Java Tutorial/SWT/TreeItem

Add Icon to TreeItem

/*******************************************************************************
 * Copyright (c) 2000, 2006 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
 *******************************************************************************/
//package org.eclipse.swt.snippets;
/* 
 * Tree example snippet: Images on the right side of the TreeItem
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.2
 */
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeColumn;
import org.eclipse.swt.widgets.TreeItem;
public class TreeIconAddItem {
  public static void main(String[] args) {
    Display display = new Display();
    final Image image = display.getSystemImage(SWT.ICON_INFORMATION);
    Shell shell = new Shell(display);
    shell.setText("Images on the right side of the TreeItem");
    shell.setLayout(new FillLayout());
    Tree tree = new Tree(shell, SWT.MULTI | SWT.FULL_SELECTION);
    tree.setHeaderVisible(true);
    tree.setLinesVisible(true);
    int columnCount = 4;
    for (int i = 0; i < columnCount; i++) {
      TreeColumn column = new TreeColumn(tree, SWT.NONE);
      column.setText("Column " + i);
    }
    int itemCount = 3;
    for (int i = 0; i < itemCount; i++) {
      TreeItem item1 = new TreeItem(tree, SWT.NONE);
      item1.setText("item " + i);
      for (int c = 1; c < columnCount; c++) {
        item1.setText(c, "item [" + i + "-" + c + "]");
      }
      for (int j = 0; j < itemCount; j++) {
        TreeItem item2 = new TreeItem(item1, SWT.NONE);
        item2.setText("item [" + i + " " + j + "]");
        for (int c = 1; c < columnCount; c++) {
          item2.setText(c, "item [" + i + " " + j + "-" + c + "]");
        }
        for (int k = 0; k < itemCount; k++) {
          TreeItem item3 = new TreeItem(item2, SWT.NONE);
          item3.setText("item [" + i + " " + j + " " + k + "]");
          for (int c = 1; c < columnCount; c++) {
            item3.setText(c, "item [" + i + " " + j + " " + k + "-" + c + "]");
          }
        }
      }
    }
    /*
     * NOTE: MeasureItem, PaintItem and EraseItem are called repeatedly.
     * Therefore, it is critical for performance that these methods be as
     * efficient as possible.
     */
    Listener paintListener = new Listener() {
      public void handleEvent(Event event) {
        switch (event.type) {
        case SWT.MeasureItem: {
          Rectangle rect = image.getBounds();
          event.width += rect.width;
          event.height = Math.max(event.height, rect.height + 2);
          break;
        }
        case SWT.PaintItem: {
          int x = event.x + event.width;
          Rectangle rect = image.getBounds();
          int offset = Math.max(0, (event.height - rect.height) / 2);
          event.gc.drawImage(image, x, event.y + offset);
          break;
        }
        }
      }
    };
    tree.addListener(SWT.MeasureItem, paintListener);
    tree.addListener(SWT.PaintItem, paintListener);
    for (int i = 0; i < columnCount; i++) {
      tree.getColumn(i).pack();
    }
    shell.setSize(500, 200);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    if (image != null)
      image.dispose();
    display.dispose();
  }
}