sdk doc change: Copy/Paste/Drag/Drop (32736f08) · Commits · e / os / android_frameworks_base

core/java/android/view/DragEvent.java

+250 −78

Original line number	Diff line number	Diff line
		@@ -21,7 +21,100 @@ import android.content.ClipDescription;
		import android.os.Parcel;
		import android.os.Parcelable;

		/** !!! TODO: real docs */
		//TODO: Improve Javadoc
		/**
		* Represents an event that is sent out by the system at various times during a drag and drop
		* operation. It is a complex data structure that contains several important pieces of data about
		* the operation and the underlying data.
		* <p>
		* View objects that receive a DragEvent call {@link #getAction()}, which returns
		* an action type that indicates the state of the drag and drop operation. This allows a View
		* object to react to a change in state by changing its appearance or performing other actions.
		* For example, a View can react to the {@link #ACTION_DRAG_ENTERED} action type by
		* by changing one or more colors in its displayed image.
		* </p>
		* <p>
		* During a drag and drop operation, the system displays an image that the user drags. This image
		* is called a drag shadow. Several action types reflect the position of the drag shadow relative
		* to the View receiving the event.
		* </p>
		* <p>
		* Most methods return valid data only for certain event actions. This is summarized in the
		* following table. Each possible {@link #getAction()} value is listed in the first column. The
		* other columns indicate which method or methods return valid data for that getAction() value:
		* </p>
		* <table>
		* <tr>
		* <th scope="col">getAction() Value</th>
		* <th scope="col">getClipDescription()</th>
		* <th scope="col">getLocalState()</th>
		* <th scope="col">getX()</th>
		* <th scope="col">getY()</th>
		* <th scope="col">getClipData()</th>
		* <th scope="col">getResult()</th>
		* </tr>
		* <tr>
		* <td>ACTION_DRAG_STARTED</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* </tr>
		* <tr>
		* <td>ACTION_DRAG_ENTERED</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* </tr>
		* <tr>
		* <td>ACTION_DRAG_LOCATION</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* </tr>
		* <tr>
		* <td>ACTION_DRAG_EXITED</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* </tr>
		* <tr>
		* <td>ACTION_DROP</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* </tr>
		* <tr>
		* <td>ACTION_DRAG_ENDED</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;">X</td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;"> </td>
		* <td style="text-align: center;">X</td>
		* </tr>
		* </table>
		* <p>
		* The {@link android.view.DragEvent#getAction()},
		* {@link android.view.DragEvent#describeContents()},
		* {@link android.view.DragEvent#writeToParcel(Parcel,int)}, and
		* {@link android.view.DragEvent#toString()} methods always return valid data.
		* </p>
		*/
		public class DragEvent implements Parcelable {
		private static final boolean TRACK_RECYCLED_LOCATION = false;

