| java.lang.Object | |
| ↳ | java.awt.dnd.DragGestureRecognizer |
 Known Direct Subclasses
|
Class Overview
The DragGestureRecognizer is an
abstract base class for the specification
of a platform-dependent listener that can be associated with a particular
Component in order to
identify platform-dependent drag initiating gestures.
The appropriate DragGestureRecognizer
subclass is obtained from the
DragSource associated with
a particular Component, or from the Toolkit
object via its createDragGestureRecognizer() method.
Once the DragGestureRecognizer
is associated with a particular Component
it will register the appropriate listener interfaces on that
Component
in order to track the input events delivered to the Component.
Once the DragGestureRecognizer identifies a sequence of events
on the Component as a drag initiating gesture, it will notify
its unicast DragGestureListener by
invoking its gestureRecognized() method.
When a concrete DragGestureRecognizer
instance detects a drag initiating
gesture on the Component it is associated with,
it will fire a DragGestureEvent to
the DragGestureListener registered on
its unicast event source for DragGestureListener
events. This DragGestureListener is responsible
for causing the associated
DragSource to start the Drag and Drop operation (if
appropriate).
Summary
| Fields | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| component | The Component
associated with this DragGestureRecognizer. |
||||||||||
| dragGestureListener | The DragGestureListener
associated with this DragGestureRecognizer. |
||||||||||
| dragSource | The DragSource
associated with this
DragGestureRecognizer. |
||||||||||
| events | The list of events (in order) that
the DragGestureRecognizer
"recognized" as a "gesture" that triggers a drag. |
||||||||||
| sourceActions | An int representing
the type(s) of action(s) used
in this Drag and Drop operation. |
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| Protected Constructors | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Construct a new
DragGestureRecognizer
given the DragSource to be used
in this Drag and Drop operation, the Component
this DragGestureRecognizer should "observe"
for drag initiating gestures, the action(s) supported
for this Drag and Drop operation, and the
DragGestureListener to notify
once a drag initiating gesture has been detected. | |||||||||||
Construct a new
DragGestureRecognizer
given the DragSource to be used in this
Drag and Drop
operation, the Component this
DragGestureRecognizer should "observe"
for drag initiating gestures, and the action(s)
supported for this Drag and Drop operation. | |||||||||||
Construct a new
DragGestureRecognizer
given the DragSource to be used
in this Drag and Drop operation, and
the Component this
DragGestureRecognizer
should "observe" for drag initiating gestures. | |||||||||||
Construct a new
DragGestureRecognizer
given the DragSource to be used in this
Drag and Drop operation. | |||||||||||
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Register a new
DragGestureListener. | |||||||||||
This method returns the
Component
that is to be "observed" by the
DragGestureRecognizer
for drag initiating gestures. | |||||||||||
This method returns the
DragSource
this DragGestureRecognizer
will use in order to process the Drag and Drop
operation. | |||||||||||
This method returns an int representing the
type of action(s) this Drag and Drop
operation will support.
| |||||||||||
This method returns the first event in the
series of events that initiated
the Drag and Drop operation.
| |||||||||||
unregister the current DragGestureListener
| |||||||||||
Reset the Recognizer, if its currently recognizing a gesture, ignore
it.
| |||||||||||
set the Component that the DragGestureRecognizer is associated with
registerListeners() and unregisterListeners() are called as a side
effect as appropriate.
| |||||||||||
This method sets the permitted source drag action(s)
for this Drag and Drop operation.
| |||||||||||
| Protected Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Listeners registered on the Component by this Recognizer shall record
all Events that are recognized as part of the series of Events that go
to comprise a Drag and Drop initiating gesture via this API.
| |||||||||||
Notify the DragGestureListener that a Drag and Drop initiating
gesture has occurred.
| |||||||||||
register this DragGestureRecognizer's Listeners with the Component
subclasses must override this method
| |||||||||||
unregister this DragGestureRecognizer's Listeners with the Component
subclasses must override this method
| |||||||||||
|
[Expand]
Inherited Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
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From class
java.lang.Object
| |||||||||||
Fields
protected DragGestureListener dragGestureListener
The DragGestureListener
associated with this DragGestureRecognizer.
protected ArrayList<InputEvent> events
The list of events (in order) that
the DragGestureRecognizer
"recognized" as a "gesture" that triggers a drag.
protected int sourceActions
An int representing
the type(s) of action(s) used
in this Drag and Drop operation.
Protected Constructors
protected DragGestureRecognizer (DragSource ds, Component c, int sa, DragGestureListener dgl)
Construct a new DragGestureRecognizer
given the DragSource to be used
in this Drag and Drop operation, the Component
this DragGestureRecognizer should "observe"
for drag initiating gestures, the action(s) supported
for this Drag and Drop operation, and the
DragGestureListener to notify
once a drag initiating gesture has been detected.
Parameters
| ds | the DragSource this
DragGestureRecognizer
will use to process the Drag and Drop operation |
|---|---|
| c | the Component
this DragGestureRecognizer
should "observe" the event stream to,
in order to detect a drag initiating gesture.
If this value is null, the
DragGestureRecognizer
is not associated with any Component. |
| sa | the set (logical OR) of the
DnDConstants
that this Drag and Drop operation will support |
| dgl | the DragGestureRecognizer
to notify when a drag gesture is detected
|
Throws
if ds is null.
|
protected DragGestureRecognizer (DragSource ds, Component c, int sa)
Construct a new DragGestureRecognizer
given the DragSource to be used in this
Drag and Drop
operation, the Component this
DragGestureRecognizer should "observe"
for drag initiating gestures, and the action(s)
supported for this Drag and Drop operation.
Parameters
| ds | the DragSource this
DragGestureRecognizer will use to
process the Drag and Drop operation |
|---|---|
| c | the Component this
DragGestureRecognizer should "observe" the event
stream to, in order to detect a drag initiating gesture.
If this value is null, the
DragGestureRecognizer
is not associated with any Component. |
| sa | the set (logical OR) of the DnDConstants
that this Drag and Drop operation will support
|
Throws
if ds is null.
|
protected DragGestureRecognizer (DragSource ds, Component c)
Construct a new DragGestureRecognizer
given the DragSource to be used
in this Drag and Drop operation, and
the Component this
DragGestureRecognizer
should "observe" for drag initiating gestures.
Parameters
| ds | the DragSource this
DragGestureRecognizer
will use to process the Drag and Drop operation |
|---|---|
| c | the Component
this DragGestureRecognizer
should "observe" the event stream to,
in order to detect a drag initiating gesture.
If this value is null,
the DragGestureRecognizer
is not associated with any Component.
|
Throws
if ds is null.
|
protected DragGestureRecognizer (DragSource ds)
Construct a new DragGestureRecognizer
given the DragSource to be used in this
Drag and Drop operation.
Parameters
| ds | the DragSource this
DragGestureRecognizer will
use to process the Drag and Drop operation
|
|---|
Throws
if ds is null.
|
Public Methods
public synchronized void addDragGestureListener (DragGestureListener dgl)
Register a new DragGestureListener.
Parameters
| dgl | the DragGestureListener to register
with this DragGestureRecognizer.
|
|---|
Throws
| TooManyListenersException | if a
DragGestureListener has already been added.
|
|---|
public synchronized Component getComponent ()
This method returns the Component
that is to be "observed" by the
DragGestureRecognizer
for drag initiating gestures.
Returns
- The Component this DragGestureRecognizer is associated with
public DragSource getDragSource ()
This method returns the DragSource
this DragGestureRecognizer
will use in order to process the Drag and Drop
operation.
Returns
- the DragSource
public synchronized int getSourceActions ()
This method returns an int representing the type of action(s) this Drag and Drop operation will support.
Returns
- the currently permitted source action(s)
public InputEvent getTriggerEvent ()
This method returns the first event in the series of events that initiated the Drag and Drop operation.
Returns
- the initial event that triggered the drag gesture
public synchronized void removeDragGestureListener (DragGestureListener dgl)
unregister the current DragGestureListener
Parameters
| dgl | the DragGestureListener to unregister
from this DragGestureRecognizer
|
|---|
Throws
if
dgl is not (equal to) the currently registered DragGestureListener.
|
public void resetRecognizer ()
Reset the Recognizer, if its currently recognizing a gesture, ignore it.
public synchronized void setComponent (Component c)
set the Component that the DragGestureRecognizer is associated with registerListeners() and unregisterListeners() are called as a side effect as appropriate.
Parameters
| c | The Component or null
|
|---|
public synchronized void setSourceActions (int actions)
This method sets the permitted source drag action(s) for this Drag and Drop operation.
Parameters
| actions | the permitted source drag action(s) |
|---|
Protected Methods
protected synchronized void appendEvent (InputEvent awtie)
Listeners registered on the Component by this Recognizer shall record all Events that are recognized as part of the series of Events that go to comprise a Drag and Drop initiating gesture via this API.
This method is used by a DragGestureRecognizer
implementation to add an InputEvent
subclass (that it believes is one in a series
of events that comprise a Drag and Drop operation)
to the array of events that this
DragGestureRecognizer maintains internally.
Parameters
| awtie | the InputEvent
to add to this DragGestureRecognizer's
internal array of events. Note that null
is not a valid value, and will be ignored.
|
|---|
protected synchronized void fireDragGestureRecognized (int dragAction, Point p)
Notify the DragGestureListener that a Drag and Drop initiating gesture has occurred. Then reset the state of the Recognizer.
Parameters
| dragAction | The action initially selected by the users gesture |
|---|---|
| p | The point (in Component coords) where the gesture originated |
protected abstract void registerListeners ()
register this DragGestureRecognizer's Listeners with the Component subclasses must override this method
protected abstract void unregisterListeners ()
unregister this DragGestureRecognizer's Listeners with the Component subclasses must override this method