| /******************************************************************************* |
| * Copyright (c) 2000, 2003 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Common Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.swt.dnd; |
| |
| import org.eclipse.swt.*; |
| import org.eclipse.swt.internal.ole.win32.*; |
| import org.eclipse.swt.graphics.*; |
| import org.eclipse.swt.widgets.*; |
| import org.eclipse.swt.internal.win32.*; |
| |
| /** |
| * |
| * Class <code>DropTarget</code> defines the target object for a drag and drop transfer. |
| * |
| * IMPORTANT: This class is <em>not</em> intended to be subclassed. |
| * |
| * <p>This class identifies the <code>Control</code> over which the user must position the cursor |
| * in order to drop the data being transferred. It also specifies what data types can be dropped on |
| * this control and what operations can be performed. You may have several DropTragets in an |
| * application but there can only be a one to one mapping between a <code>Control</code> and a <code>DropTarget</code>. |
| * The DropTarget can receive data from within the same application or from other applications |
| * (such as text dragged from a text editor like Word).</p> |
| * |
| * <code><pre> |
| * int operations = DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK; |
| * Transfer[] types = new Transfer[] {TextTransfer.getInstance()}; |
| * DropTarget target = new DropTarget(label, operations); |
| * target.setTransfer(types); |
| * </code></pre> |
| * |
| * <p>The application is notified of data being dragged over this control and of when a drop occurs by |
| * implementing the interface <code>DropTargetListener</code> which uses the class |
| * <code>DropTargetEvent</code>. The application can modify the type of drag being performed |
| * on this Control at any stage of the drag by modifying the <code>event.detail</code> field or the |
| * <code>event.currentDataType</code> field. When the data is dropped, it is the responsibility of |
| * the application to copy this data for its own purposes. |
| * |
| * <code><pre> |
| * target.addDropListener (new DropTargetListener() { |
| * public void dragEnter(DropTargetEvent event) {}; |
| * public void dragOver(DropTargetEvent event) {}; |
| * public void dragLeave(DropTargetEvent event) {}; |
| * public void dragOperationChanged(DropTargetEvent event) {}; |
| * public void dropAccept(DropTargetEvent event) {} |
| * public void drop(DropTargetEvent event) { |
| * // A drop has occurred, copy over the data |
| * if (event.data == null) { // no data to copy, indicate failure in event.detail |
| * event.detail = DND.DROP_NONE; |
| * return; |
| * } |
| * label.setText ((String) event.data); // data copied to label text |
| * } |
| * }); |
| * </pre></code> |
| * |
| * <dl> |
| * <dt><b>Styles</b></dt> <dd>DND.DROP_NONE, DND.DROP_COPY, DND.DROP_MOVE, DND.DROP_LINK</dd> |
| * <dt><b>Events</b></dt> <dd>DND.DragEnter, DND.DragLeave, DND.DragOver, DND.DragOperationChanged, |
| * DND.DropAccept, DND.Drop </dd> |
| * </dl> |
| */ |
| public class DropTarget extends Widget { |
| |
| |
| // interfaces |
| private COMObject iDropTarget; |
| |
| // info for registering as a droptarget |
| private Control control; |
| private Listener controlListener; |
| |
| private Transfer[] transferAgents = new Transfer[0]; |
| |
| private int refCount; |
| |
| // info about data being dragged over site |
| private TransferData selectedDataType; |
| private TransferData[] dataTypes; |
| private int lastOperation; |
| private int keyState; |
| |
| private DragUnderEffect effect; |
| |
| private int iDataObject; |
| |
| private static final String DROPTARGETID = "DropTarget"; //$NON-NLS-1$ |
| /** |
| * Creates a new <code>DropTarget</code> to allow data to be dropped on the specified |
| * <code>Control</code>. |
