Question

我试图创建一个简单的windows api。

我需要一些帮助来设置side class中的函数指针我试图将函数设置为类中的函数时遇到错误，无论如何这可以在不使用类中的静态的情况下完成吗？

class Window
{
public:
    WIN_API Window();

    struct WIN_API
    {
        bool(*OnMouseClick)(Vector2D position, MouseButton button);
        bool(*OnCreate)();
    }Event;
};

class MainWindow : public Window
{
public:
    MainWindow() : Window()
    {
        //error here
        this->Event.OnCreate = OnCreate;
        this->Event.OnMouseClick = OnMouseClick;
    }

    bool OnCreate()
    {
        return true;
    }

    bool OnMouseClick(Vector2D position, MouseButton button)
    {
        return true;
    }
};

Answer 1

您必须绑定特定实例的成员函数。最好使用lambda和std::function对象。

class Window
{
public:
    Window();

    struct WIN_API
    {
      std::function<bool(Vector2D, MouseButton)> OnMouseClick;
      std::function<bool()> OnCreate;
    } Event;
};

class MainWindow : public Window
{
public:
    MainWindow()
    {
      this->Event.OnCreate =
        [this] () { return this->OnCreate(); };

      this->Event.OnMouseClick =
        [this] (Vector2D position, MouseButton button)
        { return this->OnMouseClick(position, button); };
    }

    bool OnCreate()
    {
        return true;
    }

    bool OnMouseClick(Vector2D position, MouseButton button)
    {
        return true;
    }
};

在类中设置函数指针

1 个答案: