| /******************************************************************************* |
| * Copyright (c) 2000, 2007 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: compute the number of visible rows in a tree |
| * |
| * For a list of all SWT example snippets see |
| * http://www.eclipse.org/swt/snippets/ |
| */ |
| import org.eclipse.swt.*; |
| import org.eclipse.swt.graphics.*; |
| import org.eclipse.swt.widgets.*; |
| import org.eclipse.swt.layout.*; |
| |
| public class Snippet254 { |
| |
| static TreeItem nextItem(Tree tree, TreeItem item) { |
| if (item == null) return null; |
| if (item.getExpanded() && item.getItemCount() > 0) return item.getItem(0); |
| TreeItem childItem = item; |
| TreeItem parentItem = childItem.getParentItem(); |
| int index = parentItem == null ? tree.indexOf(childItem) : parentItem.indexOf(childItem); |
| int count = parentItem == null ? tree.getItemCount() : parentItem.getItemCount(); |
| while (true) { |
| if (index + 1 < count) return parentItem == null ? tree.getItem(index + 1) : parentItem.getItem(index + 1); |
| if (parentItem == null) return null; |
| childItem = parentItem; |
| parentItem = childItem.getParentItem(); |
| index = parentItem == null ? tree.indexOf(childItem) : parentItem.indexOf(childItem); |
| count = parentItem == null ? tree.getItemCount() : parentItem.getItemCount(); |
| } |
| } |
| |
| public static void main(String[] args) { |
| final Display display = new Display(); |
| final Shell shell = new Shell(display); |
| RowLayout layout = new RowLayout (SWT.VERTICAL); |
| layout.fill = true; |
| layout.wrap = false; |
| shell.setLayout (layout); |
| final Tree tree = new Tree (shell, SWT.NONE); |
| for (int i=0; i<32; i++) { |
| TreeItem item0 = new TreeItem (tree, SWT.NONE); |
| item0.setText ("Item " + i + " is quite long"); |
| for (int j=0; j<3; j++) { |
| TreeItem item1 = new TreeItem (item0, SWT.NONE); |
| item1.setText ("Item " + i + " " + j + " is quite long"); |
| for (int k=0; k<3; k++) { |
| TreeItem item2 = new TreeItem (item1, SWT.NONE); |
| item2.setText ("Item " + i + " " + j + " " + k + " is quite long"); |
| for (int l=0; l<3; l++) { |
| TreeItem item3 = new TreeItem (item2, SWT.NONE); |
| item3.setText ("Item " + i + " " + j + " " + k + " " + l + " is quite long"); |
| } |
| } |
| } |
| } |
| tree.setLayoutData(new RowData (200, 200)); |
| final Button button = new Button (shell, SWT.PUSH); |
| button.setText ("Visible Items []"); |
| button.addListener (SWT.Selection, new Listener () { |
| public void handleEvent (Event e) { |
| int visibleCount = 0; |
| Rectangle rect = tree.getClientArea (); |
| TreeItem item = tree.getTopItem (); |
| while (item != null) { |
| visibleCount++; |
| Rectangle itemRect = item.getBounds(); |
| if (itemRect.y + itemRect.height > rect.y + rect.height) { |
| break; |
| } |
| item = nextItem (tree, item); |
| } |
| button.setText ("Visible Items [" + visibleCount + "]"); |
| } |
| }); |
| shell.pack(); |
| shell.open(); |
| while (!shell.isDisposed()) { |
| if (!display.readAndDispatch()) display.sleep(); |
| } |
| display.dispose(); |
| } |
| } |