| * Creating an instance of a DropTarget may cause system resources to be allocated |
| * depending on the platform. It is therefore mandatory that the DropTarget instance |
| * be disposed when no longer required. |
| * |
| * @param control the <code>Control</code> over which the user positions the cursor to drop the data |
| * @param style the bitwise OR'ing of allowed operations; this may be a combination of any of |
| * DND.DROP_NONE, DND.DROP_COPY, DND.DROP_MOVE, DND.DROP_LINK |
| * |
| * @exception SWTException <ul> |
| * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> |
| * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> |
| * @exception SWTError <ul> |
| * <li>ERROR_CANNOT_INIT_DROP - unable to initiate drop target</li> |
| * </ul> |
| * |
| * @see DropTarget#dispose |
| * @see DropTarget#checkSubclass |
| * @see DND#DROP_NONE |
| * @see DND#DROP_COPY |
| * @see DND#DROP_MOVE |
| * @see DND#DROP_LINK |
| */ |
| public DropTarget(Control control, int style) { |
| |
| super (control, checkStyle(style)); |
| this.control = control; |
| if (control.getData(DROPTARGETID) != null) |
| DND.error(DND.ERROR_CANNOT_INIT_DROP); |
| control.setData(DROPTARGETID, this); |
| createCOMInterfaces(); |
| this.AddRef(); |
| |
| int result = 0; |
| if ((result = COM.CoLockObjectExternal(iDropTarget.getAddress(), true, true)) != COM.S_OK) |
| DND.error(DND.ERROR_CANNOT_INIT_DROP, result); |
| if ((result = COM.RegisterDragDrop( control.handle, iDropTarget.getAddress() )) != COM.S_OK) |
| DND.error(DND.ERROR_CANNOT_INIT_DROP, result); |
| |
| controlListener = new Listener () { |
| public void handleEvent (Event event) { |
| DropTarget.this.dispose(); |
| } |
| }; |
| |
| control.addListener (SWT.Dispose, controlListener); |
| |
| this.addListener (SWT.Dispose, new Listener () { |
| public void handleEvent (Event event) { |
| onDispose(); |
| } |
| }); |
| |
| if (control instanceof Tree) { |
| effect = new TreeDragUnderEffect((Tree)control); |
| } else if (control instanceof Table) { |
| effect = new TableDragUnderEffect((Table)control); |
| } else { |
| effect = new NoDragUnderEffect(control); |
| } |
| } |
| /** |
| * Adds the listener to the collection of listeners who will |
| * be notified when a drag and drop operation is in progress, by sending |
| * it one of the messages defined in the <code>DropTargetListener</code> |
| * interface. |
| * |
| * <p><ul> |
| * <li><code>dragEnter</code> is called when the cursor has entered the drop target boundaries |
| * <li><code>dragLeave</code> is called when the cursor has left the drop target boundaries and just before |
| * the drop occurs or is cancelled. |
| * <li><code>dragOperationChanged</code> is called when the operation being performed has changed |
| * (usually due to the user changing the selected modifier key(s) while dragging) |
| * <li><code>dragOver</code> is called when the cursor is moving over the drop target |
| * <li><code>dropAccept</code> is called just before the drop is performed. The drop target is given |
| * the chance to change the nature of the drop or veto the drop by setting the <code>event.detail</code> field |
| * <li><code>drop</code> is called when the data is being dropped |
| * </ul></p> |
| * |
| * @param listener the listener which should be notified |
| * |
| * @exception IllegalArgumentException <ul> |
| * <li>ERROR_NULL_ARGUMENT - if the listener is null</li> |
| * </ul> |
| * @exception SWTException <ul> |
| * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> |
| * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> |
| * </ul> |
| * |
| * @see DropTargetListener |
| * @see #removeDropListener |
| * @see DropTargetEvent |
| */ |
| public void addDropListener(DropTargetListener listener) { |
| if (listener == null) DND.error (SWT.ERROR_NULL_ARGUMENT); |
| DNDListener typedListener = new DNDListener (listener); |
