Question

我最近开始使用C ++的模板功能。不幸的是，我认为我不太明白如何编写模板化类的实现。我有一个带有实现的模板化类，以及一个带有实现的子类的模板化类。编译器在几乎所有类的所有方法上都给出了2019个链接器错误 - 而且我很确定问题在于我实现模板化类的方式。当我查找这些错误时，大部分时间是在有人忘记实现他在标题中定义的方法时发生的，但我很确定这不是这里的情况。

我的代码如下：

//ResourceManager.h
#ifndef ResMan_H
#define ResMan_H

#include "Loader.h"
#include <iostream>
#include <map>
#include <string>

template<class Res>
class ResourceManager {

private:
    std::map<int, Res*> resourceList;
    Loader<Res> * loader;

public:
    ~ResourceManager();
    ResourceManager(Loader<Res> * loader);
    void load(int key, std::string filePath);
    Res* request(int key);
    void unload(int key);
    void dispose();
};

#endif

实现：

//ResourceManager.cpp
#include "ResourceManager.h"
#include <assert.h>

template<class Res>
ResourceManager<Res>::~ResourceManager(){
    this->dispose();
}

ResourceManager<class Res>::ResourceManager(Loader<Res> * loader){
    this->loader = loader;
}

void ResourceManager<class Res>::load(int key, std::string filePath){
    unload(key);
    this->resourceList[key] = this->loader->loadFromFile(filePath);
}

Res* ResourceManager<class Res>::request(int key){
    assert(this->resourceList.find(key) == this->resourceList.end() && "Resource could not be found. Make sure to load it before requesting it.");
    return this->resourceList[key];
}

template<class Res>
void ResourceManager<Res>::unload(int key){
    if (this->resourceList.find(key) != this->resourceList.end()){
        delete this->resourceList[key];
        this->resourceList.erase(key);
    }
}

void ResourceManager<class Res>::dispose(){
    for(std::pair<int, Res*> kv : resourceList){
        delete kv.second;
    }
    resourceList.clear();
}

Loader.h

#ifndef Loader_H
#define Loader_H

#include <iostream>

template<class Res>
class Loader {

public:
    virtual Res* loadFromFile(std::string filePath);

};

#endif

TextureLoader.h

#ifndef TextureLoader_H
#define TextureLoader_H

#include "Loader.h"
#include <SFML\Graphics.hpp>

class TextureLoader : public Loader<sf::Texture> {

public:
    sf::Texture* loadFromFile(std::string path);

};


#endif

实施

#include "TextureLoader.h"

sf::Texture* TextureLoader::loadFromFile(std::string path){
    sf::Texture* texture = new sf::Texture();
    texture->loadFromFile(path);
    std::cout << "Texture loaded" << std::endl;
    return texture;
}

对于长代码感到抱歉，但即使这些函数的主体不相关我也宁愿发帖，因为我不是100％错误不在于代码。

链接器错误LNK2019＆amp; LNK2001关于模板化类文件

0 个答案: