juce::ComponentListener Class Reference

Detailed Description

Gets informed about changes to a component's hierarchy or position.

To monitor a component for changes, register a subclass of ComponentListener with the component using Component::addComponentListener().

Be sure to deregister listeners before you delete them!

See also

Component::addComponentListener, Component::removeComponentListener

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

• juce_gui_basics/components/juce_ComponentListener.h

Inheritance diagram for juce::ComponentListener:

Public Member Functions
virtual	~ComponentListener ()=default
	Destructor.
virtual void	componentMovedOrResized (Component &component, bool wasMoved, bool wasResized)
	Called when the component's position or size changes.
virtual void	componentBroughtToFront (Component &component)
	Called when the component is brought to the top of the z-order.
virtual void	componentVisibilityChanged (Component &component)
	Called when the component is made visible or invisible.
virtual void	componentChildrenChanged (Component &component)
	Called when the component has children added or removed, or their z-order changes.
virtual void	componentParentHierarchyChanged (Component &component)
	Called to indicate that the component's parents have changed.
virtual void	componentNameChanged (Component &component)
	Called when the component's name is changed.
virtual void	componentBeingDeleted (Component &component)
	Called when the component is in the process of being deleted.
virtual void	componentEnablementChanged (Component &component)
virtual void	componentPainted (Component &component, const ComponentPaintDiagnostics &diagnostics)
	Called each time the component is painted into a context.

Constructors and Destructors

~ComponentListener()

virtual juce::ComponentListener::~ComponentListener ( )

virtualdefault

Destructor.

Member Functions

componentMovedOrResized()

virtual void juce::ComponentListener::componentMovedOrResized ( Component & component, bool wasMoved, bool wasResized )

virtual

Called when the component's position or size changes.

Parameters

component	the component that was moved or resized
wasMoved	true if the component's top-left corner has just moved
wasResized	true if the component's width or height has just changed

See also

Component::setBounds, Component::resized, Component::moved

Reimplemented in juce::ComponentMovementWatcher, juce::Label, juce::RelativeCoordinatePositionerBase, and juce::Viewport.

componentBroughtToFront()

virtual void juce::ComponentListener::componentBroughtToFront ( Component & component )

virtual

Called when the component is brought to the top of the z-order.

Parameters

component

the component that was moved

See also

Component::toFront, Component::broughtToFront

componentVisibilityChanged()

virtual void juce::ComponentListener::componentVisibilityChanged ( Component & component )

virtual

Called when the component is made visible or invisible.

Parameters

component

the component that changed

See also

Component::setVisible

Reimplemented in juce::ComponentMovementWatcher, and juce::Label.

componentChildrenChanged()

virtual void juce::ComponentListener::componentChildrenChanged ( Component & component )

virtual

Called when the component has children added or removed, or their z-order changes.

Parameters

component

the component whose children have changed

See also

Component::childrenChanged, Component::addChildComponent, Component::removeChildComponent

Reimplemented in juce::RelativeCoordinatePositionerBase.

componentParentHierarchyChanged()

virtual void juce::ComponentListener::componentParentHierarchyChanged ( Component & component )

virtual

Called to indicate that the component's parents have changed.

When a component is added or removed from its parent, all of its children will produce this notification (recursively - so all children of its children will also be called as well).

Parameters

component

the component that this listener is registered with

See also

Component::parentHierarchyChanged

Reimplemented in juce::ComponentMovementWatcher, juce::Label, and juce::RelativeCoordinatePositionerBase.

componentNameChanged()

virtual void juce::ComponentListener::componentNameChanged ( Component & component )

virtual

Called when the component's name is changed.

Parameters

component

the component that had its name changed

See also

Component::setName, Component::getName

Reimplemented in juce::MultiDocumentPanel.

componentBeingDeleted()

virtual void juce::ComponentListener::componentBeingDeleted ( Component & component )

virtual

Called when the component is in the process of being deleted.

This callback is made from inside the destructor, so be very, very cautious about what you do in here.

In particular, bear in mind that it's the Component base class's destructor that calls this - so if the object that's being deleted is a subclass of Component, then the subclass layers of the object will already have been destructed when it gets to this point!

Parameters

component

the component that was deleted

Reimplemented in juce::ComponentMovementWatcher, and juce::RelativeCoordinatePositionerBase.

componentEnablementChanged()

virtual void juce::ComponentListener::componentEnablementChanged ( Component & component )

virtual

componentPainted()

virtual void juce::ComponentListener::componentPainted ( Component & component, const ComponentPaintDiagnostics & diagnostics )

virtual

Called each time the component is painted into a context.

This will be called once, each time the component is painted into a graphics context. This might be to paint the component directly or to paint a cached image of the component. To get more detailed information regarding user overridable paint methods see componentPaintMethodsCalled().

This callback may be called while trying to paint components. This means the time taken in this callback may be taken into account as part of any parent components ComponentPaintDiagnostics. Therefore, an effort should be made to keep any work in this callback to a bare minimum in order to prevent distorting any results.

It's important not to rely on the precise timing of this callback. The only guarantees are that the callback will occur some time after the component is painted (although the contents of that paint call may not have been updated to the screen).

Parameters

component	the component that was painted
diagnostics	general diagnostics for painting the component

See also

componentPaintMethodsCalled