Drag and drop for tableviewer in SWT - drag-and-drop

Question

I need to Drag tableViewer cell value to another tableViewer cell in swt.
I need to remove that value where i dragged and add those value where i dropped in tableViewer i'm able to drag and drop but not able to drop where i want too and not able to remove and add value when i drag and drop in tableviewer. Here is the i have:Thank in advance for help.
public void DragandDrop(){
Transfer[] types = new Transfer[] { TextTransfer.getInstance() };
DragSource source = new DragSource(table_2, DND.DROP_MOVE | DND.DROP_COPY);
source.setTransfer(types);
source.addDragListener(new DragSourceAdapter() {
public void dragSetData(DragSourceEvent event) {
DragSource ds = (DragSource) event.widget;
Table table = (Table) ds.getControl();
TableItem[] selection = table.getSelection();
StringBuffer buff = new StringBuffer();
for (int i = 0, n = selection.length; i < n; i++) {
buff.append(selection[i].getText());
}
event.data = buff.toString();
}
});
DropTarget target = new DropTarget(table_3, DND.DROP_MOVE | DND.DROP_COPY );
target.setTransfer(types);
target.addDropListener(new DropTargetAdapter() {
public void dragEnter(DropTargetEvent event) {
if (event.detail != DND.DROP_DEFAULT) {
event.detail = (event.operations & DND.DROP_COPY) != 0 ? DND.DROP_COPY : DND.DROP_NONE;
}
for (int i = 0, n = event.dataTypes.length; i < n; i++) {
if (TextTransfer.getInstance().isSupportedType(event.dataTypes[i])) {
event.currentDataType = event.dataTypes[i];
}
}
}
public void dragOver(DropTargetEvent event) {
event.feedback = DND.FEEDBACK_SELECT | DND.FEEDBACK_SCROLL;
}
public void drop(DropTargetEvent event) {
if (TextTransfer.getInstance().isSupportedType(event.currentDataType)) {
DropTarget target = (DropTarget) event.widget;
Table table = (Table) target.getControl();
String data = (String) event.data;
TableItem item = new TableItem(table, SWT.NONE);
item.setText(new String[] { data });
// table.redraw();
}
}
});
}

Answer 1

to remove the selected value you can use follows
public void drop(DropTargetEvent event) {
if (TextTransfer.getInstance().isSupportedType(event.currentDataType)) {
DropTarget target = (DropTarget) event.widget;
Table table = (Table) target.getControl();
String data = (String) event.data;
TableItem item = new TableItem(table, SWT.NONE);
item.setText(new String[] { data });
//remove the tableitem you drag
table.remove(table.getSelectionIndex());
}

Answer 2

I was looking for Drag and Drop on TableViewer and found the solutions. Hope everyone understand easily. My case, I created two new Listener class inheritance from DragSourceListener & DropTargetListener. Because I want to use TableViewer functions. You need three things to do.
First save index of source item from void dragStart(DragSourceEvent event),
Seconds set data into event.data and
Then Last found target index from void drop(DropTargetEvent event).
public class TestClass extends TableViewer {
private int sourceIndex;
priavte class DragListener implements DragSourceListener {
private TableViewer viewer;
public ItemDragListener(TableViewer viewer) {
this.viewer = viewer;
}
public void dragStart(DragSourceEvent event) {
sourceIndex = viewer.getTable().getSelectionIndex();
}
public void dragSetData(DragSourceEvent event) {
// save data
ISelection select = viewer.getSelection();
if (select instanceof IStructuredSelection) {
Object item = (Object) ((IStructuredSelection)select).getFirstElement();
// save item to event.data
event.data = .........
}
:
}
private class ItemDropListener implements DropTargetListener {
TableViewer viewer;
public ItemDropListener(TableViewer viewer) {
this.viewer = viewer;
}
public void drop(DropTargetEvent event) {
if (TextTransfer.getInstance().isSupportedType(event.currentDataType)) {
TableItem item = (TableItem)event.item;
int targetIndex= -1;
if (item != null) {
Table table = item.getParent();
targetIndex= table.indexOf(item);
}
String data = (String) event.data;
// add an item
if (targetIndex >= 0)
viewer.insert((Object)data, targetIndex);
else
viewer.add((Object)data);
// remove an item
viewer.getTable().remove(sourceIndex); // Careful, it can be changed after add an item
}
}
public void init() {
Transfer[] transfers = new Transfer[] { TextTransfer.getInstance() };
this.addDragSupport(DND.DROP_COPY | DND.DROP_MOVE, transfers, new ItemDragListener(this));
this.addDropSupport(DND.DROP_COPY | DND.DROP_MOVE, transfers, new ItemDropListener(this));
}
}