Compiler errors ‘NonCopyable::NonCopyable(const NonCopyable&)’ is private

My code won't compile. What am I doing wrong? I'd also like the sf::Window and sf::Input objects to be static fields. What's the best way to go about this?

#include <SFML/Window.hpp>
#include <SFML/Window/Event.hpp>
#ifndef WINDOW_INITIALIZER_H
#define WINDOW_INITIALIZER_H

class WindowInitializer
{
public:
    WindowInitializer();
    ~WindowInitializer();

private:
    void initialize_booleans(const sf::Window * const app);

    bool m_leftKeyPressed;
    bool m_rightKeyPressed;
    bool m_upKeyPressed;
    bool m_downKeyPressed;

    unsigned int m_mouseX;
    unsigned int m_mouseY;
};

#endif // WINDOWINITIALIZER_H

void WindowInitializer::initialize_booleans(const sf::Window* const app)
{

    sf::Input input = app->GetInput();

    this->m_downKeyPressed = input.IsKeyDown(sf::Key::Down);
    this->m_leftKeyPressed = input.IsKeyDown(sf::Key::Left);
    this->m_upKeyPressed = input.IsKeyDown(sf::Key::Up);
    this->m_rightKeyPressed = input.IsKeyDown(sf::Key::Right);

    this->m_mouseX = input.GetMouseX();
    this->m_mouseY = input.GetMouseY();
}

WindowInitializer::WindowInitializer()
{
    sf::Window app(sf::VideoMode(640, 480, 32), "SFML Tutorial");

    initialize_booleans(&app);

    sf::Event event;

    while(app.IsOpened())
    {
        while(app.GetEvent(event))
        {
            if (event.Type == sf::Event::Closed)
                app.Close();
            if ((event.Type == sf::Event::KeyPressed) && (event.Key.Code == sf::Key::Escape))
                app.Close();
            if (m_downKeyPressed)
                std::cout << "down key pressed!";
            else if(m_leftKeyPressed)
                std::cout << "left key pressed!";
            else if(m_upKeyPressed)
                std::cout << "up key pressed!";
            else if(m_rightKeyPressed)
                std::cout << "right key pressed!";
        }
    }

}

WindowInitializer::~WindowInitializer()
{
    delete m_app;
}

My errors are as follows:

In file included from /usr/include/SFML/Window.hpp:35:0,
                 from ../SFML_tutorial/window_initializer.cpp:3:
/usr/include/开发者_如何学GoSFML/System/NonCopyable.hpp: In copy constructor ‘sf::Input::Input(const sf::Input&)’:
/usr/include/SFML/System/NonCopyable.hpp:57:5: error: ‘sf::NonCopyable::NonCopyable(const sf::NonCopyable&)’ is private
/usr/include/SFML/Window/Input.hpp:45:1: error: within this context
../SFML_tutorial/window_initializer.cpp: In member function ‘void WindowInitializer::initialize_booleans(const sf::Window*)’:
../SFML_tutorial/window_initializer.cpp:9:37: note: synthesized method ‘sf::Input::Input(const sf::Input&)’ first required here 
../SFML_tutorial/window_initializer.cpp: In destructor ‘WindowInitializer::~WindowInitializer()’:
../SFML_tutorial/window_initializer.cpp:51:12: error: ‘m_app’ was not declared in this scope

The error message should be clear:

1. You can’t copy sf::Input. You need to use a reference.

     sf::Input& input = app->GetInput();
   

2. Your destructor is deleting an object that doesn’t exist. The variable was never declared.