Source Code : SWT DND (Drag and Drop) comprehensive Example

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SWT DND (Drag and Drop) comprehensive Example

SWT DND (Drag and Drop) comprehensive Example 


import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.custom.ScrolledComposite;
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.DropTargetEvent;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.FileTransfer;
import org.eclipse.swt.dnd.HTMLTransfer;
import org.eclipse.swt.dnd.RTFTransfer;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class DNDExample {

  private int dragOperation = 0;

  private Transfer[] dragTypes = new Transfer[0];

  private Control dragControl;

  private int dragControlType = 0;

  private DragSource dragSource;

  private String dragDataText;

  private String dragDataRTF;

  private String dragDataHTML;

  private String[] dragDataFiles;

  private List fileList;

  private boolean dragEnabled = false;

  private int dropOperation = 0;

  private int dropFeedback = 0;

  private int dropDefaultOperation = 0;

  private Transfer[] dropTypes = new Transfer[0];

  private DropTarget dropTarget;

  private Control dropControl;

  private int dropControlType = 0;

  private Composite defaultParent;

  private boolean dropEnabled = false;

  private Text dragConsole;

  private boolean dragEventDetail = false;

  private Text dropConsole;

  private boolean dropEventDetail = false;

  private static final int BUTTON_TOGGLE = 0;

  private static final int BUTTON_RADIO = 1;

  private static final int BUTTON_CHECK = 2;

  private static final int CANVAS = 3;

  private static final int LABEL = 4;

  private static final int LIST = 5;

  private static final int TABLE = 6;

  private static final int TREE = 7;

  private static final int TEXT = 8;

  public static void main(String[] args) {
    Display display = new Display();
    DNDExample example = new DNDExample();
    example.open(display);
    display.dispose();
  }

  private void addDragTransfer(Transfer transfer) {
    Transfer[] newTypes = new Transfer[dragTypes.length + 1];
    System.arraycopy(dragTypes, 0, newTypes, 0, dragTypes.length);
    newTypes[dragTypes.length] = transfer;
    dragTypes = newTypes;
    if (dragSource != null) {
      dragSource.setTransfer(dragTypes);
    }
  }

  private void addDropTransfer(Transfer transfer) {
    Transfer[] newTypes = new Transfer[dropTypes.length + 1];
    System.arraycopy(dropTypes, 0, newTypes, 0, dropTypes.length);
    newTypes[dropTypes.length] = transfer;
    dropTypes = newTypes;
    if (dropTarget != null) {
      dropTarget.setTransfer(dropTypes);
    }
  }

  private void createDragOperations(Composite parent) {
    parent.setLayout(new RowLayout(SWT.VERTICAL));
    final Button moveButton = new Button(parent, SWT.CHECK);
    moveButton.setText("DND.DROP_MOVE");
    moveButton.setSelection(true);
    dragOperation = DND.DROP_MOVE;
    moveButton.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dragOperation |= DND.DROP_MOVE;
        } else {
          dragOperation = dragOperation & ~DND.DROP_MOVE;
          if (dragOperation == 0) {
            dragOperation = DND.DROP_MOVE;
            moveButton.setSelection(true);
          }
        }
        if (dragEnabled) {
          createDragSource();
        }
      }
    });

    Button b = new Button(parent, SWT.CHECK);
    b.setText("DND.DROP_COPY");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dragOperation |= DND.DROP_COPY;
        } else {
          dragOperation = dragOperation & ~DND.DROP_COPY;
          if (dragOperation == 0) {
            dragOperation = DND.DROP_MOVE;
            moveButton.setSelection(true);
          }
        }
        if (dragEnabled) {
          createDragSource();
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("DND.DROP_LINK");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dragOperation |= DND.DROP_LINK;
        } else {
          dragOperation = dragOperation & ~DND.DROP_LINK;
          if (dragOperation == 0) {
            dragOperation = DND.DROP_MOVE;
            moveButton.setSelection(true);
          }
        }
        if (dragEnabled) {
          createDragSource();
        }
      }
    });
  }

