Class ComponentEvent
- 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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- All Implemented Interfaces:
- Serializable
- Direct Known Subclasses:
- ContainerEvent, FocusEvent, InputEvent, PaintEvent, WindowEvent
public class ComponentEvent extends AWTEvent
A low-level event which indicates that a component moved, changed size, or changed visibility (also, the root class for the other component-level events).Component events are provided for notification purposes ONLY; The AWT will automatically handle component moves and resizes internally so that GUI layout works properly regardless of whether a program is receiving these events or not.
In addition to serving as the base class for other component-related events (InputEvent, FocusEvent, WindowEvent, ContainerEvent), this class defines the events that indicate changes in a component's size, position, or visibility.
This low-level event is generated by a component object (such as a List) when the component is moved, resized, rendered invisible, or made visible again. The event is passed to every
ComponentListenerorComponentAdapterobject which registered to receive such events using the component'saddComponentListenermethod. (ComponentAdapterobjects implement theComponentListenerinterface.) Each such listener object gets thisComponentEventwhen the event occurs.An unspecified behavior will be caused if the
idparameter of any particularComponentEventinstance is not in the range fromCOMPONENT_FIRSTtoCOMPONENT_LAST.- Since:
- 1.1
- See Also:
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ComponentAdapter,ComponentListener, Tutorial: Writing a Component Listener, Serialized Form
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Field Summary
Fields Modifier and Type Field and Description static intCOMPONENT_FIRSTThe first number in the range of ids used for component events.static intCOMPONENT_HIDDENThis event indicates that the component was rendered invisible.static intCOMPONENT_LASTThe last number in the range of ids used for component events.static intCOMPONENT_MOVEDThis event indicates that the component's position changed.static intCOMPONENT_RESIZEDThis event indicates that the component's size changed.static intCOMPONENT_SHOWNThis event indicates that the component was made visible.-
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 ComponentEvent(Component source, int id)Constructs aComponentEventobject.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description ComponentgetComponent()Returns the originator of the event.StringparamString()Returns a parameter string identifying this event.-
Methods inherited from class java.util.EventObject
getSource
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Field Detail
COMPONENT_FIRST
public static final int COMPONENT_FIRST
The first number in the range of ids used for component events.- See Also:
- Constant Field Values
COMPONENT_LAST
public static final int COMPONENT_LAST
The last number in the range of ids used for component events.- See Also:
- Constant Field Values
COMPONENT_MOVED
@Native public static final int COMPONENT_MOVED
This event indicates that the component's position changed.- See Also:
- Constant Field Values
COMPONENT_RESIZED
@Native public static final int COMPONENT_RESIZED
This event indicates that the component's size changed.- See Also:
- Constant Field Values
COMPONENT_SHOWN
@Native public static final int COMPONENT_SHOWN
This event indicates that the component was made visible.- See Also:
- Constant Field Values
COMPONENT_HIDDEN
@Native public static final int COMPONENT_HIDDEN
This event indicates that the component was rendered invisible.- See Also:
- Constant Field Values
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Constructor Detail
ComponentEvent
public ComponentEvent(Component source, int id)
Constructs aComponentEventobject.This method throws an
IllegalArgumentExceptionifsourceisnull.- Parameters:
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source- TheComponentthat originated the event -
id- An integer indicating the type of event. For information on allowable values, see the class description forComponentEvent - Throws:
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IllegalArgumentException- ifsourceis null - See Also:
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getComponent(),AWTEvent.getID()
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Method Detail
getComponent
public Component getComponent()
Returns the originator of the event.- Returns:
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the
Componentobject that originated the event, ornullif the object is not aComponent.
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 classAWTEvent - 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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