Class ContainerEvent
- java.lang.Object
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- java.util.EventObject
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- java.awt.AWTEvent
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- java.awt.event.ComponentEvent
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- java.awt.event.ContainerEvent
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- All Implemented Interfaces:
- Serializable
public class ContainerEvent extends ComponentEvent
A low-level event which indicates that a container's contents changed because a component was added or removed.Container events are provided for notification purposes ONLY; The AWT will automatically handle changes to the containers contents internally so that the program works properly regardless of whether the program is receiving these events or not.
This low-level event is generated by a container object (such as a Panel) when a component is added to it or removed from it. The event is passed to every
ContainerListenerorContainerAdapterobject which registered to receive such events using the component'saddContainerListenermethod. (ContainerAdapterobjects implement theContainerListenerinterface.) Each such listener object gets thisContainerEventwhen the event occurs.An unspecified behavior will be caused if the
idparameter of any particularContainerEventinstance is not in the range fromCONTAINER_FIRSTtoCONTAINER_LAST.- Since:
- 1.1
- See Also:
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ContainerAdapter,ContainerListener, Tutorial: Writing a Container Listener, Serialized Form
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Field Summary
Fields Modifier and Type Field and Description static intCOMPONENT_ADDEDThis event indicates that a component was added to the container.static intCOMPONENT_REMOVEDThis event indicates that a component was removed from the container.static intCONTAINER_FIRSTThe first number in the range of ids used for container events.static intCONTAINER_LASTThe last number in the range of ids used for container events.-
Fields inherited from class java.awt.event.ComponentEvent
COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN
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Fields inherited from class java.awt.AWTEvent
ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK
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Fields inherited from class java.util.EventObject
source
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Constructor Summary
Constructors Constructor and Description ContainerEvent(Component source, int id, Component child)Constructs aContainerEventobject.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description ComponentgetChild()Returns the component that was affected by the event.ContainergetContainer()Returns the originator of the event.StringparamString()Returns a parameter string identifying this event.-
Methods inherited from class java.awt.event.ComponentEvent
getComponent
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Methods inherited from class java.util.EventObject
getSource
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Field Detail
CONTAINER_FIRST
public static final int CONTAINER_FIRST
The first number in the range of ids used for container events.- See Also:
- Constant Field Values
CONTAINER_LAST
public static final int CONTAINER_LAST
The last number in the range of ids used for container events.- See Also:
- Constant Field Values
COMPONENT_ADDED
public static final int COMPONENT_ADDED
This event indicates that a component was added to the container.- See Also:
- Constant Field Values
COMPONENT_REMOVED
public static final int COMPONENT_REMOVED
This event indicates that a component was removed from the container.- See Also:
- Constant Field Values
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Constructor Detail
ContainerEvent
public ContainerEvent(Component source, int id, Component child)
Constructs aContainerEventobject.This method throws an
IllegalArgumentExceptionifsourceisnull.- Parameters:
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source- TheComponentobject (container) that originated the event -
id- An integer indicating the type of event. For information on allowable values, see the class description forContainerEvent -
child- the component that was added or removed - Throws:
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IllegalArgumentException- ifsourceis null - See Also:
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getContainer(),AWTEvent.getID(),getChild()
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Method Detail
getContainer
public Container getContainer()
Returns the originator of the event.- Returns:
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the
Containerobject that originated the event, ornullif the object is not aContainer.
getChild
public Component getChild()
Returns the component that was affected by the event.- Returns:
- the Component object that was added or removed
paramString
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.- Overrides:
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paramStringin classComponentEvent - Returns:
- a string identifying the event and its attributes
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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