www.mamicode.com/0);3 float    getFloatForKey(const char* pKey, float defaultValue=http://www.mamicode.com/0.0f);4 double    getDoubleForKey(const char* pKey, double defaultValue=http://www.mamicode.com/0.0);5 std::string    getStringForKey(const char* pKey, const std::string & defaultValue = http://www.mamicode.com/"");

UserDefault封装了对XML文件的处理,提供了简单操作文件的方法,但是不足之处在于固定的文件夹,固定的文件名称。有限的数据类型。

2、FileUtils

 static FileUtils* getInstance();//获取FileUtils类的实例   

在cocos2d-x中,文件读写其实直接使用c/c++中的文件读写操作方法,但是,在实际运用中,由于移动客户端读写文件需要相应的权限,所以读写文件就需要先指定文件的路径,我们不需要获取绝对路径,只需要获取相对路径就行,因为cocos2d-x底层已经做了相应各个平台的处理.

std::string fullPathForFilename(const std::string &filename);//获取文件的完整路径  

std::string getStringFromFile(const std::string& filename);//读取文件中的字符串

Data getDataFromFile(const std::string& filename);//获取文件数据 

可以看下Data类:

 1 class CC_DLL Data 2 { 3 public: 4     static const Data Null; 5     //构造函数 6     Data(); 7     Data(const Data& other); 8     Data(Data&& other); 9     ~Data();10     // 重载符号11     Data& operator= (const Data& other);12     Data& operator= (Data&& other);13 14     unsigned char* getBytes() const;//获取数据15     ssize_t getSize() const;//尺寸16     void copy(unsigned char* bytes, const ssize_t size);//从bytes复制17     void fastSet(unsigned char* bytes, const ssize_t size);//从bytes快速set,使用后bytes将不能在外部使用18     void clear();//清除19     bool isNull() const;//判空20 private:21     void move(Data& other);22 private:23     unsigned char* _bytes;24     ssize_t _size;25 };

unsigned char* getFileDataFromZip(const std::string& zipFilePath, const std::string& filename, ssize_t *size);//读取压缩文件数据(zip格式)

如果读取成功size中会返回文件的大小,否则返回0。

如果我们通过setSearchPaths()设置搜索路径("/mnt/sdcard/", "internal_dir/"),然后通过setSearchResolutionsOrder()设置子区分路径("resources-ipadhd/", "resources-ipad/", "resources-iphonehd")。如果搜索文件名为‘sprite.png‘ 那么会先在文件查找字典中查找key: sprite.png -> value: sprite.pvr.gz,然后搜索文件‘sprite.pvr.gz‘如下顺序:

1              /mnt/sdcard/resources-ipadhd/sprite.pvr.gz      (if not found, search next)2              /mnt/sdcard/resources-ipad/sprite.pvr.gz        (if not found, search next)3              /mnt/sdcard/resources-iphonehd/sprite.pvr.gz    (if not found, search next)4              /mnt/sdcard/sprite.pvr.gz                       (if not found, search next)5              internal_dir/resources-ipadhd/sprite.pvr.gz     (if not found, search next)6              internal_dir/resources-ipad/sprite.pvr.gz       (if not found, search next)7              internal_dir/resources-iphonehd/sprite.pvr.gz   (if not found, search next)8              internal_dir/sprite.pvr.gz                      (if not found, return "sprite.png")

If the filename contains relative path like "gamescene/uilayer/sprite.png",
and the mapping in fileLookup dictionary contains `key: gamescene/uilayer/sprite.png -> value: gamescene/uilayer/sprite.pvr.gz`.
The file search order will be:

/mnt/sdcard/gamescene/uilayer/resources-ipadhd/sprite.pvr.gz (if not found, search next)
/mnt/sdcard/gamescene/uilayer/resources-ipad/sprite.pvr.gz (if not found, search next)
/mnt/sdcard/gamescene/uilayer/resources-iphonehd/sprite.pvr.gz (if not found, search next)
/mnt/sdcard/gamescene/uilayer/sprite.pvr.gz (if not found, search next)
internal_dir/gamescene/uilayer/resources-ipadhd/sprite.pvr.gz (if not found, search next)
internal_dir/gamescene/uilayer/resources-ipad/sprite.pvr.gz (if not found, search next)
internal_dir/gamescene/uilayer/resources-iphonehd/sprite.pvr.gz (if not found, search next)
internal_dir/gamescene/uilayer/sprite.pvr.gz (if not found, return "gamescene/uilayer/sprite.png")

If the new file can‘t be found on the file system, it will return the parameter filename directly.