| addListener (DND.DragEnter, typedListener); |
| addListener (DND.DragLeave, typedListener); |
| addListener (DND.DragOver, typedListener); |
| addListener (DND.DragOperationChanged, typedListener); |
| addListener (DND.Drop, typedListener); |
| addListener (DND.DropAccept, typedListener); |
| |
| } |
| private int AddRef() { |
| refCount++; |
| return refCount; |
| } |
| static int checkStyle (int style) { |
| if (style == SWT.NONE) return DND.DROP_MOVE; |
| return style; |
| } |
| private void createCOMInterfaces() { |
| // register each of the interfaces that this object implements |
| iDropTarget = new COMObject(new int[]{2, 0, 0, 5, 4, 0, 5}){ |
| public int method0(int[] args) {return QueryInterface(args[0], args[1]);} |
| public int method1(int[] args) {return AddRef();} |
| public int method2(int[] args) {return Release();} |
| public int method3(int[] args) {return DragEnter(args[0], args[1], args[2], args[3], args[4]);} |
| public int method4(int[] args) {return DragOver(args[0], args[1], args[2], args[3]);} |
| public int method5(int[] args) {return DragLeave();} |
| public int method6(int[] args) {return Drop(args[0], args[1], args[2], args[3], args[4]);} |
| }; |
| |
| } |
| private void onDispose () { |
| if (control == null) return; |
| |
| COM.RevokeDragDrop(control.handle); |
| |
| if (controlListener != null) |
| control.removeListener(SWT.Dispose, controlListener); |
| controlListener = null; |
| control.setData(DROPTARGETID, null); |
| transferAgents = null; |
| control = null; |
| |
| COM.CoLockObjectExternal(iDropTarget.getAddress(), false, true); |
| |
| this.Release(); |
| |
| COM.CoFreeUnusedLibraries(); |
| } |
| private void disposeCOMInterfaces() { |
| if (iDropTarget != null) |
| iDropTarget.dispose(); |
| iDropTarget = null; |
| } |
| private int DragEnter( |
| int pDataObject, //Pointer to the interface of the source data object |
| int grfKeyState, //Current state of keyboard modifier keys |
| int pt_x, //Current cursor coordinates |
| int pt_y, //Current cursor coordinates |
| int pdwEffect //Pointer to the effect of the drag-and-drop operation |
| ){ |
| |
| selectedDataType = null; |
| dataTypes = new TransferData[0]; |
| iDataObject = 0; |
| |
| // Are any types being dragged for which we have a matching transfer object? |
| // Get enumerator of dragged types |
| IDataObject dataObject = new IDataObject(pDataObject); |
| dataObject.AddRef(); |
| int[] address = new int[1]; |
| if (dataObject.EnumFormatEtc(COM.DATADIR_GET, address) != COM.S_OK){ |
| OS.MoveMemory(pdwEffect, new int[] {COM.DROPEFFECT_NONE}, 4); |
| dataObject.Release(); |
| return COM.S_OK; |
| } |
| IEnumFORMATETC enum = new IEnumFORMATETC(address[0]); |
| dataObject.Release(); |
| iDataObject = pDataObject; |
| |
| // Loop over enumerator and save any types that match what we are looking for |
| int rgelt = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, FORMATETC.sizeof); |
| int[] pceltFetched = new int[1]; |
| enum.Reset(); |
| while (enum.Next(1, rgelt, pceltFetched) == COM.S_OK && pceltFetched[0] == 1) { |
| TransferData transferData = new TransferData(); |
| transferData.formatetc = new FORMATETC(); |
| COM.MoveMemory(transferData.formatetc, rgelt, FORMATETC.sizeof); |
| transferData.type = transferData.formatetc.cfFormat; |
| |
| for (int i = 0; i < transferAgents.length; i++){ |
| if (transferAgents[i].isSupportedType(transferData)){ |
| TransferData[] newDataTypes = new TransferData[dataTypes.length + 1]; |
| System.arraycopy(dataTypes, 0, newDataTypes, 0, dataTypes.length); |
| newDataTypes[dataTypes.length] = transferData; |
| dataTypes = newDataTypes; |
| break; |
| } |
| } |
| } |
| OS.GlobalFree(rgelt); |
| enum.Release(); |
| |
| // give listeners a chance to have input |
| DNDEvent event = new DNDEvent(); |
| event.widget = this; |
