Question

我试图从类View中的方法调用静态函数AreaMap :: staticInitialize（Model *）。它在我首先定义类AreaMap时进行编译，但是当我尝试首先声明View时，即使我转发声明的AreaMap，我也会得到错误。有人知道如何将View的定义保持在最顶层吗？

#ifndef VIEW_H
#define VIEW_H
#include "Model.h"

class AreaMap;

class View {
 public:
  void linkMvc(Model * m) {
    model = m;
    AreaMap::staticInitialize(m);
  }

  Model * model;
};

class AreaMap {
 public:
  void static staticInitialize(Model * m) {
    model = m;
  }
  Model * model;

};
#endif

错误：

inc/View.hpp: In member function ‘void View::linkMvc(Model*, Controller*)’:
inc/View.hpp:36:7: error: incomplete type ‘AreaMap’ used in nested name specifier
       AreaMap::staticInitialize(m);

Answer 1

#ifndef VIEW_H
#define VIEW_H

class AreaMap;

class View {
 public:
  void linkMvc(Model * m);

  Model * model;
};

class AreaMap {
 public:
  void static staticInitialize(Model * m) {
    model = m;
  }
  Model * model;

};

void View::linkMvc(Model * m) {
  model = m;
  AreaMap::staticInitialize(m);
}

#endif

然而，这仍然不应该编译。 staticInitialize()尝试修改非静态成员变量。

Answer 2

class AreaMap;                       <----- This won't suffice.

class View {
 public:
  void linkMvc(Model * m) {          <----- What's Model?
    model = m;
    AreaMap::staticInitialize(m);    <----- What's this?
  }

  Model * model;
};

这里有两个问题：

什么是Model？你应该向前宣布它。
您对课程AreaMap的前瞻声明不足以致电AreaMap::staticInitialize。您需要在引用之前声明该函数。

不同类中的静态类函数

2 个答案: