| /******************************************************************************* |
| * Copyright (c) 2000, 2011 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.swt.dnd; |
| |
| import org.eclipse.swt.internal.SWTEventListener; |
| |
| /** |
| * The <code>DropTargetListener</code> class provides event notification to the application |
| * for DropTarget events. |
| * |
| * <p>As the user moves the cursor into, over and out of a Control that has been designated |
| * as a DropTarget, events indicate what operation can be performed and what data can be |
| * transferred if a drop where to occur at that point. |
| * The application can respond to these events and change the type of data that will |
| * be dropped by modifying event.currentDataType, or change the operation that will be performed |
| * by modifying the event.detail field or stop any drop from happening on the current target |
| * by setting the event.detail field to DND_DROP_NONE.</p> |
| * |
| * <p>When the user causes a drop to happen by releasing the mouse over a valid drop target, |
| * the application has one last chance to change the data type of the drop through the |
| * DropAccept event. If the drop is still allowed, the DropAccept event is immediately |
| * followed by the Drop event. In the Drop event, the application can still change the |
| * operation that is performed but the data type is fixed.</p> |
| * |
| * @see DropTargetEvent |
| * |
| */ |
| public interface DropTargetListener extends SWTEventListener { |
| |
| /** |
| * The cursor has entered the drop target boundaries. |
| * |
| * <p>The following fields in the DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in)dataTypes |
| * <li>(in,out)currentDataType |
| * <li>(in)operations |
| * <li>(in,out)detail |
| * <li>(in,out)feedback |
| * </ul></p> |
| * |
| * <p>The <code>operations</code> value is determined by the modifier keys pressed by the user. |
| * If no keys are pressed the <code>event.detail</code> field is set to DND.DROP_DEFAULT. |
| * If the application does not set the <code>event.detail</code> to something other |
| * than <code>DND.DROP_DEFAULT</code> the operation will be set to the platform defined standard |
| * default.</p> |
| * |
| * <p>The <code>currentDataType</code> is determined by the first transfer agent specified in |
| * setTransfer() that matches a data type provided by the drag source.</p> |
| * |
| * <p>It is possible to get a DragEnter event when the drag source does not provide any matching data. |
| * In this case, the default operation is DND.DROP_NONE and the currentDataType is null.</p> |
| * |
| * <p>The application can change the operation that will be performed by modifying the |
| * <code>detail</code> field but the choice must be one of the values in the <code>operations</code> |
| * field or DND.DROP_NONE.</p> |
| * |
| * <p>The application can also change the type of data being requested by |
| * modifying the <code>currentDataTypes</code> field but the value must be one of the values |
| * in the <code>dataTypes</code> list.</p> |
| * |
| * @param event the information associated with the drag enter event |
| * |
| * @see DropTargetEvent |
| */ |
| public void dragEnter(DropTargetEvent event); |
| |
| /** |
| * The cursor has left the drop target boundaries OR the drop has been cancelled OR the data |
| * is about to be dropped. |
| * |
| * <p>The following fields in the DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in)dataTypes |
| * <li>(in)currentDataType |
| * <li>(in)operations |
| * <li>(in)detail |
| * </ul></p> |
| * |
| * @param event the information associated with the drag leave event |
| * |
| * @see DropTargetEvent |
| */ |
| public void dragLeave(DropTargetEvent event); |
| |
| /** |
| * The operation being performed has changed (usually due to the user changing the selected modifier key(s) |
| * while dragging). |
| * |
| * <p>The following fields in the DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in)dataTypes |
| * <li>(in,out)currentDataType |
| * <li>(in)operations |
| * <li>(in,out)detail |
| * <li>(in,out)feedback |
| * </ul></p> |
| * |
| * <p>The <code>operations</code> value is determined by the modifier keys pressed by the user. |
| * If no keys are pressed the <code>event.detail</code> field is set to DND.DROP_DEFAULT. |
| * If the application does not set the <code>event.detail</code> to something other than |
| * <code>DND.DROP_DEFAULT</code> the operation will be set to the platform defined standard default.</p> |
| * |
| * <p>The <code>currentDataType</code> value is determined by the value assigned to |
| * <code>currentDataType</code> in previous dragEnter and dragOver calls.</p> |
| * |
| * <p>The application can change the operation that will be performed by modifying the |
| * <code>detail</code> field but the choice must be one of the values in the <code>operations</code> |
| * field.</p> |
| * |
| * <p>The application can also change the type of data being requested by modifying |
| * the <code>currentDataTypes</code> field but the value must be one of the values in the |
| * <code>dataTypes</code> list.</p> |
| * |
| * @param event the information associated with the drag operation changed event |
| * |
| * @see DropTargetEvent |
| */ |
| public void dragOperationChanged(DropTargetEvent event); |
| |
| /** |
| * The cursor is moving over the drop target. |
| * |
| * <p>The following fields in the DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in)dataTypes |
| * <li>(in,out)currentDataType |
| * <li>(in)operations |
| * <li>(in,out)detail |
| * <li>(in,out)feedback |
| * </ul></p> |
| * |
| * <p>The <code>operations</code> value is determined by the value assigned to |
| * <code>currentDataType</code> in previous dragEnter and dragOver calls.</p> |
| * |
| * <p>The <code>currentDataType</code> value is determined by the value assigned to |
| * <code>currentDataType</code> in previous dragEnter and dragOver calls.</p> |
| * |
| * <p>The application can change the operation that will be performed by modifying the |
| * <code>detail</code> field but the choice must be one of the values in the <code>operations</code> |
| * field.</p> |
| * |
| * <p>The application can also change the type of data being requested by modifying the |
| * <code>currentDataTypes</code> field but the value must be one of the values in the |
| * <code>dataTypes</code> list.</p> |
| * |
| * <p>NOTE: At this point the <code>data</code> field is null. On some platforms, it is possible |
| * to obtain the data being transferred before the transfer occurs but in most platforms this is |
| * not possible. On those platforms where the data is available, the application can access the |
| * data as follows:</p> |
| * |
| * <pre><code> |
| * public void dragOver(DropTargetEvent event) { |
| * TextTransfer textTransfer = TextTransfer.getInstance(); |
| * String data = (String)textTransfer.nativeToJava(event.currentDataType); |
| * if (data != null) { |
| * System.out.println("Data to be dropped is (Text)"+data); |
| * } |
| * }; |
| * </code></pre> |
| * |
| * @param event the information associated with the drag over event |
| * |
| * @see DropTargetEvent |
| */ |
| public void dragOver(DropTargetEvent event); |
| |
| /** |
| * The data is being dropped. The data field contains java format of the data being dropped. |
| * To determine the type of the data object, refer to the documentation for the Transfer subclass |
| * specified in event.currentDataType. |
| * |
| * <p>The following fields in DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in,out)detail |
| * <li>(in)currentDataType |
| * <li>(in)data |
| * </ul></p> |
| * |
| * <p>The application can refuse to perform the drop operation by setting the detail |
| * field to DND.DROP_NONE.</p> |
| * |
| * @param event the information associated with the drop event |
| * |
| * @see DropTargetEvent |
| */ |
| public void drop(DropTargetEvent event); |
| |
| /** |
| * The drop is about to be performed. |
| * The drop target is given a last chance to change the nature of the drop. |
| * |
| * <p>The following fields in the DropTargetEvent apply: |
| * <ul> |
| * <li>(in)widget |
| * <li>(in)time |
| * <li>(in)x |
| * <li>(in)y |
| * <li>(in)dataTypes |
| * <li>(in,out)currentDataType |
| * <li>(in)operations |
| * <li>(in,out)detail |
| * </ul></p> |
| * |
| * <p>The application can veto the drop by setting the <code>event.detail</code> field to |
| * <code>DND.DROP_NONE</code>.</p> |
| * |
| * <p>The application can change the operation that will be performed by modifying the |
| * <code>detail</code> field but the choice must be one of the values in the |
| * <code>operations</code> field.</p> |
| * |
| * <p>The application can also change the type of data being requested by modifying the |
| * <code>currentDataTypes</code> field but the value must be one of the values in the < |
| * code>dataTypes</code> list.</p> |
| * |
| * @param event the information associated with the drop accept event |
| * |
| * @see DropTargetEvent |
| */ |
| public void dropAccept(DropTargetEvent event); |
| |
| } |