ActionListener
, EventListener
AbstractAction
, BasicDesktopPaneUI.CloseAction
, BasicDesktopPaneUI.MaximizeAction
, BasicDesktopPaneUI.MinimizeAction
, BasicDesktopPaneUI.NavigateAction
, BasicDesktopPaneUI.OpenAction
, BasicFileChooserUI.ApproveSelectionAction
, BasicFileChooserUI.CancelSelectionAction
, BasicFileChooserUI.ChangeToParentDirectoryAction
, BasicFileChooserUI.GoHomeAction
, BasicFileChooserUI.NewFolderAction
, BasicFileChooserUI.UpdateAction
, BasicInternalFrameTitlePane.CloseAction
, BasicInternalFrameTitlePane.IconifyAction
, BasicInternalFrameTitlePane.MaximizeAction
, BasicInternalFrameTitlePane.MoveAction
, BasicInternalFrameTitlePane.RestoreAction
, BasicInternalFrameTitlePane.SizeAction
, BasicSliderUI.ActionScroller
, BasicTreeUI.TreeCancelEditingAction
, BasicTreeUI.TreeHomeAction
, BasicTreeUI.TreeIncrementAction
, BasicTreeUI.TreePageAction
, BasicTreeUI.TreeToggleAction
, BasicTreeUI.TreeTraverseAction
, DefaultEditorKit.BeepAction
, DefaultEditorKit.CopyAction
, DefaultEditorKit.CutAction
, DefaultEditorKit.DefaultKeyTypedAction
, DefaultEditorKit.InsertBreakAction
, DefaultEditorKit.InsertContentAction
, DefaultEditorKit.InsertTabAction
, DefaultEditorKit.PasteAction
, HTMLEditorKit.HTMLTextAction
, HTMLEditorKit.InsertHTMLTextAction
, MetalFileChooserUI.DirectoryComboBoxAction
, StyledEditorKit.AlignmentAction
, StyledEditorKit.BoldAction
, StyledEditorKit.FontFamilyAction
, StyledEditorKit.FontSizeAction
, StyledEditorKit.ForegroundAction
, StyledEditorKit.ItalicAction
, StyledEditorKit.StyledTextAction
, StyledEditorKit.UnderlineAction
, TextAction
public interface Action extends ActionListener
Action
interface provides a useful extension to the
ActionListener
interface in cases where the same functionality may be accessed by
several controls.
In addition to the actionPerformed
method defined by the
ActionListener
interface, this interface allows the
application to define, in a single place:
This interface can be added to an existing class or used to create an
adapter (typically, by subclassing AbstractAction
).
The Action
object
can then be added to multiple Action
-aware containers
and connected to Action
-capable
components. The GUI controls can then be activated or
deactivated all at once by invoking the Action
object's
setEnabled
method.
Note that Action
implementations tend to be more expensive
in terms of storage than a typical ActionListener
,
which does not offer the benefits of centralized control of
functionality and broadcast of property changes. For this reason,
you should take care to only use Action
s where their benefits
are desired, and use simple ActionListener
s elsewhere.
Action
Many of Swing's components have an Action
property. When
an Action
is set on a component, the following things
happen:
Action
is added as an ActionListener
to
the component.
Action
.
PropertyChangeListener
on the
Action
so that the component can change its properties
to reflect changes in the Action
's properties.
The following table describes the properties used by
Swing
components that support Actions
.
In the table, button refers to any
AbstractButton
subclass, which includes not only
JButton
but also classes such as
JMenuItem
. Unless otherwise stated, a
null
property value in an Action
(or a
Action
that is null
) results in the
button's corresponding property being set to null
.
Component Property | Components | Action Key | Notes |
---|---|---|---|
enabled
| All | The isEnabled method
| |
toolTipText
| All | SHORT_DESCRIPTION
| |
actionCommand
| All | ACTION_COMMAND_KEY
| |
mnemonic
| All buttons | MNEMONIC_KEY
| A null value or Action results in the
button's mnemonic property being set to
'\0' .
|
text
| All buttons | NAME
| If you do not want the text of the button to mirror that
of the Action , set the property
hideActionText to true . If
hideActionText is true , setting the
Action changes the text of the button to
null and any changes to NAME
are ignored. hideActionText is useful for
tool bar buttons that typically only show an Icon .
