#include <juce_ListenerList.h>

Classes
struct	DummyBailOutChecker
struct	Iterator
class	WrappedIterator

Public Types
using	ThisType = ListenerList<ListenerClass, ArrayType>
using	ListenerType = ListenerClass

Public Member Functions
	ListenerList ()=default
	~ListenerList ()
void	add (ListenerClass *listenerToAdd)
void	remove (ListenerClass *listenerToRemove)
int	size () const noexcept
bool	isEmpty () const noexcept
void	clear ()
bool	contains (ListenerClass *listener) const noexcept
const ArrayType &	getListeners () const noexcept
template<typename Callback>
void	call (Callback &&callback)
template<typename Callback>
void	callExcluding (ListenerClass *listenerToExclude, Callback &&callback)
template<typename Callback, typename BailOutCheckerType>
void	callChecked (const BailOutCheckerType &bailOutChecker, Callback &&callback)
template<typename Callback, typename BailOutCheckerType>
void	callCheckedExcluding (ListenerClass *listenerToExclude, const BailOutCheckerType &bailOutChecker, Callback &&callback)
void	call (void(ListenerClass::*callbackFunction)())
void	callExcluding (ListenerClass listenerToExclude, void(ListenerClass::callbackFunction)())
template<class BailOutCheckerType>
void	callChecked (const BailOutCheckerType &bailOutChecker, void(ListenerClass::*callbackFunction)())
template<class BailOutCheckerType>
void	callCheckedExcluding (ListenerClass listenerToExclude, const BailOutCheckerType &bailOutChecker, void(ListenerClass::callbackFunction)())
template<typename... MethodArgs, typename... Args>
void	call (void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)
template<typename... MethodArgs, typename... Args>
void	callExcluding (ListenerClass listenerToExclude, void(ListenerClass::callbackFunction)(MethodArgs...), Args &&... args)
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>
void	callChecked (const BailOutCheckerType &bailOutChecker, void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>
void	callCheckedExcluding (ListenerClass listenerToExclude, const BailOutCheckerType &bailOutChecker, void(ListenerClass::callbackFunction)(MethodArgs...), Args &&... args)

Private Attributes
ArrayType	listeners
WrappedIterator *	activeIterators = nullptr

Detailed Description

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
class juce::ListenerList< ListenerClass, ArrayType >

Holds a set of objects and can invoke a member function callback on each object in the set with a single call.

Use a ListenerList to manage a set of objects which need a callback, and you can invoke a member function by simply calling call() or callChecked().

E.g.

class MyListenerType
{
public:
    void myCallbackMethod (int foo, bool bar);
};
 
ListenerList<MyListenerType> listeners;
listeners.add (someCallbackObjects...);
 
// This will invoke myCallbackMethod (1234, true) on each of the objects
// in the list...
listeners.call ([] (MyListenerType& l) { l.myCallbackMethod (1234, true); });

It is guaranteed that every Listener is called during an iteration if it's inside the ListenerList before the iteration starts and isn't removed until its end. This guarantee holds even if some Listeners are removed or new ones are added during the iteration.

Listeners added during an iteration are guaranteed to be not called in that iteration.

Sometimes, there's a chance that invoking one of the callbacks might result in the list itself being deleted while it's still iterating - to survive this situation, you can use callChecked() instead of call(), passing it a local object to act as a "BailOutChecker". The BailOutChecker must implement a method of the form "bool shouldBailOut()", and the list will check this after each callback to determine whether it should abort the operation. For an example of a bail-out checker, see the Component::BailOutChecker class, which can be used to check when a Component has been deleted. See also ListenerList::DummyBailOutChecker, which is a dummy checker that always returns false.

@tags{Core}