		@@ -42,87 +135,111 @@ public class DragEvent implements Parcelable {
		private static DragEvent gRecyclerTop = null;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DRAG_STARTED means that a drag operation has been initiated. The
		* view receiving this DragEvent should inspect the metadata of the dragged content,
		* available via {@link #getClipDescription()}, and return {@code true} from
		* {@link View#onDragEvent(DragEvent)} if the view is prepared to accept a drop of
		* that clip data. If the view chooses to present a visual indication that it is
		* a valid target of the ongoing drag, then it should draw that indication in response
		* to this event.
		* Action constant returned by {@link #getAction()}: Signals the start of a
		* drag and drop operation. The View should return {@code true} from its
		* {@link View#onDragEvent(DragEvent) onDragEvent()} handler method or
		* {@link View.View.OnDragListener#onDrag(View,DragEvent) OnDragListener.onDrag()} listener
		* if it can accept a drop. The onDragEvent() or onDrag() methods usually inspect the metadata
		* from {@link #getClipDescription()} to determine if they can accept the data contained in
		* this drag. For an operation that doesn't represent data transfer, these methods may
		* perform other actions to determine whether or not the View should accept the drag.
		* If the View wants to indicate that it is a valid drop target, it can also react by
		* changing its appearance.
		* <p>
		* A view will only receive ACTION_DRAG_ENTERED, ACTION_DRAG_LOCATION, ACTION_DRAG_EXITED,
		* and ACTION_DRAG_LOCATION events if it returns {@code true} in response to the
		* ACTION_DRAG_STARTED event.
		* A View only receives further drag events if it returns {@code true} in response to
		* ACTION_DRAG_STARTED.
		* </p>
		* @see #ACTION_DRAG_ENDED
		*/
		public static final int ACTION_DRAG_STARTED = 1;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DRAG_LOCATION means that the drag operation is currently hovering
		* over the view. The {@link #getX()} and {@link #getY()} methods supply the location
		* of the drag point within the view's coordinate system.
		* Action constant returned by {@link #getAction()}: Sent to a View after
		* {@link #ACTION_DRAG_ENTERED} if the drag shadow is still within the View object's bounding
		* box. The {@link #getX()} and {@link #getY()} methods supply
		* the X and Y position of of the drag point within the View object's bounding box.
		* <p>
		* A view will receive an ACTION_DRAG_ENTERED event before receiving any
		* ACTION_DRAG_LOCATION events. If the drag point leaves the view, then an
		* ACTION_DRAG_EXITED event is delivered to the view, after which no more
		* ACTION_DRAG_LOCATION events will be sent (unless the drag re-enters the view,
		* of course).
		* A View receives an {@link #ACTION_DRAG_ENTERED} event before receiving any
		* ACTION_DRAG_LOCATION events.
		* </p>
		* <p>
		* The system stops sending ACTION_DRAG_LOCATION events to a View once the user moves the
		* drag shadow out of the View object's bounding box. If the user moves the drag shadow back
		* into the View object's bounding box, the View receives an ACTION_DRAG_ENTERED again before
		* receiving any more ACTION_DRAG_LOCATION events.
		* </p>
		* @see #ACTION_DRAG_ENTERED
		* @see #getX()
		* @see #getY()
		*/
		public static final int ACTION_DRAG_LOCATION = 2;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DROP means that the dragged content has been dropped on this view.
		* The view should retrieve the content via {@link #getClipData()} and act on it
		* appropriately. The {@link #getX()} and {@link #getY()} methods supply the location
		* of the drop point within the view's coordinate system.
		* Action constant returned by {@link #getAction()}: Signals to a View that the user
		* has released the drag shadow, and the drag point is within the bounding box of the View.
		* The View should retrieve the data from the DragEvent by calling {@link #getClipData()}.
		* The methods {@link #getX()} and {@link #getY()} return the X and Y position of the drop point
		* within the View object's bounding box.
		* <p>
		* The View should return {@code true} from its {@link View#onDragEvent(DragEvent)}
		* handler or {@link View.View.OnDragListener#onDrag(View,DragEvent) OnDragListener.onDrag()}
		* listener if it accepted the drop, and {@code false} if it ignored the drop.
		* </p>
		* <p>
		* The view should return {@code true} from its {@link View#onDragEvent(DragEvent)}
		* method in response to this event if it accepted the content, and {@code false}
		* if it ignored the drop.
		* The View can also react to this action by changing its appearance.
		* </p>
		* @see #getClipData()
		* @see #getX()
		* @see #getY()
		*/
		public static final int ACTION_DROP = 3;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DRAG_ENDED means that the drag operation has concluded. A view
		* that is drawing a visual indication of drag acceptance should return to its usual
		* drawing state in response to this event.
		* Action constant returned by {@link #getAction()}: Signals to a View that the drag and drop
		* operation has concluded. A View that changed its appearance during the operation should
		* return to its usual drawing state in response to this event.
		* <p>
		* All views that received an ACTION_DRAG_STARTED event will receive the
		* ACTION_DRAG_ENDED event even if they are not currently visible when the drag
		* ends.
		* ACTION_DRAG_ENDED event even if they are not currently visible when the drag ends.
		* </p>
		* <p>
		* The View object can call {@link #getResult()} to see the result of the operation.
		* If a View returned {@code true} in response to {@link #ACTION_DROP}, then
		* getResult() returns {@code true}, otherwise it returns {@code false}.
		* </p>
		* @see #ACTION_DRAG_STARTED
		* @see #getResult()
		*/
		public static final int ACTION_DRAG_ENDED = 4;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DRAG_ENTERED means that the drag point has entered the view's
		* bounds. If the view changed its visual state in response to the ACTION_DRAG_ENTERED
		* event, it should return to its normal drag-in-progress visual state in response to
		* this event.
		* Action constant returned by {@link #getAction()}: Signals to a View that the drag point has
		* entered the bounding box of the View.
		* <p>
		* A view will receive an ACTION_DRAG_ENTERED event before receiving any
		* ACTION_DRAG_LOCATION events. If the drag point leaves the view, then an
		* ACTION_DRAG_EXITED event is delivered to the view, after which no more
		* ACTION_DRAG_LOCATION events will be sent (unless the drag re-enters the view,
		* of course).
		* If the View can accept a drop, it can react to ACTION_DRAG_ENTERED
		* by changing its appearance in a way that tells the user that the View is the current
		* drop target.
		* </p>
		* The system stops sending ACTION_DRAG_LOCATION events to a View once the user moves the
		* drag shadow out of the View object's bounding box. If the user moves the drag shadow back
		* into the View object's bounding box, the View receives an ACTION_DRAG_ENTERED again before
		* receiving any more ACTION_DRAG_LOCATION events.
		* </p>
		* @see #ACTION_DRAG_ENTERED
		* @see #ACTION_DRAG_LOCATION
		*/
		public static final int ACTION_DRAG_ENTERED = 5;