JToolBar.add(Action) sets the property to
true if the Action has a
non-null value for LARGE_ICON_KEY or
SMALL_ICON .
|
displayedMnemonicIndex
| All buttons | DISPLAYED_MNEMONIC_INDEX_KEY
| If the value of DISPLAYED_MNEMONIC_INDEX_KEY is
beyond the bounds of the text, it is ignored. When
setAction is called, if the value from the
Action is null , the displayed
mnemonic index is not updated. In any subsequent changes to
DISPLAYED_MNEMONIC_INDEX_KEY , null
is treated as -1.
|
icon
| All buttons except of JCheckBox ,
JToggleButton and JRadioButton .
| either LARGE_ICON_KEY or
SMALL_ICON
| The JMenuItem subclasses only use
SMALL_ICON . All other buttons will use
LARGE_ICON_KEY ; if the value is null they
use SMALL_ICON .
|
accelerator
| All JMenuItem subclasses, with the exception of
JMenu .
| ACCELERATOR_KEY
| |
selected
| JToggleButton , JCheckBox ,
JRadioButton , JCheckBoxMenuItem and
JRadioButtonMenuItem
| SELECTED_KEY
| Components that honor this property only use
the value if it is non-null . For example, if
you set an Action that has a null
value for SELECTED_KEY on a JToggleButton , the
JToggleButton will not update it's selected state in
any way. Similarly, any time the JToggleButton 's
selected state changes it will only set the value back on
the Action if the Action has a non-null
value for SELECTED_KEY .
Components that honor this property keep their selected state in sync with this property. When the same Action is used
with multiple components, all the components keep their selected
state in sync with this property. Mutually exclusive
buttons, such as JToggleButton s in a ButtonGroup ,
force only one of the buttons to be selected. As such, do not
use the same Action that defines a value for the
SELECTED_KEY property with multiple mutually
exclusive buttons.
|
JPopupMenu
, JToolBar
and JMenu
all provide convenience methods for creating a component and setting the
Action
on the corresponding component. Refer to each of
these classes for more information.
Action
uses PropertyChangeListener
to
inform listeners the Action
has changed. The beans
specification indicates that a null
property name can
be used to indicate multiple values have changed. By default Swing
components that take an Action
do not handle such a
change. To indicate that Swing should treat null
according to the beans specification set the system property
swing.actions.reconfigureOnNull
to the String
value true
.
AbstractAction
Modifier and Type | Field | Description |
---|---|---|
static String |
ACCELERATOR_KEY |
The key used for storing a
KeyStroke to be used as the
accelerator for the action. |
static String |
ACTION_COMMAND_KEY |
The key used to determine the command
String for the
ActionEvent that will be created when an
Action is going to be notified as the result of
residing in a Keymap associated with a
JComponent . |
static String |
DEFAULT |
Not currently used.
|
static String |
DISPLAYED_MNEMONIC_INDEX_KEY |
The key used for storing an
Integer that corresponds
to the index in the text (identified by the NAME
property) that the decoration for a mnemonic should be rendered at. |
static String |
LARGE_ICON_KEY |
The key used for storing an
Icon . |
static String |
LONG_DESCRIPTION |
The key used for storing a longer
String
description for the action, could be used for context-sensitive help. |
static String |
MNEMONIC_KEY |
The key used for storing an
Integer that corresponds to
one of the KeyEvent key codes. |
static String |
NAME |
The key used for storing the
String name
for the action, used for a menu or button. |
static String |
SELECTED_KEY |
The key used for storing a
Boolean that corresponds
to the selected state. |
static String |
SHORT_DESCRIPTION |
The key used for storing a short
String
description for the action, used for tooltip text. |
static String |
SMALL_ICON |
The key used for storing a small
Icon , such
as ImageIcon . |
Modifier and Type | Method | Description |
---|---|---|
default boolean |
accept(Object sender) |
Determines whether the action should be performed with the specified
sender object.
|
void |
addPropertyChangeListener(PropertyChangeListener listener) |
Adds a
PropertyChange listener. |
Object |
getValue(String key) |
Gets one of this object's properties
using the associated key.
|
boolean |
isEnabled() |
Returns the enabled state of the
Action . |
void |
putValue(String key,
Object value) |
Sets one of this object's properties
using the associated key.
|
void |
removePropertyChangeListener(PropertyChangeListener listener) |
Removes a
PropertyChange listener. |
void |
setEnabled(boolean b) |
Sets the enabled state of the
Action . |
actionPerformed
static final String DEFAULT
static final String NAME
String
name
for the action, used for a menu or button.static final String SHORT_DESCRIPTION
String
description for the action, used for tooltip text.static final String LONG_DESCRIPTION
String
description for the action, could be used for context-sensitive help.static final String SMALL_ICON
Icon
, such
as ImageIcon
. This is typically used with
menus such as JMenuItem
.
