Drag leaf items in a tree : SWT Drag Drop « SWT « Java Tutorial






Drag leaf items in a tree
/*******************************************************************************
 * Copyright (c) 2000, 2004 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
 *******************************************************************************/

/*
 * Drag and Drop example snippet: drag leaf items in a tree
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/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 DragTreeLeaf {

  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();
  }
}








17.114.SWT Drag Drop
17.114.1.Dragging and Dropping
17.114.2.Drag selected text in Text to LabelDrag selected text in Text to Label
17.114.3.Drag and Drop inside TableDrag and Drop inside Table
17.114.4.Drag and Drop example snippet: determine data types available (win32 only)Drag and Drop example snippet: determine data types available (win32 only)
17.114.5.Drag and Drop: define a default operation (in this example, Copy)Drag and Drop: define a default operation (in this example, Copy)
17.114.6.Drag and Drop: define my own data transfer typeDrag and Drop: define my own data transfer type
17.114.7.Drag leaf items in a treeDrag leaf items in a tree
17.114.8.Drag text between two labelsDrag text between two labels
17.114.9.Drag and Drop: determine native data types available (motif only)
17.114.10.Make a dropped data type depend on a target item in tableMake a dropped data type depend on a target item in table