  private void createDragSource() {
    if (dragSource != null)
      dragSource.dispose();
    dragSource = new DragSource(dragControl, dragOperation);
    dragSource.setTransfer(dragTypes);
    dragSource.addDragListener(new DragSourceListener() {
      public void dragFinished(org.eclipse.swt.dnd.DragSourceEvent event) {
        dragConsole.append(">>dragFinished
");
        printEvent(event);
        dragDataText = dragDataRTF = dragDataHTML = null;
        dragDataFiles = null;
        if (event.detail == DND.DROP_MOVE) {
          switch (dragControlType) {
          case BUTTON_CHECK:
          case BUTTON_TOGGLE:
          case BUTTON_RADIO: {
            Button b = (Button) dragControl;
            b.setText("");
            break;
          }
          case TABLE: {
            Table table = (Table) dragControl;
            TableItem[] items = table.getSelection();
            for (int i = 0; i < items.length; i++) {
              items[i].dispose();
            }
            break;
          }
          case TEXT: {
            Text text = (Text) dragControl;
            text.clearSelection();
            break;
          }
          case TREE: {
            Tree tree = (Tree) dragControl;
            TreeItem[] items = tree.getSelection();
            for (int i = 0; i < items.length; i++) {
              items[i].dispose();
            }
            break;
          }
          case CANVAS: {
            dragControl.setData("STRINGS", null);
            dragControl.redraw();
            break;
          }
          case LABEL: {
            Label label = (Label) dragControl;
            label.setText("");
            break;
          }
          case LIST: {
            List list = (List) dragControl;
            int[] indices = list.getSelectionIndices();
            list.remove(indices);
            break;
          }
          }
        }
      }

      public void dragSetData(org.eclipse.swt.dnd.DragSourceEvent event) {
        dragConsole.append(">>dragSetData
");
        printEvent(event);
        if (TextTransfer.getInstance().isSupportedType(event.dataType)) {
          event.data = dragDataText;
        }
        if (RTFTransfer.getInstance().isSupportedType(event.dataType)) {
          event.data = dragDataRTF;
        }
        if (HTMLTransfer.getInstance().isSupportedType(event.dataType)) {
          event.data = dragDataHTML;
        }
        if (FileTransfer.getInstance().isSupportedType(event.dataType)) {
          event.data = dragDataFiles;
        }
      }

      public void dragStart(org.eclipse.swt.dnd.DragSourceEvent event) {
        dragConsole.append(">>dragStart
");
        printEvent(event);
        dragDataFiles = fileList.getItems();
        switch (dragControlType) {
        case BUTTON_CHECK:
        case BUTTON_TOGGLE:
        case BUTTON_RADIO: {
          Button b = (Button) dragControl;
          dragDataText = b.getSelection() ? "true" : "false";
          break;
        }
        case TABLE: {
          Table table = (Table) dragControl;
          TableItem[] items = table.getSelection();
          if (items.length == 0) {
            event.doit = false;
          } else {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < items.length; i++) {
              buffer.append(items[i].getText());
              if (items.length > 1 && i < items.length - 1) {
                buffer.append("
");
              }
            }
            dragDataText = buffer.toString();
          }
          break;
        }
        case TEXT: {
          Text text = (Text) dragControl;
          String s = text.getSelectionText();
          if (s.length() == 0) {
            event.doit = false;
          } else {
            dragDataText = s;
          }
          break;
        }
        case TREE: {
          Tree tree = (Tree) dragControl;
          TreeItem[] items = tree.getSelection();
          if (items.length == 0) {
            event.doit = false;
          } else {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < items.length; i++) {
              buffer.append(items[i].getText());
              if (items.length > 1 && i < items.length - 1) {
                buffer.append("
");
              }
            }
            dragDataText = buffer.toString();
          }
          break;
        }
        case CANVAS: {
          String[] strings = (String[]) dragControl
              .getData("STRINGS");
          if (strings == null || strings.length == 0) {
            event.doit = false;
          } else {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < strings.length; i++) {
              buffer.append(strings[i]);
              if (strings.length > 1 && i < strings.length - 1) {
                buffer.append("
");
              }
            }
            dragDataText = buffer.toString();
          }
          break;
        }
        case LABEL: {
          Label label = (Label) dragControl;
          String string = label.getText();
          if (string.length() == 0) {
            event.doit = false;
          } else {
            dragDataText = string;
          }
          break;
        }
        case LIST: {
          List list = (List) dragControl;
          String[] selection = list.getSelection();
          if (selection.length == 0) {
            event.doit = false;
          } else {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < selection.length; i++) {
              buffer.append(selection[i]);
              if (selection.length > 1
                  && i < selection.length - 1) {
                buffer.append("
");
              }
            }
            dragDataText = buffer.toString();
          }
          break;
        }
        default:
          throw new SWTError(SWT.ERROR_NOT_IMPLEMENTED);
        }
        if (dragDataText != null) {
          dragDataRTF = "{\rtf1{\colortbl;\red255\green0\blue0;}\cf1\b "
              + dragDataText + "}";
          dragDataHTML = "<b>" + dragDataText + "</b>";
        }

