java.lang.Object java.util.EventObject java.awt.AWTEvent java.awt.event.ComponentEvent java.awt.event.FocusEvent
A low-level event which indicates that a Component has gained or lost the input focus. This low-level event is generated by a Component (such as a TextField). The event is passed to every FocusListener or FocusAdapter object which registered to receive such events using the Component's addFocusListener method. ( FocusAdapter objects implement the FocusListener interface.) Each such listener object gets this FocusEvent when the event occurs.
There are two levels of focus events: permanent and temporary. Permanent focus change events occur when focus is directly moved from one Component to another, such as through a call to requestFocus() or as the user uses the TAB key to traverse Components. Temporary focus change events occur when focus is temporarily lost for a Component as the indirect result of another operation, such as Window deactivation or a Scrollbar drag. In this case, the original focus state will automatically be restored once that operation is finished, or, for the case of Window deactivation, when the Window is reactivated. Both permanent and temporary focus events are delivered using the FOCUS_GAINED and FOCUS_LOST event ids; the level may be distinguished in the event using the isTemporary() method.
Field Summary | |
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static int |
FOCUS_FIRST
The first number in the range of ids used for focus events. |
static int |
FOCUS_GAINED
This event indicates that the Component is now the focus owner. |
static int |
FOCUS_LAST
The last number in the range of ids used for focus events. |
static int |
FOCUS_LOST
This event indicates that the Component is no longer the focus owner. |
Fields inherited from class java.awt.event. ComponentEvent |
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COMPONENT_FIRST , COMPONENT_HIDDEN , COMPONENT_LAST , COMPONENT_MOVED , COMPONENT_RESIZED , COMPONENT_SHOWN |
Fields inherited from class java.awt. AWTEvent |
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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 |
Fields inherited from class java.util. EventObject |
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source |
Constructor Summary | |
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FocusEvent
(
Component
source, int id) Constructs a FocusEvent object and identifies it as a permanent change in focus. |
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FocusEvent
(
Component
source, int id, boolean temporary) Constructs a FocusEvent object and identifies whether or not the change is temporary. |
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FocusEvent
(
Component
source, int id, boolean temporary,
Component
opposite) Constructs a FocusEvent object with the specified temporary state and opposite Component. |
Method Summary | |
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Component |
getOppositeComponent
() Returns the other Component involved in this focus change. |
boolean |
isTemporary
() Identifies the focus change event as temporary or permanent. |
String |
paramString
() Returns a parameter string identifying this event. |
Methods inherited from class java.awt.event. ComponentEvent |
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getComponent |
Methods inherited from class java.awt. AWTEvent |
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consume , getID , isConsumed , setSource , toString |
Methods inherited from class java.util. EventObject |
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getSource |
Methods inherited from class java.lang. Object |
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait |
Field Detail |
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public static final int FOCUS_FIRST
public static final int FOCUS_LAST
public static final int FOCUS_GAINED
public static final int FOCUS_LOST
Constructor Detail |
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public FocusEvent(Component source, int id, boolean temporary, Component opposite)
Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.
public FocusEvent(Component source, int id, boolean temporary)
Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.
public FocusEvent(Component source, int id)
Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.
Method Detail |
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public boolean isTemporary()
public Component getOppositeComponent()
public String paramString()