First I will present some code, then make a description of a problem:
class CGUIObject
{
protected:
int m_id;
bool m_bVisible;
// Other non-relevant fields and methods specific for gui object...
};
class CClickable
{
private:
bool m_bClicked;
public:
bool isClicked();
void setClicked(bool bClicked);
virtual bool wasClicked(const TPoint& clickPos) = 0;
// Other non-relevant fields and methods specific for clickable object...
};
class CComponent : public CGUIObject
{
// The only important part of this class is that it derives from CGUIObject
};
class CButton : public CComponent, CClickable
{
// The only important part of this class is that it derives from CComponent and CClickable
};
// Now there is a method in my EventManager which informs all clickables about left mouse click event
void CEventManager::lMouseButtonClickEvent(const CPoint& clickPos)
{
// Go through all clickables
for(unsigned int i = 0; i < m_clickableObjectsList.size(); i++)
{
TClickable* obj = m_clickableObjectsList[i];
// Here I would like to also check if obj is visible
if(obj->wasClicked(clickPos))
{
obj->setClicked(true);
if(obj->m_pOnClickListener != nullptr)
obj->m_pOnClickListener->onClick();
return; // Only one object can be clicked at once
}
}
}
Ok, so as you can see:
m_bVisible
field which is important for me Now I'd like to inform specific CClickable object which was clicked but ONLY if it's visible. I know that all clickables also derive from CGUIObject (eg CButton), but it's a list of CClickable* so it's understandable I can't get access to m_bVisible
field. I know it simply shows I've made a mistake in designing, but is there way to resolve this problem in some elegant and easy way?
If you know all clickables are derived from CGUIObject
, you can use a dynamic_cast
:
CClickable* obj = m_clickableObjectsList[i];
// Here I would like to also check if obj is visible
if(obj->wasClicked(clickPos) && dynamic_cast<CGUIObject*>(obj)->m_bVisible)
{
//...
If the clickable was not a GUI object, the dynamic_cast
would return a null pointer in such case, and you should check this before dereferencing the result.
Rather than using something like a dynamic_cast
, you have to implement the wasClicked
in CButton
to say if the button is invisible it was not clicked.
bool CButton::wasClicked() {
if(!m_bVisible) return false;
/*previous logic*/
}
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