juce::ListenerList< ListenerClass, ArrayType > Class Template Reference

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

#include <juce_ListenerList.h>

Inheritance diagram for juce::ListenerList< ListenerClass, ArrayType >:

Collaboration diagram for juce::ListenerList< ListenerClass, ArrayType >:

Classes
struct	DummyBailOutChecker
	A dummy bail-out checker that always returns false. More...
struct	Iterator
	Iterates the listeners in a ListenerList. More...

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

Public Member Functions
	ListenerList ()=default
	Creates an empty list. More...
	~ListenerList ()=default
	Destructor. More...
void	add (ListenerClass *listenerToAdd)
	Adds a listener to the list. More...
template<typename Callback >
void	call (Callback &&callback)
	Calls a member function on each listener in the list, with multiple parameters. More...
template<typename Callback , typename BailOutCheckerType >
void	callChecked (const BailOutCheckerType &bailOutChecker, Callback &&callback)
	Calls a member function on each listener in the list, with 1 parameter and a bail-out-checker. More...
template<typename Callback , typename BailOutCheckerType >
void	callCheckedExcluding (ListenerClass *listenerToExclude, const BailOutCheckerType &bailOutChecker, Callback &&callback)
	Calls a member function, with 1 parameter, on all but the specified listener in the list with a bail-out-checker. More...
template<typename Callback >
void	callExcluding (ListenerClass *listenerToExclude, Callback &&callback)
	Calls a member function with 1 parameter, on all but the specified listener in the list. More...
void	clear ()
	Clears the list. More...
bool	contains (ListenerClass *listener) const noexcept
	Returns true if the specified listener has been added to the list. More...
const ArrayType &	getListeners () const noexcept
	Returns the raw array of listeners. More...
bool	isEmpty () const noexcept
	Returns true if no listeners are registered, false otherwise. More...
void	remove (ListenerClass *listenerToRemove)
	Removes a listener from the list. More...
int	size () const noexcept
	Returns the number of registered listeners. More...

Private Attributes
ArrayType	listeners

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); });

If you add or remove listeners from the list during one of the callbacks - i.e. while it's in the middle of iterating the listeners, then it's guaranteed that no listeners will be mistakenly called after they've been removed, but it may mean that some of the listeners could be called more than once, or not at all, depending on the list's order.

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}

Member Typedef Documentation

ListenerType

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

using juce::ListenerList< ListenerClass, ArrayType >::ListenerType = ListenerClass

ThisType

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

using juce::ListenerList< ListenerClass, ArrayType >::ThisType = ListenerList<ListenerClass, ArrayType>

Constructor & Destructor Documentation

ListenerList()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

juce::ListenerList< ListenerClass, ArrayType >::ListenerList ( )

default

Creates an empty list.

~ListenerList()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

juce::ListenerList< ListenerClass, ArrayType >::~ListenerList ( )

default

Destructor.

Member Function Documentation

add()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::add ( ListenerClass *  listenerToAdd )

inline

Adds a listener to the list.

A listener can only be added once, so if the listener is already in the list, this method has no effect.

See also

remove

call()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

template<typename Callback >

void juce::ListenerList< ListenerClass, ArrayType >::call ( Callback &&  callback )

inline

Calls a member function on each listener in the list, with multiple parameters.

callChecked()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

template<typename Callback , typename BailOutCheckerType >

void juce::ListenerList< ListenerClass, ArrayType >::callChecked ( const BailOutCheckerType &  bailOutChecker, Callback &&  callback  )

inline

Calls a member function on each listener in the list, with 1 parameter and a bail-out-checker.

See the class description for info about writing a bail-out checker.

callCheckedExcluding()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

template<typename Callback , typename BailOutCheckerType >

void juce::ListenerList< ListenerClass, ArrayType >::callCheckedExcluding ( ListenerClass *  listenerToExclude, const BailOutCheckerType &  bailOutChecker, Callback &&  callback  )

inline

Calls a member function, with 1 parameter, on all but the specified listener in the list with a bail-out-checker.

This can be useful if the caller is also a listener and needs to exclude itself. See the class description for info about writing a bail-out checker.

callExcluding()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

template<typename Callback >

void juce::ListenerList< ListenerClass, ArrayType >::callExcluding ( ListenerClass *  listenerToExclude, Callback &&  callback  )

inline

Calls a member function with 1 parameter, on all but the specified listener in the list.

This can be useful if the caller is also a listener and needs to exclude itself.

clear()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::clear ( )

inline

Clears the list.

contains()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

bool juce::ListenerList< ListenerClass, ArrayType >::contains ( ListenerClass *  listener ) const

inlinenoexcept

Returns true if the specified listener has been added to the list.

getListeners()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

const ArrayType& juce::ListenerList< ListenerClass, ArrayType >::getListeners ( ) const

inlinenoexcept

Returns the raw array of listeners.

isEmpty()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

bool juce::ListenerList< ListenerClass, ArrayType >::isEmpty ( ) const

inlinenoexcept

Returns true if no listeners are registered, false otherwise.

remove()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::remove ( ListenerClass *  listenerToRemove )

inline

Removes a listener from the list.

If the listener wasn't in the list, this has no effect.

size()

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

int juce::ListenerList< ListenerClass, ArrayType >::size ( ) const

inlinenoexcept

Returns the number of registered listeners.

Member Data Documentation

listeners

template<class ListenerClass , class ArrayType = Array<ListenerClass*>>

ArrayType juce::ListenerList< ListenerClass, ArrayType >::listeners

private

Referenced by juce::ListenerList< juce::TextEditor::Listener >::add(), juce::ListenerList< juce::TextEditor::Listener >::call(), juce::ListenerList< juce::TextEditor::Listener >::callChecked(), juce::ListenerList< juce::TextEditor::Listener >::callCheckedExcluding(), juce::ListenerList< juce::TextEditor::Listener >::callExcluding(), juce::ListenerList< juce::TextEditor::Listener >::clear(), juce::ListenerList< juce::TextEditor::Listener >::contains(), juce::ListenerList< juce::TextEditor::Listener >::getListeners(), juce::ListenerList< juce::TextEditor::Listener >::isEmpty(), juce::ListenerList< juce::TextEditor::Listener >::remove(), and juce::ListenerList< juce::TextEditor::Listener >::size().

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

• juce_ListenerList.h