| event.time = OS.GetMessageTime(); |
| event.x = pt_x; |
| event.y = pt_y; |
| event.dataTypes = dataTypes; |
| event.feedback = DND.FEEDBACK_SELECT; |
| int[] allowedEffects = new int[1]; |
| OS.MoveMemory(allowedEffects, pdwEffect, 4); |
| allowedEffects[0] = osToOp(allowedEffects[0]); |
| event.operations = allowedEffects[0]; |
| if (dataTypes.length > 0) { |
| event.dataType = dataTypes[0]; |
| event.dataType.pIDataObject = pDataObject; |
| } |
| // assign operation if it is allowed |
| keyState = getOperationFromKeyState(grfKeyState); |
| int style = getStyle(); |
| if (keyState == DND.DROP_DEFAULT && (style & DND.DROP_DEFAULT) == 0) { |
| keyState = DND.DROP_MOVE; |
| } |
| event.detail = DND.DROP_NONE; |
| if ((keyState & style) == keyState){ |
| event.detail = keyState; |
| } |
| |
| try { |
| notifyListeners(DND.DragEnter,event); |
| } catch (Throwable e) { |
| OS.MoveMemory(pdwEffect, new int[] {COM.DROPEFFECT_NONE}, 4); |
| return COM.S_OK; |
| } |
| |
| if (event.detail == DND.DROP_DEFAULT) { |
| event.detail = DND.DROP_MOVE; |
| } |
| for (int i = 0; i < dataTypes.length; i++) { |
| if (dataTypes[i].equals(event.dataType)){ |
| selectedDataType = event.dataType; |
| break; |
| } |
| } |
| lastOperation = DND.DROP_NONE; |
| if (selectedDataType != null && ((allowedEffects[0] & event.detail) == event.detail)) { |
| lastOperation = event.detail; |
| } |
| |
| effect.show(event.feedback, event.x, event.y); |
| OS.MoveMemory(pdwEffect, new int[] {opToOs(lastOperation)}, 4); |
| return COM.S_OK; |
| } |
| private int DragLeave() |
| { |
| effect.show(DND.FEEDBACK_NONE, 0, 0); |
| keyState = DND.DROP_NONE; |
| |
| // give listeners a chance to react |
| DNDEvent event = new DNDEvent(); |
| event.widget = this; |
| event.time = OS.GetMessageTime(); |
| event.detail = DND.DROP_NONE; |
| try { |
| notifyListeners(DND.DragLeave, event); |
| } catch (Throwable e) {} |
| |
| return COM.S_OK; |
| } |
| private int DragOver( |
| int grfKeyState, //Current state of keyboard modifier keys |
| int pt_x, //Current cursor coordinates |
| int pt_y, |
| int pdwEffect //Pointer to the effect of the drag-and-drop operation |
| ){ |
| DNDEvent event = new DNDEvent(); |
| event.widget = this; |
| event.time = OS.GetMessageTime(); |
| event.x = pt_x; |
| event.y = pt_y; |
| event.dataTypes = dataTypes; |
| event.feedback = DND.FEEDBACK_SELECT; |
| int[] allowedEffects = new int[1]; |
| OS.MoveMemory(allowedEffects, pdwEffect, 4); |
| allowedEffects[0] = osToOp(allowedEffects[0]); |
| event.operations = allowedEffects[0]; |
| event.dataType = selectedDataType; |
| if (event.dataType != null) { |
| event.dataType.pIDataObject = iDataObject; |
| } |
| |
| int oldKeyState = keyState; |
| keyState = getOperationFromKeyState(grfKeyState); |
| int style = getStyle(); |
| if (keyState == DND.DROP_DEFAULT && (style & DND.DROP_DEFAULT) == 0) { |
| keyState = DND.DROP_MOVE; |
| } |
| try { |
| if (keyState == oldKeyState) { |
| event.detail = lastOperation; |
| notifyListeners(DND.DragOver,event); |
| } else { |
| event.detail = DND.DROP_NONE; |
| if ((keyState & style) == keyState){ |
| event.detail = keyState; |
| } |
| notifyListeners(DND.DragOperationChanged, event); |
| } |
| } catch (Throwable e) { |
| OS.MoveMemory(pdwEffect, new int[] {COM.DROPEFFECT_NONE}, 4); |
| return COM.S_OK; |
| } |
| if (event.detail == DND.DROP_DEFAULT) { |
| event.detail = DND.DROP_MOVE; |
| } |
| |
| // update drop data and drag under effect based on response from event |
| selectedDataType = null; |
| for (int i = 0; i < dataTypes.length; i++) { |
| if (dataTypes[i].equals(event.dataType)){ |
| selectedDataType = event.dataType; |
| break; |
| } |
| } |
| |
| lastOperation = DND.DROP_NONE; |
| if (selectedDataType != null && ((allowedEffects[0] & event.detail) == event.detail)) { |
| lastOperation = event.detail; |
