无需复制即可置入向量

Question

I have a vector of non-copyable objects and I need to use emplace_back() to add to the vector. Obviously that gets a error that its trying to reference a deleted function because it is non-copyable. I was just wondering, is there even a way to do this? I am more specifically trying to have a vector of sfml's render windows.

My Main

int main()
{
    sf::RenderWindow window(sf::VideoMode(100, 100, 32), "Main Window", sf::Style::Default);
    MakeKey MakeKey;
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            //Key Presses
            if (event.type == sf::Event::KeyPressed) {
                if (event.key.code == sf::Keyboard::A)
                    MakeKey.DrawKey("A");
                else if (event.key.code == sf::Keyboard::D)
                    MakeKey.DrawKey("D");
                //Ect
            }
            if (event.type == sf::Event::Closed)
                window.close();
        }
        MakeKey.StepWindows();
    }
    return EXIT_SUCCESS;
}

My DrawKey Function

void MakeKey::DrawKey(string input)
{
    MakeKey::NewKey Key;
    if (input == "A")
        Key.Img.loadFromFile("Assets/Images/A.png");
    else if (input == "D")
        Key.Img.loadFromFile("Assets/Images/D.png");
    //Ect
    sf::RenderWindow window(sf::VideoMode(Key.Img.getSize().x, Key.Img.getSize().y, 32), "Key", sf::Style::None);
    Key.Tex.loadFromImage(Key.Img);
    Key.Sprite.setTexture(Key.Tex);
    KeyArray.emplace_back(std::move(Key));
    WindowArray.push_back(std::move(window));
    cout << "KeyArray Has " << KeyArray.size() << " Elements\n" << "WindowArray Has " << WindowArray.size() << " Elements" << endl;
}

My StepWindows Function

void MakeKey::StepWindows()
{
    for (int i{ 0 }; i > KeyArray.size(); i++)
    {
        cout << "Inside Step Windows For Loop" << endl;
        WindowArray[1].setActive(true);
        WindowArray[1].clear(sf::Color::Transparent);
        WindowArray[1].draw(KeyArray[1].Sprite);
        WindowArray[1].display();
    }
}

Answer 1

To use either std::vector<T>::push_back() or std::vector<T>::emplacy_back() The type T is required to have either a copy constructor or a noexcept move constructor. Please pay special attention that the requirement for the move constructor to be noexcept is important: that allows to keep exception safity while the buffer reallocation.