cocos2d::Value是许多基本类型(int,float,double,bool,unsigned char,char*和std::string)还有std::vector<Value>,std::unordered_map<std::string,Value>和std::unordered_map<int,Value>这些类的包装类型。

你可以将上面提及的基本类放进cocos2d::Value对象将它们转换成对应的类型，反之亦然。

内存管理

注意：cocos2d::Value不能像其它cocos2d类型一样使用retain/release和引用计数内存管理

示例

Value val;   // call the default constructor
if (val.isNull()) {
    log("val is null");
}else{
    std::string str =val.getDescription();
    log("The description of val0:%s",str.c_str());
}
//----------------------------------------------------
Value val1(65);   // initialize with a integer
//Value val1(3.4f); // initialize with a float value
//Value val1(3.5); // initialize with a double value
log("The description of the integer value:%s",val1.getDescription().c_str());
log("val1.asByte() = %c",val1.asByte());
//----------------------------------------------------
std::string strV = "string";
Value val2(strV);   // initialize with string
log("The description of the string value:%s",val2.getDescription().c_str());
//----------------------------------------------------
auto sp0 = Sprite::create();
Vector<Object*>* vecV = new Vector<Object*>();
vecV->pushBack(sp0);
Value val3(vecV);   // initialize with Vector
log("The description of the Vector value:%s",val3.getDescription().c_str());
delete vecV;
//----------------------------------------------------
Map<std::string,Object*>* mapV = new Map<std::string,Object*>();
mapV->insert(strV,sp0);
Value val4(mapV);   // initialize with Map
log("The description of the Map value:%s",val4.getDescription().c_str());
delete mapV;
//----------------------------------------------------
Value val6(&val4);   // initialize with Map
log("The description of the Value-type value:%s",val6.getDescription().c_str());
//----------------------------------------------------
val2 = val1;   // assigning between 2 Value-type
log("operator-> The description of val2:%s",val2.getDescription().c_str());
val2 = 4;   //assigning directly
log("operator-> The description of val4:%s",val2.getDescription().c_str());

结果是：

cocos2d: val is null
cocos2d: The description of the integer value:
65

cocos2d: val1.asByte() = A
cocos2d: The description of the string value:
string

cocos2d: The description of the Vector value:
true

cocos2d: The description of the Map value:
true

cocos2d: The description of the Value-type value:
true

cocos2d: operator-> The description of val2:
65

cocos2d: operator-> The description of val4:
4

最佳用法

• 考虑使用cocos2d::Value和新的模版容器(cocos2d::Vector和cocos2d::Map)优于使用cocos2d::CCBool,cocos2d::CCFloat,cocos2d::CCDouble,cocos2d::CCString,cocos2d::CCInteger和旧的objective-c风格的容器(cocos2d::CCArray和cocos2d::CCDictionary)。

• 当要使用基本类型的聚合时，将基本类型包装成cocos2d::Value，然后将它们和模版容器cocos2d::Vector和cocos2d::Map联合使用。