CODEWITHSUNDEEP
c++functionpointersbuttonsfml
Wigrys
Wigrys

Reputation: 1

C++, SFML - Buttons: how to make button that store pointer to method of other class?

I am trying to make a little pong game with menu. So I`ve made a Button class, that stores function which i run when button gets clicked. This is how i try to set function that have to get invoked when i press button. (setOnClickFunction)

void MenuState::initializeButtons()
{
    Button* startButton = new Button({ 200.f, 200.f }, { 100.f, 100.f },
        "startButton");
    startButton->setOnClickFunction(startButtonOnClick);
}

void MenuState::startGameButtonOnClick()
{
    std::cout << "startButton\n";
}

... and this is how my Button class looks like:

class Button : public Drawable, public Transformable
{
protected:
    void  (*onClick)();
public:
    void isClicked(Vector2i mousePos);
    void setOnClickFunction(void (*function)());
};

after that i get error: 

"error C3867: 'MenuState::startGameButtonOnClick': non-standard syntax; use '&' to create a pointer to member"

//EDIT

This is the code that solved my problem: //MenuState:

void MenuState::initializeButtons()
{
    Button* startButton = new Button({ 200.f, 200.f }, { 100.f, 100.f },
        "startButton");
    startButton->setOnClickFunction(std::bind(&MenuState::startGameButtonOnClick, this));
}

//Button class:

class Button : public Drawable, public Transformable
{
protected:
    std::function<void()> onClick;
public:
    void isClicked(Vector2i mousePos);
    void setOnClickFunction(std::function<void()> function);
};

Upvotes: 0

Views: 773

Answers (1)

wreckgar23
wreckgar23

Reputation: 1045

Just use std::function to store your click function. There are plenty of examples here

Also, have a look at std::unique_ptr to store your button within your MenuState

Upvotes: 1

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