SbEventHandler< ArgType > Class Template Reference
[Basics]

Class representing an event. More...

#include <Inventor/SbEventHandler.h>

List of all members.

Public Member Functions
void	operator() (ArgType arg)
void	add (void(*f)(ArgType))
template<typename ClassType >
void	add (ClassType &a, void(ClassType::*f)(ArgType))
bool	remove (void(*f)(ArgType))
template<typename ClassType >
bool	remove (ClassType &a, void(ClassType::*f)(ArgType))

---

Detailed Description

template<typename ArgType>
class SbEventHandler< ArgType >

Class representing an event.

An SbEventHandler encapsulates a list of "callbacks" or "delegates" that will be called when an event occurs. We generally think of events as input events, like mouseMove or keyboard, but they can be anything, like starting a computation or notifying that an object's state has changed.

The callback signature must be:

void callback(EventArg arg)
where EventArg is the template type of SbEventHandler.

All SbEventHandler callbacks must return void and have a single argument of type EventArg . This argument will generally be a structure containing information about the event and possibly methods to query additional information. In OpenInventor, all EventArg will inherit from the SbEventArg class, but it is not mandatory if you want to define your own events. In any case, EventArg must not be void

Callbacks are registered using one of the add() methods. You can register a free function, a static class method or a member class method.

EXAMPLE

 // a free function
 void freeFunction(int arg) { }

 // Some class
 class MyClass {
 public:
   // a member function
   void memberFunction(int arg) { }
   // a static function
   static void staticFunction(int arg) { }
 };

 // event raised when something occurs. Prototype of callback should be void callback(int arg);
 SbEventHandler<int> onSomth;

 // To register a free or a static function, simply add it to EventHandler:
 onSomth.add(freeFunction);
 onSomth.add(MyClass::staticFunction);

 // Registering a member function is a little bit more complicated.
 // You need to specified the instance of class and a pointer to member function.
 // WARNING: The EventHandler will keep a reference on given instance. Be careful concerning lifetime
 // or this instance. If you want to delete it, don't forget to remove this callback front EventHandler
 // before deleting your instance.
 MyClass myInstance;
 onSomth.add(myInstance, &MyClass::memberFunction);

 // Raise the event. This will call all the registered callback with given argument. Here, "12".
 onSomth(12);

 // Unregister callback
 onSomth.remove(freeFunction);
 onSomth.remove(MyClass::staticFunction);
 onSomth.remove(myInstance, &MyClass::memberFunction);

Warning: All registered callbacks will be called exactly once, but the order is undefined.

SEE ALSO

SbEventArg

See related examples:

EventhandlerExample

---

Member Function Documentation

template<typename ArgType>

template<typename ClassType >

void SbEventHandler< ArgType >::add	(	ClassType &	a,
		void(ClassType::*)(ArgType)	f
	)			[inline]

Add a member function callback for this event.

template<typename ArgType>

void SbEventHandler< ArgType >::add

(

void(*)(ArgType)

f

)

[inline]

Add a static function callback for this event.

template<typename ArgType>

void SbEventHandler< ArgType >::operator()

(

ArgType

arg

)

[inline]

Call all registered callbacks.

Parameters:

arg

Argument that will be given to callback.

Warning:

Calling order of callbacks is undefined.

template<typename ArgType>

template<typename ClassType >

bool SbEventHandler< ArgType >::remove	(	ClassType &	a,
		void(ClassType::*)(ArgType)	f
	)			[inline]

Remove a member function.

If you add the same callback several times, you must remove it several times.

Returns:

True if callback has been removed.

template<typename ArgType>

bool SbEventHandler< ArgType >::remove

(

void(*)(ArgType)

f

)

[inline]

Remove a static function.

If you add the same callback several times, you must remove it several times.

Returns:

True if callback has been removed.

---

The documentation for this class was generated from the following file:

• Inventor/SbEventHandler.h