Serializablepublic class FocusEvent extends ComponentEvent
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.
Every FocusEvent records its cause - the reason why this event was generated. The cause is assigned during the focus event creation and may be retrieved by calling getCause().
An unspecified behavior will be caused if the id parameter of any particular FocusEvent instance is not in the range from FOCUS_FIRST to FOCUS_LAST.
| Modifier and Type | Class | Description |
|---|---|---|
static enum |
FocusEvent.Cause |
This enum represents the cause of a FocusEvent- the reason why it occurred. |
| Modifier and Type | Field | Description |
|---|---|---|
static final int |
FOCUS_FIRST |
The first number in the range of ids used for focus events. |
static final int |
FOCUS_GAINED |
This event indicates that the Component is now the focus owner. |
static final int |
FOCUS_LAST |
The last number in the range of ids used for focus events. |
static final int |
FOCUS_LOST |
This event indicates that the Component is no longer the focus owner. |
COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN
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
source
| Constructor | Description |
|---|---|
FocusEvent |
Constructs a FocusEvent object and identifies it as a permanent change in focus. |
FocusEvent |
Constructs a FocusEvent object and identifies whether or not the change is temporary. |
FocusEvent |
Constructs a FocusEvent object with the specified temporary state, opposite Component and the Cause.UNKNOWN cause. |
FocusEvent |
Constructs a FocusEvent object with the specified temporary state, opposite Component and the cause. |
| Modifier and Type | Method | Description |
|---|---|---|
final FocusEvent.Cause |
getCause() |
Returns the event cause. |
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. |
getComponent
getSource
public static final int FOCUS_FIRST
public static final int FOCUS_LAST
public static final int FOCUS_GAINED
public static final int FOCUS_LOST
public FocusEvent(Component source, int id, boolean temporary, Component opposite)
FocusEvent object with the specified temporary state, opposite Component and the Cause.UNKNOWN cause. The opposite Component is the other Component involved in this focus change. For a FOCUS_GAINED event, this is the Component that lost focus. For a FOCUS_LOST event, this is the Component that gained focus. If this focus change occurs with a native application, with a Java application in a different VM, or with no other Component, then the opposite Component is null. This method throws an IllegalArgumentException if source is null.
source - The Component that originated the eventid - An integer indicating the type of event. For information on allowable values, see the class description for FocusEvent
temporary - Equals true if the focus change is temporary; false otherwiseopposite - The other Component involved in the focus change, or null
IllegalArgumentException - if source equals null
public FocusEvent(Component source, int id, boolean temporary, Component opposite, FocusEvent.Cause cause)
FocusEvent object with the specified temporary state, opposite Component and the cause. The opposite Component is the other Component involved in this focus change. For a FOCUS_GAINED event, this is the Component that lost focus. For a FOCUS_LOST event, this is the Component that gained focus. If this focus change occurs with a native application, with a Java application in a different VM, or with no other Component, then the opposite Component is null. This method throws an IllegalArgumentException if source or cause is null.
source - The Component that originated the eventid - An integer indicating the type of event. For information on allowable values, see the class description for FocusEvent
temporary - Equals true if the focus change is temporary; false otherwiseopposite - The other Component involved in the focus change, or null
cause - The focus event cause.IllegalArgumentException - if source equals null or if cause equals null
public FocusEvent(Component source, int id, boolean temporary)
FocusEvent object and identifies whether or not the change is temporary. This method throws an IllegalArgumentException if source is null.
source - The Component that originated the eventid - An integer indicating the type of event. For information on allowable values, see the class description for FocusEvent
temporary - Equals true if the focus change is temporary; false otherwiseIllegalArgumentException - if source equals null
public FocusEvent(Component source, int id)
FocusEvent object and identifies it as a permanent change in focus. This method throws an IllegalArgumentException if source is null.
source - The Component that originated the eventid - An integer indicating the type of event. For information on allowable values, see the class description for FocusEvent
IllegalArgumentException - if source equals null
public boolean isTemporary()
true if the focus change is temporary; false otherwisepublic Component getOppositeComponent()
public String paramString()
paramString in class ComponentEvent
public final FocusEvent.Cause getCause()
FocusEvent.Cause values
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/event/FocusEvent.html