		/**
		* Action constant returned by {@link #getAction()}. Delivery of a DragEvent whose
		* action is ACTION_DRAG_ENTERED means that the drag point has entered the view's
		* bounds. If the view chooses to present a visual indication that it will receive
		* the drop if it occurs now, then it should draw that indication in response to
		* this event.
		* Action constant returned by {@link #getAction()}: Signals that the user has moved the
		* drag shadow outside the bounding box of the View.
		* The View can react by changing its appearance in a way that tells the user that
		* View is no longer the immediate drop target.
		* <p>
		* A view will receive an ACTION_DRAG_ENTERED event before receiving any
		* ACTION_DRAG_LOCATION events. If the drag point leaves the view, then an
		* ACTION_DRAG_EXITED event is delivered to the view, after which no more
		* ACTION_DRAG_LOCATION events will be sent (unless the drag re-enters the view,
		* of course).
		* After the system sends an ACTION_DRAG_EXITED event to the View, the View receives no more
		* ACTION_DRAG_LOCATION events until the user drags the drag shadow back over the View.
		* </p>
		*
		*/
		public static final int ACTION_DRAG_EXITED = 6;

		@@ -175,64 +292,101 @@ public static final int ACTION_DRAG_EXITED = 6;

		/**
		* Inspect the action value of this event.
		* @return One of {@link #ACTION_DRAG_STARTED}, {@link #ACTION_DRAG_ENDED},
		* {@link #ACTION_DROP}, {@link #ACTION_DRAG_ENTERED}, {@link #ACTION_DRAG_EXITED},
		* or {@link #ACTION_DRAG_LOCATION}.
		* @return One of the following action constants, in the order in which they usually occur
		* during a drag and drop operation:
		* <ul>
		* <li>{@link #ACTION_DRAG_STARTED}</li>
		* <li>{@link #ACTION_DRAG_ENTERED}</li>
		* <li>{@link #ACTION_DRAG_LOCATION}</li>
		* <li>{@link #ACTION_DROP}</li>
		* <li>{@link #ACTION_DRAG_EXITED}</li>
		* <li>{@link #ACTION_DRAG_ENDED}</li>
		* </ul>
		*/
		public int getAction() {
		return mAction;
		}

		/**
		* For ACTION_DRAG_LOCATION and ACTION_DROP events, returns the x coordinate of the
		* drag point.
		* @return The current drag point's x coordinate, when relevant.
		* Gets the X coordinate of the drag point. The value is only valid if the event action is
		* {@link #ACTION_DRAG_LOCATION} or {@link #ACTION_DROP}.
		* @return The current drag point's Y coordinate
		*/
		public float getX() {
		return mX;
		}

		/**
		* For ACTION_DRAG_LOCATION and ACTION_DROP events, returns the y coordinate of the
		* drag point.
		* @return The current drag point's y coordinate, when relevant.
		* Gets the Y coordinate of the drag point. The value is valid if the
		* event action is {@link #ACTION_DRAG_ENTERED}, {@link #ACTION_DRAG_LOCATION},
		* {@link #ACTION_DROP}, or {@link #ACTION_DRAG_EXITED}.
		* @return The current drag point's Y coordinate
		*/
		public float getY() {
		return mY;
		}

		/**
		* Provides the data payload of the drag operation. This payload is only available
		* for events whose action value is ACTION_DROP.
		* @return The ClipData containing the data being dropped on the view.
		* Returns the {@link android.content.ClipData} object sent to the system as part of the call
		* to
		* {@link android.view.View#startDrag(ClipData,View.DragShadowBuilder,Object,int) startDrag()}.
		* This method only returns valid data if the event action is {@link #ACTION_DROP}.
		* @return The ClipData sent to the system by startDrag().
		*/
		public ClipData getClipData() {
		return mClipData;
		}

