如何在std :: vector中访问存储为指针的接口实现对象

Question

所以我有这个:

std::vector<EnemyInterface*> _activeEnemies;

EnemyInterface看起来像这样:

#include "Ogre.h"

class EnemyInterface{
public:
  virtual void update(const Ogre::Real deltaTime) = 0;
  virtual void takeDamage(const int amountOfDamage, const int typeOfDamage) = 0;
  virtual Ogre::Sphere getWorldBoundingSphere() const = 0;
  virtual ~EnemyInterface(){} 
};

我创造了一个新的敌人:

// Spikey implements EnemyInterface
activeEnemies.push_back( (EnemyInterface*) &Spikey(_sceneManager, Ogre::Vector3(8,0,0)) );

我想在每个敌人身上调用更新功能,但它崩溃了:

// update enemies
for (std::vector<EnemyInterface*>::iterator it=_activeEnemies.begin(); it!=_activeEnemies.end(); ++it){
        (**it).update(timeSinceLastFrame); // Option 1: access violation reading location 0xcccccccc
        (*it)->update(timeSinceLastFrame); // Option 2: access violation reading location0xcccccccc
    }

我可以在屏幕上看到敌人,但我无法访问它.任何帮助,将不胜感激.

Spikey.h看起来像这样:

#include "EnemyInterface.h"

class Spikey: virtual public EnemyInterface{
private:
int thisID;
static int ID;

Ogre::SceneNode* _node;
Ogre::Entity* _entity;
public:
Spikey(Ogre::SceneManager* sceneManager, const Ogre::Vector3 spawnPos);

// interface implementation
virtual void update(const Ogre::Real deltaTime);
virtual void takeDamage(const int amountOfDamage, const int typeOfDamage);
virtual Ogre::Sphere getWorldBoundingSphere() const;
};

Answer 1

这是因为你在通话中创建了一个临时对象push_back.一旦push_back函数返回该对象就不再存在,并为您留下悬空指针.

您必须使用以下方法创建新对象new:

activeEnemies.push_back(new Spikey(_sceneManager, Ogre::Vector3(8,0,0)));