        for (int i = 0; i < dragTypes.length; i++) {
          if (dragTypes[i] instanceof TextTransfer
              && dragDataText == null) {
            event.doit = false;
          }
          if (dragTypes[i] instanceof RTFTransfer
              && dragDataRTF == null) {
            event.doit = false;
          }
          if (dragTypes[i] instanceof HTMLTransfer
              && dragDataHTML == null) {
            event.doit = false;
          }
          if (dragTypes[i] instanceof FileTransfer
              && (dragDataFiles == null || dragDataFiles.length == 0)) {
            event.doit = false;
          }
        }
      }
    });
  }

  private void createDragTypes(Composite parent) {
    parent.setLayout(new GridLayout());
    Button b = new Button(parent, SWT.CHECK);
    b.setText("Text Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDragTransfer(TextTransfer.getInstance());
        } else {
          removeDragTransfer(TextTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("RTF Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDragTransfer(RTFTransfer.getInstance());
        } else {
          removeDragTransfer(RTFTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("HTML Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDragTransfer(HTMLTransfer.getInstance());
        } else {
          removeDragTransfer(HTMLTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("File Transfer");
    b.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING));
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDragTransfer(FileTransfer.getInstance());
        } else {
          removeDragTransfer(FileTransfer.getInstance());
        }
      }
    });
    b = new Button(parent, SWT.PUSH);
    b.setText("Select File(s)");
    b.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING));
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        FileDialog dialog = new FileDialog(fileList.getShell(),
            SWT.OPEN | SWT.MULTI);
        String result = dialog.open();
        if (result != null && result.length() > 0) {
          fileList.removeAll();
          String separator = System.getProperty("file.separator");
          String path = dialog.getFilterPath();
          String[] names = dialog.getFileNames();
          for (int i = 0; i < names.length; i++) {
            fileList.add(path + separator + names[i]);
          }
        }
      }
    });
    fileList = new List(parent, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
    GridData data = new GridData();
    data.grabExcessHorizontalSpace = true;
    data.horizontalAlignment = GridData.FILL;
    data.verticalAlignment = GridData.BEGINNING;
    fileList.setLayoutData(data);
  }

  private void createDragWidget(Composite parent) {
    parent.setLayout(new FormLayout());
    Combo combo = new Combo(parent, SWT.READ_ONLY);
    combo.setItems(new String[] { "Toggle Button", "Radio Button",
        "Checkbox", "Canvas", "Label", "List", "Table", "Tree" });
    combo.select(LABEL);
    dragControlType = combo.getSelectionIndex();
    dragControl = createWidget(dragControlType, parent, "Drag Source");

    combo.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Object data = dragControl.getLayoutData();
        Composite parent = dragControl.getParent();
        dragControl.dispose();
        Combo c = (Combo) e.widget;
        dragControlType = c.getSelectionIndex();
        dragControl = createWidget(dragControlType, parent,
            "Drag Source");
        dragControl.setLayoutData(data);
        if (dragEnabled)
          createDragSource();
        parent.layout();
      }
    });

    Button b = new Button(parent, SWT.CHECK);
    b.setText("DragSource");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        dragEnabled = b.getSelection();
        if (dragEnabled) {
          createDragSource();
        } else {
          if (dragSource != null) {
            dragSource.dispose();
          }
          dragSource = null;
        }
      }
    });

    FormData data = new FormData();
    data.top = new FormAttachment(0, 10);
    data.bottom = new FormAttachment(combo, -10);
    data.left = new FormAttachment(0, 10);
    data.right = new FormAttachment(100, -10);
    dragControl.setLayoutData(data);

    data = new FormData();
    data.bottom = new FormAttachment(100, -10);
    data.left = new FormAttachment(0, 10);
    combo.setLayoutData(data);

    data = new FormData();
    data.bottom = new FormAttachment(100, -10);
    data.left = new FormAttachment(combo, 10);
    b.setLayoutData(data);
  }

