How do I make a GUI?

Question

I've made many different seperate parts of a GUI system for the Nintendo DS, like buttons and textboxes and select boxes, but I need a way of containing these classes in one Gui class, so that I can draw everything to the screen all at once, and check all the buttons at once to check if any are being pressed. My question is what is the best way organize all the classes (such as buttons and textboxes) into one GUI class?

Here's one way I thought of but it doesn't seem right:

Edit: I'm using C++.

class Gui {
    public:
        void update_all();
        void draw_all() const;
        int add_button(Button *button); // Returns button id
        void remove_button(int button_id);
    private:
        Button *buttons[10];
        int num_buttons;
}

This code has a few problems, but I just wanted to give you an idea of what I want.

Answer 1

This question is very similar to one I was going to post, only mine is for Sony PSP programming.

I've been toying with something for a while, I've consulted some books and VTMs, and so far this is a rough idea of a simple ui systems.

class uiElement()
{
    ...
    virtual void Update() = 0;
    virtual void Draw() = 0;
    ...
}

class uiButton() public : uiElement
{
    ...
    virtual void Update();
    virtual void Draw();
    ...
}

class uiTextbox() public : uiElement
{
    ...
    virtual void Update();
    virtual void Draw();
    ...
}

... // Other ui Elements

class uiWindow()
{
    ...
    void Update();
    void Draw();

    void AddElement(uiElement *Element);
    void RemoveElement(uiElement *Element);

    std::list <uiElement*> Elements;

    ...
}

void uiWindow::Update()
{
    ...
    for (list <uiElement*>::iterator it = Elements.begin(); it != Elements.end(); it++ )
        it->Update();
    ...
}

void uiWindow::Draw()
{
    ...
    for (list <uiElement*>::iterator it = Elements.begin(); it != Elements.end(); it++ )
        it->Draw();
    ...
}

The princple is to create a window and attact ui Elements to it, and call the draw and update methods from the respective main functions.

I don't have anything working yet, as I have issues with drawing code. With different APIs on the PC and PSP, I'm looking at some wrapper code for OpenGL and psp gu.

Hope this helps.

thing2k