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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>
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());
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>
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);
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 }
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