java.awt.event: public class: ComponentEvent

java.awt.event
public class: ComponentEvent [javadoc | source]

java.lang.Object
   java.util.EventObject
      java.awt.AWTEvent
         java.awt.event.ComponentEvent

All Implemented Interfaces:
Serializable

Direct Known Subclasses:
MenuDragMouseEvent, MenuKeyEvent, FocusEvent, MouseEvent, MouseWheelEvent, PaintEvent, InputEvent, KeyEvent, ContainerEvent, WindowEvent

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 ComponentListener or ComponentAdapter object which registered to receive such events using the component's addComponentListener method. (ComponentAdapter objects implement the ComponentListener interface.) Each such listener object gets this ComponentEvent when the event occurs.

An unspecified behavior will be caused if the {@code id} parameter of any particular {@code ComponentEvent} instance is not in the range from {@code COMPONENT_FIRST} to {@code COMPONENT_LAST}.

Also see:

ComponentAdapter

ComponentListener

Tutorial: Writing a Component Listener

author: Carl - Quinn

since: 1.1 -

Field Summary
public static final int	COMPONENT_FIRST	The first number in the range of ids used for component events.
public static final int	COMPONENT_LAST	The last number in the range of ids used for component events.
public static final int	COMPONENT_MOVED	This event indicates that the component's position changed.
public static final int	COMPONENT_RESIZED	This event indicates that the component's size changed.
public static final int	COMPONENT_SHOWN	This event indicates that the component was made visible.
public static final int	COMPONENT_HIDDEN	This event indicates that the component was rendered invisible.

Fields inherited from java.awt.AWTEvent:
id, consumed, focusManagerIsDispatching, isPosted, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, WINDOW_EVENT_MASK, ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, ITEM_EVENT_MASK, TEXT_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INPUT_METHODS_ENABLED_MASK, PAINT_EVENT_MASK, INVOCATION_EVENT_MASK, HIERARCHY_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, WINDOW_STATE_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, RESERVED_ID_MAX

Fields inherited from java.awt.AWTEvent:

id, consumed, focusManagerIsDispatching, isPosted, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, WINDOW_EVENT_MASK, ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, ITEM_EVENT_MASK, TEXT_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INPUT_METHODS_ENABLED_MASK, PAINT_EVENT_MASK, INVOCATION_EVENT_MASK, HIERARCHY_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, WINDOW_STATE_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, RESERVED_ID_MAX

Fields inherited from java.util.EventObject:
source

Constructor:

Constructor:
public ComponentEvent(Component source, int id) { super(source, id); } Constructs a `ComponentEvent` object. This method throws an `IllegalArgumentException` if `source` is `null`. Parameters: `source` - The `Component` that originated the event `id` - An integer indicating the type of event. For information on allowable values, see the class description for ComponentEvent Throws: `IllegalArgumentException` - if `source` is null Also see: getComponent() getID()

 public ComponentEvent(Component source,
    int id) {
                                                                                                          
        super(source, id);
}

ComponentEvent

This method throws an IllegalArgumentException if source is null.

Parameters:

source - The Component that originated the event

id - An integer indicating the type of event. For information on allowable values, see the class description for ComponentEvent

Throws:

IllegalArgumentException - if source is null

Also see:

getComponent()

getID()

Method from java.awt.event.ComponentEvent Summary:
getComponent, paramString

Methods from java.awt.AWTEvent:
consume, convertToOld, copyPrivateDataInto, dispatched, getID, isConsumed, paramString, setSource, toString

Methods from java.util.EventObject:
getSource, toString

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.awt.event.ComponentEvent Detail:
public Component getComponent() { return (source instanceof Component) ? (Component)source : null; } Returns the originator of the event.
public String paramString() { String typeStr; Rectangle b = (source !=null ? ((Component)source).getBounds() : null); switch(id) { case COMPONENT_SHOWN: typeStr = "COMPONENT_SHOWN"; break; case COMPONENT_HIDDEN: typeStr = "COMPONENT_HIDDEN"; break; case COMPONENT_MOVED: typeStr = "COMPONENT_MOVED ("+ b.x+","+b.y+" "+b.width+"x"+b.height+")"; break; case COMPONENT_RESIZED: typeStr = "COMPONENT_RESIZED ("+ b.x+","+b.y+" "+b.width+"x"+b.height+")"; break; default: typeStr = "unknown type"; } return typeStr; } Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

Method from java.awt.event.ComponentEvent Detail:

 public Component getComponent() {
        return (source instanceof Component) ? (Component)source : null;
}

Returns the originator of the event.

 public String paramString() {
        String typeStr;
        Rectangle b = (source !=null
                       ? ((Component)source).getBounds()
                       : null);
        switch(id) {
          case COMPONENT_SHOWN:
              typeStr = "COMPONENT_SHOWN";
              break;
          case COMPONENT_HIDDEN:
              typeStr = "COMPONENT_HIDDEN";
              break;
          case COMPONENT_MOVED:
              typeStr = "COMPONENT_MOVED ("+
                         b.x+","+b.y+" "+b.width+"x"+b.height+")";
              break;
          case COMPONENT_RESIZED:
              typeStr = "COMPONENT_RESIZED ("+
                         b.x+","+b.y+" "+b.width+"x"+b.height+")";
              break;
          default:
              typeStr = "unknown type";
        }
        return typeStr;
}

Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.