  private void createDropOperations(Composite parent) {
    parent.setLayout(new RowLayout(SWT.VERTICAL));
    final Button moveButton = new Button(parent, SWT.CHECK);
    moveButton.setText("DND.DROP_MOVE");
    moveButton.setSelection(true);
    dropOperation = DND.DROP_MOVE;
    moveButton.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropOperation |= DND.DROP_MOVE;
        } else {
          dropOperation = dropOperation & ~DND.DROP_MOVE;
          if (dropOperation == 0
              || (dropDefaultOperation & DND.DROP_MOVE) != 0) {
            dropOperation |= DND.DROP_MOVE;
            moveButton.setSelection(true);
          }
        }
        if (dropEnabled) {
          createDropTarget();
        }
      }
    });

    final Button copyButton = new Button(parent, SWT.CHECK);
    copyButton.setText("DND.DROP_COPY");
    copyButton.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropOperation |= DND.DROP_COPY;
        } else {
          dropOperation = dropOperation & ~DND.DROP_COPY;
          if (dropOperation == 0
              || (dropDefaultOperation & DND.DROP_COPY) != 0) {
            dropOperation = DND.DROP_COPY;
            copyButton.setSelection(true);
          }
        }
        if (dropEnabled) {
          createDropTarget();
        }
      }
    });

    final Button linkButton = new Button(parent, SWT.CHECK);
    linkButton.setText("DND.DROP_LINK");
    linkButton.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropOperation |= DND.DROP_LINK;
        } else {
          dropOperation = dropOperation & ~DND.DROP_LINK;
          if (dropOperation == 0
              || (dropDefaultOperation & DND.DROP_LINK) != 0) {
            dropOperation = DND.DROP_LINK;
            linkButton.setSelection(true);
          }
        }
        if (dropEnabled) {
          createDropTarget();
        }
      }
    });

    Button b = new Button(parent, SWT.CHECK);
    b.setText("DND.DROP_DEFAULT");
    defaultParent = new Composite(parent, SWT.NONE);
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropOperation |= DND.DROP_DEFAULT;
          defaultParent.setVisible(true);
        } else {
          dropOperation = dropOperation & ~DND.DROP_DEFAULT;
          defaultParent.setVisible(false);
        }
        if (dropEnabled) {
          createDropTarget();
        }
      }
    });

    defaultParent.setVisible(false);
    GridLayout layout = new GridLayout();
    layout.marginWidth = 20;
    defaultParent.setLayout(layout);
    Label label = new Label(defaultParent, SWT.NONE);
    label.setText("Value for default operation is:");
    b = new Button(defaultParent, SWT.RADIO);
    b.setText("DND.DROP_MOVE");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropDefaultOperation = DND.DROP_MOVE;
          dropOperation |= DND.DROP_MOVE;
          moveButton.setSelection(true);
          if (dropEnabled) {
            createDropTarget();
          }
        }
      }
    });

    b = new Button(defaultParent, SWT.RADIO);
    b.setText("DND.DROP_COPY");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropDefaultOperation = DND.DROP_COPY;
          dropOperation |= DND.DROP_COPY;
          copyButton.setSelection(true);
          if (dropEnabled) {
            createDropTarget();
          }
        }
      }
    });

    b = new Button(defaultParent, SWT.RADIO);
    b.setText("DND.DROP_LINK");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropDefaultOperation = DND.DROP_LINK;
          dropOperation |= DND.DROP_LINK;
          linkButton.setSelection(true);
          if (dropEnabled) {
            createDropTarget();
          }
        }
      }
    });

    b = new Button(defaultParent, SWT.RADIO);
    b.setText("DND.DROP_NONE");
    b.setSelection(true);
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropDefaultOperation = DND.DROP_NONE;
          dropOperation &= ~DND.DROP_DEFAULT;
          if (dropEnabled) {
            createDropTarget();
          }
        }
      }
    });
  }

  private void createDropTarget() {
    if (dropTarget != null)
      dropTarget.dispose();
    dropTarget = new DropTarget(dropControl, dropOperation);
    dropTarget.setTransfer(dropTypes);
    dropTarget.addDropListener(new DropTargetListener() {
      public void dragEnter(DropTargetEvent event) {
        dropConsole.append(">>dragEnter
");
        printEvent(event);
        if (event.detail == DND.DROP_DEFAULT) {
          event.detail = dropDefaultOperation;
        }
        event.feedback = dropFeedback;
      }

      public void dragLeave(DropTargetEvent event) {
        dropConsole.append(">>dragLeave
");
        printEvent(event);
      }