如果找到返回完整路径,没找到返回‘sprite.png‘。

void loadFilenameLookupDictionaryFromFile(const std::string &filename);//从文件导入文件名查找字典

文件为plist格式如下:

 1    /** 2      * Loads the filenameLookup dictionary from the contents of a filename. 3      *  4      * @note The plist file name should follow the format below: 5      *  6      * @code 7      * <?xml version="1.0" encoding="UTF-8"?> 8      * <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> 9      * <plist version="1.0">10      * <dict>11      *     <key>filenames</key>12      *     <dict>13      *         <key>sounds/click.wav</key>14      *         <string>sounds/click.caf</string>15      *         <key>sounds/endgame.wav</key>16      *         <string>sounds/endgame.caf</string>17      *         <key>sounds/gem-0.wav</key>18      *         <string>sounds/gem-0.caf</string>19      *     </dict>20      *     <key>metadata</key>21      *     <dict>22      *         <key>version</key>23      *         <integer>1</integer>24      *     </dict>25      * </dict>26      * </plist>27      * @endcode28      * @param filename The plist file name.29      *30      @since v2.131      * @js loadFilenameLookup32      * @lua loadFilenameLookup33      */

void setFilenameLookupDictionary(const ValueMap& filenameLookupDict);//从ValueMap中设置文件名查找字典

ValueMap的定义:

 1 typedef std::unordered_map<std::string, Value> ValueMap; 

std::string fullPathFromRelativeFile(const std::string &filename, const std::string &relativeFile);//获取相对应文件的完整路径 

 e.g. filename: hello.png, pszRelativeFile: /User/path1/path2/hello.plist   Return: /User/path1/path2/hello.pvr (If there a a key(hello.png)-value(hello.pvr) in FilenameLookup dictionary. )

 void setSearchResolutionsOrder(const std::vector<std::string>& searchResolutionsOrder);//设置子搜索区分路径

见fullPathForFilename()。

void addSearchResolutionsOrder(const std::string &order);//增加子搜索路径

const std::vector<std::string>& getSearchResolutionsOrder();//获取子搜索区分路径

void setSearchPaths(const std::vector<std::string>& searchPaths);//设置搜索路径

见fullPathForFilename()。

void addSearchPath(const std::string & path);//增加搜索路径

const std::vector<std::string>& getSearchPaths() const;//获取搜索路径

 std::string getWritablePath();//获取一个可写入文件的路径

经过测试在win32平台上,debug版本返回的是程序文件所在的路径,release返回的是“我的文档”路径。

bool isFileExist(const std::string& filePath);//判断文件是否存在

经过测试在win32平台上,如果路径中包含中文字符会找不到文件。所以可以自己写个。

bool isAbsolutePath(const std::string& path);判断是否为绝对路径

 

void setPopupNotify(bool notify);

bool isPopupNotify();

Sets/Gets 当文件加载失败时弹出messagebox.

 

ValueMap getValueMapFromFile(const std::string& filename);//从文件获取ValueMap

bool writeToFile(ValueMap& dict, const std::string& fullPath);//写入一个ValueMap数据到plist格式文件

ValueVector getValueVectorFromFile(const std::string& filename);//从文件获取ValueVector

ValueVector定义:

 1 typedef std::vector<Value> ValueVector; 

函数也就这些了,还没有写demo代码,写好了贴过来。

 

 3.SQLite

4、plist文件读写

在cocos2d-x中,对于plist文件,既可以读取,也可以进行写入的操作;下面先来看一个plist文件:

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"/> 3  4 <plist version="1.0"> 5     <dict> 6         <key>string element key</key> 7         <string>string element value</string> 8         <key>array</key> 9         <array>10             <dict>11                 <key>string in dictInArray key 0</key>12                 <string>string in dictInArray value 0</string>13                 <key>string in dictInArray key 1</key>14                 <string>string in dictInArray value 1</string>15             </dict>16             <string>string in array</string>17             <array>18                 <string>string 0 in arrayInArray</string>19                 <string>string 1 in arrayInArray</string>20             </array>21         </array>22         <key>dictInDict, Hello World</key>23         <dict>24             <key>string in dictInDict key</key>25             <string>string in dictInDict value</string>26             <key>bool</key>27             <true/>28             <key>integer</key>29             <integer>1024</integer>30             <key>float</key>31             <real>1024.1024170</real>32             <key>double</key>33             <real>1024.1230000000000000</real>34         </dict>35     </dict>36 </plist>
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先不看上面的plist文件到底有些什么内容;实际上它是由下一段代码生成的。

