Drag and Drop example snippet: drag leaf items in a tree
/*
* Drag and Drop example snippet: drag leaf items in a tree
*
* For a list of all SWT example snippets see
* http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/dev.html#snippets
*/
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.DragSourceListener;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetAdapter;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
public class Snippet91 {
public static void main(String[] args) {
final Display display = new Display();
final Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
final Tree tree = new Tree(shell, SWT.BORDER);
for (int i = 0; i < 3; i++) {
TreeItem item = new TreeItem(tree, SWT.NONE);
item.setText("item " + i);
for (int j = 0; j < 3; j++) {
TreeItem subItem = new TreeItem(item, SWT.NONE);
subItem.setText("item " + i + " " + j);
for (int k = 0; k < 3; k++) {
TreeItem subsubItem = new TreeItem(subItem, SWT.NONE);
subsubItem.setText("item " + i + " " + j + " " + k);
}
}
}
Transfer[] types = new Transfer[] { TextTransfer.getInstance() };
int operations = DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK;
final DragSource source = new DragSource(tree, operations);
source.setTransfer(types);
final TreeItem[] dragSourceItem = new TreeItem[1];
source.addDragListener(new DragSourceListener() {
public void dragStart(DragSourceEvent event) {
TreeItem[] selection = tree.getSelection();
if (selection.length > 0 && selection[0].getItemCount() == 0) {
event.doit = true;
dragSourceItem[0] = selection[0];
} else {
event.doit = false;
}
};
public void dragSetData(DragSourceEvent event) {
event.data = dragSourceItem[0].getText();
}
public void dragFinished(DragSourceEvent event) {
if (event.detail == DND.DROP_MOVE)
dragSourceItem[0].dispose();
dragSourceItem[0] = null;
}
});
DropTarget target = new DropTarget(tree, operations);
target.setTransfer(types);
target.addDropListener(new DropTargetAdapter() {
public void dragOver(DropTargetEvent event) {
event.feedback = DND.FEEDBACK_EXPAND | DND.FEEDBACK_SCROLL;
if (event.item != null) {
TreeItem item = (TreeItem) event.item;
Point pt = display.map(null, tree, event.x, event.y);
Rectangle bounds = item.getBounds();
if (pt.y < bounds.y + bounds.height / 3) {
event.feedback |= DND.FEEDBACK_INSERT_BEFORE;
} else if (pt.y > bounds.y + 2 * bounds.height / 3) {
event.feedback |= DND.FEEDBACK_INSERT_AFTER;
} else {
event.feedback |= DND.FEEDBACK_SELECT;
}
}
}
public void drop(DropTargetEvent event) {
if (event.data == null) {
event.detail = DND.DROP_NONE;
return;
}
String text = (String) event.data;
if (event.item == null) {
TreeItem item = new TreeItem(tree, SWT.NONE);
item.setText(text);
} else {
TreeItem item = (TreeItem) event.item;
Point pt = display.map(null, tree, event.x, event.y);
Rectangle bounds = item.getBounds();
TreeItem parent = item.getParentItem();
if (parent != null) {
TreeItem[] items = parent.getItems();
int index = 0;
for (int i = 0; i < items.length; i++) {
if (items[i] == item) {
index = i;
break;
}
}
if (pt.y < bounds.y + bounds.height / 3) {
TreeItem newItem = new TreeItem(parent, SWT.NONE,
index);
newItem.setText(text);
} else if (pt.y > bounds.y + 2 * bounds.height / 3) {
TreeItem newItem = new TreeItem(parent, SWT.NONE,
index + 1);
newItem.setText(text);
} else {
TreeItem newItem = new TreeItem(item, SWT.NONE);
newItem.setText(text);
}
} else {
TreeItem[] items = tree.getItems();
int index = 0;
for (int i = 0; i < items.length; i++) {
if (items[i] == item) {
index = i;
break;
}
}
if (pt.y < bounds.y + bounds.height / 3) {
TreeItem newItem = new TreeItem(tree, SWT.NONE,
index);
newItem.setText(text);
} else if (pt.y > bounds.y + 2 * bounds.height / 3) {
TreeItem newItem = new TreeItem(tree, SWT.NONE,
index + 1);
newItem.setText(text);
} else {
TreeItem newItem = new TreeItem(item, SWT.NONE);
newItem.setText(text);
}
}
}
}
});
shell.setSize(400, 400);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
}
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