      public void dragOperationChanged(DropTargetEvent event) {
        dropConsole.append(">>dragOperationChanged
");
        printEvent(event);
        if (event.detail == DND.DROP_DEFAULT) {
          event.detail = dropDefaultOperation;
        }
        event.feedback = dropFeedback;
      }

      public void dragOver(DropTargetEvent event) {
        dropConsole.append(">>dragOver
");
        printEvent(event);
        event.feedback = dropFeedback;
      }

      public void drop(DropTargetEvent event) {
        dropConsole.append(">>drop
");
        printEvent(event);
        String[] strings = null;
        if (TextTransfer.getInstance().isSupportedType(
            event.currentDataType)
            || RTFTransfer.getInstance().isSupportedType(
                event.currentDataType)
            || HTMLTransfer.getInstance().isSupportedType(
                event.currentDataType)) {
          strings = new String[] { (String) event.data };
        }
        if (FileTransfer.getInstance().isSupportedType(
            event.currentDataType)) {
          strings = (String[]) event.data;
        }
        if (strings == null || strings.length == 0) {
          dropConsole.append("!!Invalid data dropped");
          return;
        }

        if (strings.length == 1
            && (dropControlType == TABLE || dropControlType == TREE || dropControlType == LIST)) {
          // convert string separated by "
" into an array of strings
          String string = strings[0];
          int count = 0;
          int offset = string.indexOf("
", 0);
          while (offset > 0) {
            count++;
            offset = string.indexOf("
", offset + 1);
          }
          if (count > 0) {
            strings = new String[count + 1];
            int start = 0;
            int end = string.indexOf("
");
            int index = 0;
            while (start < end) {
              strings[index++] = string.substring(start, end);
              start = end + 1;
              end = string.indexOf("
", start);
              if (end == -1)
                end = string.length();
            }
          }
        }
        switch (dropControlType) {
        case BUTTON_CHECK:
        case BUTTON_TOGGLE:
        case BUTTON_RADIO: {
          Button b = (Button) dropControl;
          b.setText(strings[0]);
          break;
        }
        case TABLE: {
          Table table = (Table) dropControl;
          Point p = event.display.map(null, table, event.x, event.y);
          TableItem dropItem = table.getItem(p);
          int index = dropItem == null ? table.getItemCount() : table
              .indexOf(dropItem);
          for (int i = 0; i < strings.length; i++) {
            TableItem item = new TableItem(table, SWT.NONE, index);
            item.setText(0, strings[i]);
            item.setText(1, "dropped item");
          }
          TableColumn[] columns = table.getColumns();
          for (int i = 0; i < columns.length; i++) {
            columns[i].pack();
          }
          break;
        }
        case TEXT: {
          Text text = (Text) dropControl;
          for (int i = 0; i < strings.length; i++) {
            text.append(strings[i] + "
");
          }
          break;
        }
        case TREE: {
          Tree tree = (Tree) dropControl;
          Point p = event.display.map(null, tree, event.x, event.y);
          TreeItem parentItem = tree.getItem(p);
          for (int i = 0; i < strings.length; i++) {
            TreeItem item = parentItem != null ? new TreeItem(
                parentItem, SWT.NONE) : new TreeItem(tree,
                SWT.NONE);
            item.setText(strings[i]);
          }
          break;
        }
        case CANVAS: {
          dropControl.setData("STRINGS", strings);
          dropControl.redraw();
          break;
        }
        case LABEL: {
          Label label = (Label) dropControl;
          label.setText(strings[0]);
          break;
        }
        case LIST: {
          List list = (List) dropControl;
          for (int i = 0; i < strings.length; i++) {
            list.add(strings[i]);
          }
          break;
        }
        default:
          throw new SWTError(SWT.ERROR_NOT_IMPLEMENTED);
        }
      }

      public void dropAccept(DropTargetEvent event) {
        dropConsole.append(">>dropAccept
");
        printEvent(event);
      }
    });
  }