| } |
| |
| effect.show(event.feedback, event.x, event.y); |
| OS.MoveMemory(pdwEffect, new int[] {opToOs(lastOperation)}, 4); |
| return COM.S_OK; |
| } |
| private int Drop( |
| int pDataObject, //Pointer to the interface for the source data |
| int grfKeyState, //Current state of keyboard modifier keys |
| int pt_x, //Current cursor coordinates |
| int pt_y, |
| int pdwEffect //Pointer to the effect of the drag-and-drop operation |
| ){ |
| |
| effect.show(DND.FEEDBACK_NONE, 0, 0); |
| keyState = DND.DROP_NONE; |
| |
| // Send a DragLeave event to be consistant with Motif |
| DNDEvent event = new DNDEvent(); |
| event.widget = this; |
| event.time = OS.GetMessageTime(); |
| event.detail = DND.DROP_NONE; |
| try { |
| notifyListeners(DND.DragLeave, event); |
| } catch (Throwable e) {} |
| |
| // Send a DropAccept event to be consistant with Motif |
| event = new DNDEvent(); |
| event.widget = this; |
| event.time = OS.GetMessageTime(); |
| event.x = pt_x; |
| event.y = pt_y; |
| event.dataTypes = dataTypes; |
| int[] allowedEffects = new int[1]; |
| OS.MoveMemory(allowedEffects, pdwEffect, 4); |
| allowedEffects[0] = osToOp(allowedEffects[0]); |
| event.operations = allowedEffects[0]; |
| event.dataType = selectedDataType; |
| if (event.dataType != null) { |
| event.dataType.pIDataObject = iDataObject; |
| } |
| event.detail = lastOperation; |
| |
| try { |
| notifyListeners(DND.DropAccept,event); |
| } catch (Throwable e) { |
| event.dataType = null; |
| event.detail = DND.DROP_NONE; |
| } |
| |
| selectedDataType = null; |
| for (int i = 0; i < dataTypes.length; i++) { |
| if (dataTypes[i].equals(event.dataType)){ |
| selectedDataType = event.dataType; |
| break; |
| } |
| } |
| lastOperation = DND.DROP_NONE; |
| if (selectedDataType != null && (allowedEffects[0] & event.detail) == event.detail) { |
| lastOperation = event.detail; |
| } |
| |
| if (lastOperation != DND.DROP_NONE){ |
| // find the matching converter |
| Transfer matchingTransfer = null; |
| for (int i = 0; i < transferAgents.length; i++){ |
| if (transferAgents[i].isSupportedType(event.dataType)){ |
| matchingTransfer = transferAgents[i]; |
| break; |
| } |
| } |
| if (matchingTransfer == null){ |
| lastOperation = DND.DROP_NONE; |
| } else { |
| event.dataType.pIDataObject = pDataObject; |
| Object data = matchingTransfer.nativeToJava(event.dataType); |
| event.data = data; |
| try { |
| notifyListeners(DND.Drop,event); |
| lastOperation = DND.DROP_NONE; |
| if ((allowedEffects[0] & event.detail) == event.detail) { |
| lastOperation = event.detail; |
| } |
| } catch (Throwable e) { |
| lastOperation = DND.DROP_NONE; |
| } |
| |
| } |
| } |
| OS.MoveMemory(pdwEffect, new int[] {opToOs(lastOperation)}, 4); |
| return COM.S_OK; |
| } |
| /** |
| * Returns the Control which is registered for this DropTarget. This is the control over which the |
| * user positions the cursor to drop the data. |
| * |
| * @return the Control which is registered for this DropTarget |
| */ |
| public Control getControl () { |
| return control; |
| } |
| public Display getDisplay () { |
| |
| if (control == null) DND.error(SWT.ERROR_WIDGET_DISPOSED); |
| return control.getDisplay (); |
| } |
| private int getOperationFromKeyState(int grfKeyState) { |
| boolean ctrl = (grfKeyState & OS.MK_CONTROL) != 0; |
| boolean shift = (grfKeyState & OS.MK_SHIFT) != 0; |
| if (ctrl && shift) { |
| // CTRL + SHIFT == Link |
| return DND.DROP_LINK; |
| } |
| if (ctrl){ |
| //CTRL == COPY |
| return DND.DROP_COPY; |
| } |
| if (shift){ |
| //CTRL == MOVE |
| return DND.DROP_MOVE; |
| } |
| |
| return DND.DROP_DEFAULT; // default operation |
| } |
| /** |
| * Returns a list of the data types that can be transferred to this DropTarget. |
| * |
| * @return a list of the data types that can be transferred to this DropTarget |
| */ |