 1 auto root = Dictionary::create(); 2     auto string = String::create("string element value"); 3     root->setObject(string, "string element key"); // 添加一个键值对 4      5     auto array = Array::create();  // 创建一个array 6      7     auto dictInArray = Dictionary::create(); 8     dictInArray->setObject(String::create("string in dictInArray value 0"), "string in dictInArray key 0"); 9     dictInArray->setObject(String::create("string in dictInArray value 1"), "string in dictInArray key 1");10     array->addObject(dictInArray); // 往数组中添加一个键值对11     12     array->addObject(String::create("string in array")); // 往数组中添加一个字符串13     14     auto arrayInArray = Array::create();15     arrayInArray->addObject(String::create("string 0 in arrayInArray"));16     arrayInArray->addObject(String::create("string 1 in arrayInArray"));17     array->addObject(arrayInArray); // 往数组中添加一个数组18     19     root->setObject(array, "array");20     21     auto dictInDict = Dictionary::create();22     dictInDict->setObject(String::create("string in dictInDict value"), "string in dictInDict key");23    24     //add boolean to the plist25     auto booleanObject = Bool::create(true);26     dictInDict->setObject(booleanObject, "bool");27     28     //add interger to the plist29     auto intObject = Integer::create(1024);30     dictInDict->setObject(intObject, "integer");31     32     //add float to the plist33     auto floatObject = Float::create(1024.1024f);34     dictInDict->setObject(floatObject, "float");35     36     //add double to the plist37     auto doubleObject = Double::create(1024.123);38     dictInDict->setObject(doubleObject, "double");39     40     root->setObject(dictInDict, "dictInDict, Hello World");41 // end with /42     std::string writablePath = FileUtils::getInstance()->getWritablePath();43     std::string fullPath = writablePath + "text.plist";44     if(root->writeToFile(fullPath.c_str()))45         log("see the plist file at %s", fullPath.c_str());46     else47         log("write plist file failed");48     49     // 读取上面创建的内容50     auto loadDict = __Dictionary::createWithContentsOfFile(fullPath.c_str());51     auto loadDictInDict = (__Dictionary*)loadDict->objectForKey("dictInDict, Hello World");52     auto boolValue = http://www.mamicode.com/(__String*)loadDictInDict->objectForKey("bool");53     CCLOG("%s",boolValue->getCString());54     auto floatValue = http://www.mamicode.com/(__String*)loadDictInDict->objectForKey("float");55     CCLOG("%s",floatValue->getCString());56     auto intValue = http://www.mamicode.com/(__String*)loadDictInDict->objectForKey("integer");57     CCLOG("%s",intValue->getCString());58     auto doubleValue = http://www.mamicode.com/(__String*)loadDictInDict->objectForKey("double");59     CCLOG("%s",doubleValue->getCString());
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因此可以看出,对符合一定格式的plist文件,可以通过Dictionary进行操作。cocos2dx 3.0 的Dictionary,可以实现对Array,Dictionary,Integer,String,Bool等基础数据类型进行读写。

下面再来看另一种读取方式: 假定plist文件如下;

1 <plist version="1.0">2 <dict>3     <key>name</key>4     <string>Ls</string>5     <key>isgirl</key>6     <false/>7 </dict>8 </plist>
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读取方式二,这种方法是借助VectorMap来进行读的:

1  FileUtils * fu = FileUtils::getInstance();2     ValueMap vm = fu->getValueMapFromFile("Info.plist");3     log("%s", vm["name"].asString().c_str()); // 读取string -->Ls4     bool bl = vm["isgirl"].asBool(); // 读取bool -->05     log("%d", bl);
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如果文件节点也是一个ValueMap,则可以通过xm["xx"].asValueMap()将节点转换为ValueMap;如果根节点为数组也可能直接通过ValueVector.getValueVectorFromFile("xx")读取数据;

5、xml文件读取

 1 FileUtils * fu = FileUtils::getInstance(); 2     auto doc = new tinyxml2::XMLDocument(); 3     doc->Parse(fu->getStringFromFile("data.xml").c_str()); 4     auto root = doc->RootElement(); 5     for (auto e = root->FirstChildElement(); e; e = e->NextSiblingElement()) { 6         std::string str; 7         for (auto attr = e->FirstAttribute(); attr; attr = attr->Next()) { 8             str += attr->Name(); 9             str += ":";10             str += attr->Value();11             str += ",";12         }13         log("%s", str.c_str());14     }
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data.xml

1 <data>2     <p name="zs" age="23"/>3     <p name="ls" age="25"/>4 </data>

上面的代码输出内容为:

cocos2d: name:zs,age:23,
cocos2d: name:ls,age:25,

注:需要导入cosos2d-x库 <tinyxml2/tinyxml2.h>

6、JSON文件读取

先来看一个json  :  [{"name": "zs","age": 23}, {"name": "ls","age": 25}]

1  rapidjson::Document d;2     d.Parse<0>(fu->getStringFromFile("dj.json").c_str()); // 0表示默认的解析方式;3     log("%s", d[rapidjson::SizeType(0)]["name"].GetString());

注:需要导入cocos2d-x库  <json/document.h>

cocos2d-x中几种存储数据的方式