  private void createFeedbackTypes(Group parent) {
    parent.setLayout(new RowLayout(SWT.VERTICAL));
    Button b = new Button(parent, SWT.CHECK);
    b.setText("FEEDBACK_SELECT");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropFeedback |= DND.FEEDBACK_SELECT;
        } else {
          dropFeedback &= ~DND.FEEDBACK_SELECT;
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("FEEDBACK_SCROLL");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropFeedback |= DND.FEEDBACK_SCROLL;
        } else {
          dropFeedback &= ~DND.FEEDBACK_SCROLL;
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("FEEDBACK_INSERT_BEFORE");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropFeedback |= DND.FEEDBACK_INSERT_BEFORE;
        } else {
          dropFeedback &= ~DND.FEEDBACK_INSERT_BEFORE;
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("FEEDBACK_INSERT_AFTER");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropFeedback |= DND.FEEDBACK_INSERT_AFTER;
        } else {
          dropFeedback &= ~DND.FEEDBACK_INSERT_AFTER;
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("FEEDBACK_EXPAND");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          dropFeedback |= DND.FEEDBACK_EXPAND;
        } else {
          dropFeedback &= ~DND.FEEDBACK_EXPAND;
        }
      }
    });
  }

  private void createDropTypes(Composite parent) {
    parent.setLayout(new RowLayout(SWT.VERTICAL));
    Button b = new Button(parent, SWT.CHECK);
    b.setText("Text Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDropTransfer(TextTransfer.getInstance());
        } else {
          removeDropTransfer(TextTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("RTF Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDropTransfer(RTFTransfer.getInstance());
        } else {
          removeDropTransfer(RTFTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("HTML Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDropTransfer(HTMLTransfer.getInstance());
        } else {
          removeDropTransfer(HTMLTransfer.getInstance());
        }
      }
    });

    b = new Button(parent, SWT.CHECK);
    b.setText("File Transfer");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        if (b.getSelection()) {
          addDropTransfer(FileTransfer.getInstance());
        } else {
          removeDropTransfer(FileTransfer.getInstance());
        }
      }
    });
  }

  private void createDropWidget(Composite parent) {
    parent.setLayout(new FormLayout());
    Combo combo = new Combo(parent, SWT.READ_ONLY);
    combo
        .setItems(new String[] { "Toggle Button", "Radio Button",
            "Checkbox", "Canvas", "Label", "List", "Table", "Tree",
            "Text" });
    combo.select(LABEL);
    dropControlType = combo.getSelectionIndex();
    dropControl = createWidget(dropControlType, parent, "Drop Target");
    combo.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Object data = dropControl.getLayoutData();
        Composite parent = dropControl.getParent();
        dropControl.dispose();
        Combo c = (Combo) e.widget;
        dropControlType = c.getSelectionIndex();
        dropControl = createWidget(dropControlType, parent,
            "Drop Target");
        dropControl.setLayoutData(data);
        if (dropEnabled)
          createDropTarget();
        parent.layout();
      }
    });

    Button b = new Button(parent, SWT.CHECK);
    b.setText("DropTarget");
    b.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        Button b = (Button) e.widget;
        dropEnabled = b.getSelection();
        if (dropEnabled) {
          createDropTarget();
        } else {
          if (dropTarget != null) {
            dropTarget.dispose();
          }
          dropTarget = null;
        }
      }
    });

    FormData data = new FormData();
    data.top = new FormAttachment(0, 10);
    data.bottom = new FormAttachment(combo, -10);
    data.left = new FormAttachment(0, 10);
    data.right = new FormAttachment(100, -10);
    dropControl.setLayoutData(data);

    data = new FormData();
    data.bottom = new FormAttachment(100, -10);
    data.left = new FormAttachment(0, 10);
    combo.setLayoutData(data);

    data = new FormData();
    data.bottom = new FormAttachment(100, -10);
    data.left = new FormAttachment(combo, 10);
    b.setLayoutData(data);
  }