| public Transfer[] getTransfer(){ |
| return transferAgents; |
| } |
| public void notifyListeners (int eventType, Event event) { |
| Point coordinates = new Point(event.x, event.y); |
| coordinates = control.toControl(coordinates); |
| if (this.control instanceof Tree) { |
| event.item = ((Tree)control).getItem(coordinates); |
| } |
| if (this.control instanceof Table) { |
| event.item = ((Table)control).getItem(coordinates); |
| } |
| super.notifyListeners(eventType, event); |
| } |
| private int opToOs(int operation) { |
| int osOperation = 0; |
| if ((operation & DND.DROP_COPY) != 0){ |
| osOperation |= COM.DROPEFFECT_COPY; |
| } |
| if ((operation & DND.DROP_LINK) != 0) { |
| osOperation |= COM.DROPEFFECT_LINK; |
| } |
| if ((operation & DND.DROP_MOVE) != 0) { |
| osOperation |= COM.DROPEFFECT_MOVE; |
| } |
| return osOperation; |
| } |
| private int osToOp(int osOperation){ |
| int operation = 0; |
| if ((osOperation & COM.DROPEFFECT_COPY) != 0){ |
| operation |= DND.DROP_COPY; |
| } |
| if ((osOperation & COM.DROPEFFECT_LINK) != 0) { |
| operation |= DND.DROP_LINK; |
| } |
| if ((osOperation & COM.DROPEFFECT_MOVE) != 0) { |
| operation |= DND.DROP_MOVE; |
| } |
| return operation; |
| |
| } |
| private int QueryInterface(int riid, int ppvObject) { |
| |
| if (riid == 0 || ppvObject == 0) |
| return COM.E_INVALIDARG; |
| GUID guid = new GUID(); |
| COM.MoveMemory(guid, riid, GUID.sizeof); |
| if (COM.IsEqualGUID(guid, COM.IIDIUnknown) || COM.IsEqualGUID(guid, COM.IIDIDropTarget)) { |
| COM.MoveMemory(ppvObject, new int[] {iDropTarget.getAddress()}, 4); |
| AddRef(); |
| return COM.S_OK; |
| } |
| |
| COM.MoveMemory(ppvObject, new int[] {0}, 4); |
| return COM.E_NOINTERFACE; |
| } |
| private int Release() { |
| refCount--; |
| |
| if (refCount == 0) { |
| disposeCOMInterfaces(); |
| COM.CoFreeUnusedLibraries(); |
| } |
| |
| return refCount; |
| } |
| /** |
| * Removes the listener from the collection of listeners who will |
| * be notified when a drag and drop operation is in progress. |
| * |
| * @param listener the listener which should be notified |
| * |
| * @exception IllegalArgumentException <ul> |
| * <li>ERROR_NULL_ARGUMENT - if the listener is null</li> |
| * </ul> |
| * @exception SWTException <ul> |
| * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> |
| * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> |
| * </ul> |
| * |
| * @see DropTargetListener |
| * @see #addDropListener |
| */ |
| public void removeDropListener(DropTargetListener listener) { |
| if (listener == null) DND.error (SWT.ERROR_NULL_ARGUMENT); |
| removeListener (DND.DragEnter, listener); |
| removeListener (DND.DragLeave, listener); |
| removeListener (DND.DragOver, listener); |
| removeListener (DND.DragOperationChanged, listener); |
| removeListener (DND.Drop, listener); |
| removeListener (DND.DropAccept, listener); |
| } |
| /** |
| * Specifies the data types that can be transferred to this DropTarget. If data is |
| * being dragged that does not match one of these types, the drop target will be notified of |
| * the drag and drop operation but the currentDataType will be null and the operation |
| * will be DND.NONE. |
| * |
| * @param transferAgents a list of Transfer objects which define the types of data that can be |
| * dropped on this target |
| * |
| * @exception IllegalArgumentException <ul> |
| * <li>ERROR_NULL_ARGUMENT - if transferAgents is null</li> |
| * </ul> |
| */ |
| public void setTransfer(Transfer[] transferAgents){ |
| if (transferAgents == null) DND.error(SWT.ERROR_NULL_ARGUMENT); |
| this.transferAgents = transferAgents; |
| } |
| |
| protected void checkSubclass () { |
| String name = getClass().getName (); |
| String validName = DropTarget.class.getName(); |
| if (!validName.equals(name)) { |
| DND.error (SWT.ERROR_INVALID_SUBCLASS); |
| } |
| } |
| } |