If the same Action
is used with menus and buttons you'll
typically specify both a SMALL_ICON
and a
LARGE_ICON_KEY
. The menu will use the
SMALL_ICON
and the button will use the
LARGE_ICON_KEY
.
static final String ACTION_COMMAND_KEY
String
for the
ActionEvent
that will be created when an
Action
is going to be notified as the result of
residing in a Keymap
associated with a
JComponent
.static final String ACCELERATOR_KEY
KeyStroke
to be used as the
accelerator for the action.static final String MNEMONIC_KEY
Integer
that corresponds to
one of the KeyEvent
key codes. The value is
commonly used to specify a mnemonic. For example:
myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A)
sets the mnemonic of myAction
to 'a', while
myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('?'))
sets the mnemonic of myAction
to Cyrillic letter "Ef".static final String SELECTED_KEY
Boolean
that corresponds
to the selected state. This is typically used only for components
that have a meaningful selection state. For example,
JRadioButton
and JCheckBox
make use of
this but instances of JMenu
don't.
This property differs from the others in that it is both read
by the component and set by the component. For example,
if an Action
is attached to a JCheckBox
the selected state of the JCheckBox
will be set from
that of the Action
. If the user clicks on the
JCheckBox
the selected state of the JCheckBox
and the Action
will both be updated.
Note: the value of this field is prefixed with 'Swing' to
avoid possible collisions with existing Actions
.
static final String DISPLAYED_MNEMONIC_INDEX_KEY
Integer
that corresponds
to the index in the text (identified by the NAME
property) that the decoration for a mnemonic should be rendered at. If
the value of this property is greater than or equal to the length of
the text, it will treated as -1.
Note: the value of this field is prefixed with 'Swing' to
avoid possible collisions with existing Actions
.
AbstractButton.setDisplayedMnemonicIndex(int)
,
Constant Field Valuesstatic final String LARGE_ICON_KEY
Icon
. This is typically
used by buttons, such as JButton
and
JToggleButton
.
If the same Action
is used with menus and buttons you'll
typically specify both a SMALL_ICON
and a
LARGE_ICON_KEY
. The menu will use the
SMALL_ICON
and the button the LARGE_ICON_KEY
.
Note: the value of this field is prefixed with 'Swing' to
avoid possible collisions with existing Actions
.
Object getValue(String key)
key
- a String
containing the keyObject
valueputValue(java.lang.String, java.lang.Object)
void putValue(String key, Object value)
PropertyChangeEvent
is sent
to listeners.key
- a String
containing the keyvalue
- an Object
valuevoid setEnabled(boolean b)
Action
. When enabled,
any component associated with this object is active and
able to fire this object's actionPerformed
method.
If the value has changed, a PropertyChangeEvent
is sent
to listeners.b
- true to enable this Action
, false to disable itaccept(java.lang.Object)
boolean isEnabled()
Action
. When enabled,
any component associated with this object is active and
able to fire this object's actionPerformed
method.Action
is enabledaccept(java.lang.Object)
default boolean accept(Object sender)
sender
can be null
.
The method must return false if the action is disabled.
sender
- the object to check, can be nulltrue
if the action should be performed with the sender
object, must be false if the action is disabled.isEnabled()
,
setEnabled(boolean)
void addPropertyChangeListener(PropertyChangeListener listener)
PropertyChange
listener. Containers and attached
components use these methods to register interest in this
Action
object. When its enabled state or other property
changes, the registered listeners are informed of the change.listener
- a PropertyChangeListener
objectvoid removePropertyChangeListener(PropertyChangeListener listener)
PropertyChange
listener.listener
- a PropertyChangeListener
objectaddPropertyChangeListener(java.beans.PropertyChangeListener)
Submit a bug or feature
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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DRAFT 9-internal+0-adhoc.mlchung.jdk9-jdeps