  private Control createWidget(int type, Composite parent, String prefix) {
    switch (type) {
    case BUTTON_CHECK: {
      Button button = new Button(parent, SWT.CHECK);
      button.setText(prefix + " Check box");
      return button;
    }
    case BUTTON_TOGGLE: {
      Button button = new Button(parent, SWT.TOGGLE);
      button.setText(prefix + " Toggle button");
      return button;
    }
    case BUTTON_RADIO: {
      Button button = new Button(parent, SWT.RADIO);
      button.setText(prefix + " Radio button");
      return button;
    }
    case TABLE: {
      Table table = new Table(parent, SWT.BORDER | SWT.MULTI);
      TableColumn column1 = new TableColumn(table, SWT.NONE);
      TableColumn column2 = new TableColumn(table, SWT.NONE);
      for (int i = 0; i < 10; i++) {
        TableItem item = new TableItem(table, SWT.NONE);
        item.setText(0, prefix + " name " + i);
        item.setText(1, prefix + " value " + i);
      }
      column1.pack();
      column2.pack();
      return table;
    }
    case TEXT: {
      Text text = new Text(parent, SWT.BORDER | SWT.MULTI | SWT.V_SCROLL
          | SWT.H_SCROLL);
      text.setText(prefix + " Text");
      return text;
    }
    case TREE: {
      Tree tree = new Tree(parent, SWT.BORDER);
      for (int i = 0; i < 3; i++) {
        TreeItem item = new TreeItem(tree, SWT.NONE);
        item.setText(prefix + " item " + i);
        for (int j = 0; j < 3; j++) {
          TreeItem subItem = new TreeItem(item, SWT.NONE);
          subItem.setText(prefix + " item " + j);
          for (int k = 0; k < 3; k++) {
            TreeItem subsubItem = new TreeItem(subItem, SWT.NONE);
            subsubItem.setText(prefix + " item " + k);
          }
        }
      }
      return tree;
    }
    case CANVAS: {
      Canvas canvas = new Canvas(parent, SWT.BORDER);
      canvas.setData("STRINGS",
          new String[] { prefix + " Canvas widget" });
      canvas.addPaintListener(new PaintListener() {
        public void paintControl(PaintEvent e) {
          Canvas c = (Canvas) e.widget;
          Image image = (Image) c.getData("IMAGE");
          if (image != null) {
            e.gc.drawImage(image, 5, 5);
          } else {
            String[] strings = (String[]) c.getData("STRINGS");
            if (strings != null) {
              FontMetrics metrics = e.gc.getFontMetrics();
              int height = metrics.getHeight();
              int y = 5;
              for (int i = 0; i < strings.length; i++) {
                e.gc.drawString(strings[i], 5, y);
                y += height + 5;
              }
            }
          }
        }
      });
      return canvas;
    }
    case LABEL: {
      Label label = new Label(parent, SWT.BORDER);
      label.setText(prefix + " Label");
      return label;
    }
    case LIST: {
      List list = new List(parent, SWT.BORDER);
      list
          .setItems(new String[] { prefix + " Item a",
              prefix + " Item b", prefix + " Item c",
              prefix + " Item d" });
      return list;
    }
    default:
      throw new SWTError(SWT.ERROR_NOT_IMPLEMENTED);
    }
  }

  public void open(Display display) {
    Shell shell = new Shell(display);
    shell.setText("Drag and Drop Example");
    shell.setLayout(new FillLayout());

    ScrolledComposite sc = new ScrolledComposite(shell, SWT.H_SCROLL
        | SWT.V_SCROLL);
    Composite parent = new Composite(sc, SWT.NONE);
    sc.setContent(parent);
    parent.setLayout(new FormLayout());

    Label dragLabel = new Label(parent, SWT.LEFT);
    dragLabel.setText("Drag Source:");

    Group dragWidgetGroup = new Group(parent, SWT.NONE);
    dragWidgetGroup.setText("Widget");
    createDragWidget(dragWidgetGroup);

    Composite cLeft = new Composite(parent, SWT.NONE);
    cLeft.setLayout(new GridLayout(2, false));

    Group dragOperationsGroup = new Group(cLeft, SWT.NONE);
    dragOperationsGroup.setLayoutData(new GridData(SWT.LEFT, SWT.FILL,
        false, false, 1, 1));
    dragOperationsGroup.setText("Allowed Operation(s):");
    createDragOperations(dragOperationsGroup);

    Group dragTypesGroup = new Group(cLeft, SWT.NONE);
    dragTypesGroup.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true,
        false, 1, 1));
    dragTypesGroup.setText("Transfer Type(s):");
    createDragTypes(dragTypesGroup);

    dragConsole = new Text(cLeft, SWT.READ_ONLY | SWT.BORDER | SWT.V_SCROLL
        | SWT.H_SCROLL | SWT.MULTI);
    dragConsole.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true,
        2, 1));
    Menu menu = new Menu(shell, SWT.POP_UP);
    MenuItem item = new MenuItem(menu, SWT.PUSH);
    item.setText("Clear");
    item.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {
        dragConsole.setText("");
      }
    });
    item = new MenuItem(menu, SWT.CHECK);
    item.setText("Show Event detail");
    item.addSelectionListener(new SelectionAdapter() {