		/**
		* Provides a description of the drag operation's data payload. This payload is
		* available for all DragEvents other than ACTION_DROP.
		* @return A ClipDescription describing the contents of the data being dragged.
		* Returns the {@link android.content.ClipDescription} object contained in the
		* {@link android.content.ClipData} object sent to the system as part of the call to
		* {@link android.view.View#startDrag(ClipData,View.DragShadowBuilder,Object,int) startDrag()}.
		* The drag handler or listener for a View can use the metadata in this object to decide if the
		* View can accept the dragged View object's data.
		* <p>
		* This method returns valid data for all event actions.
		* @return The ClipDescription that was part of the ClipData sent to the system by startDrag().
		*/
		public ClipDescription getClipDescription() {
		return mClipDescription;
		}

		/**
		* Provides the local state object passed as the {@code myLocalState} parameter to
		* View.startDrag(). The object will always be null here if the application receiving
		* the DragEvent is not the one that started the drag.
		* Returns the local state object sent to the system as part of the call to
		* {@link android.view.View#startDrag(ClipData,View.DragShadowBuilder,Object,int) startDrag()}.
		* The object is intended to provide local information about the drag and drop operation. For
		* example, it can indicate whether the drag and drop operation is a copy or a move.
		* <p>
		* This method returns valid data for all event actions.
		* </p>
		* @return The local state object sent to the system by startDrag().
		*/
		public Object getLocalState() {
		return mLocalState;
		}

		/**
		* Provides an indication of whether the drag operation concluded successfully.
		* This method is only available on ACTION_DRAG_ENDED events.
		* @return {@code true} if the drag operation ended with an accepted drop; {@code false}
		* otherwise.
		* <p>
		* Returns an indication of the result of the drag and drop operation.
		* This method only returns valid data if the action type is {@link #ACTION_DRAG_ENDED}.
		* The return value depends on what happens after the user releases the drag shadow.
		* </p>
		* <p>
		* If the user releases the drag shadow on a View that can accept a drop, the system sends an
		* {@link #ACTION_DROP} event to the View object's drag event listener. If the listener
		* returns {@code true}, then getResult() will return {@code true}.
		* If the listener returns {@code false}, then getResult() returns {@code false}.
		* </p>
		* <p>
		* Notice that getResult() also returns {@code false} if no {@link #ACTION_DROP} is sent. This
		* happens, for example, when the user releases the drag shadow over an area outside of the
		* application. In this case, the system sends out {@link #ACTION_DRAG_ENDED} for the current
		* operation, but never sends out {@link #ACTION_DROP}.
		* </p>
		* @return {@code true} if a drag event listener returned {@code true} in response to
		* {@link #ACTION_DROP}. If the system did not send {@link #ACTION_DROP} before
		* {@link #ACTION_DRAG_ENDED}, or if the listener returned {@code false} in response to
		* {@link #ACTION_DROP}, then {@code false} is returned.
		*/
		public boolean getResult() {
		return mDragResult;
		@@ -271,6 +425,11 @@ public static final int ACTION_DRAG_EXITED = 6;
		}
		}

		/**
		* Returns a string containing a concise, human-readable representation of this DragEvent
		* object.
		* @return A string representation of the DragEvent object.
		*/
		@Override
		public String toString() {
		return "DragEvent{" + Integer.toHexString(System.identityHashCode(this))
		@@ -281,10 +440,20 @@ public static final int ACTION_DRAG_EXITED = 6;

		/* Parcelable interface */

		/**
		* Returns information about the {@link android.os.Parcel} representation of this DragEvent
		* object.
		* @return Information about the {@link android.os.Parcel} representation.
		*/
		public int describeContents() {
		return 0;
		}

		/**
		* Creates a {@link android.os.Parcel} object from this DragEvent object.
		* @param dest A {@link android.os.Parcel} object in which to put the DragEvent object.
		* @param flags Flags to store in the Parcel.
		*/
		public void writeToParcel(Parcel dest, int flags) {
		dest.writeInt(mAction);
		dest.writeFloat(mX);
		@@ -304,6 +473,9 @@ public static final int ACTION_DRAG_EXITED = 6;
		}
		}

		/**
		* A container for creating a DragEvent from a Parcel.
		*/
		public static final Parcelable.Creator<DragEvent> CREATOR =
		new Parcelable.Creator<DragEvent>() {
		public DragEvent createFromParcel(Parcel in) {

core/java/android/view/View.java

+256 −216

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