TreeItemLines.java Source code

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Here is the source code for TreeItemLines.java

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/*******************************************************************************
 * 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: Multiple lines in a 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.Point;
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 TreeItemLines {
    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("Multiple lines in a TreeItem");
        shell.setLayout(new FillLayout());
        final 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);
            column.setWidth(100);
        }
        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: {
                    TreeItem item = (TreeItem) event.item;
                    String text = getText(item, event.index);
                    Point size = event.gc.textExtent(text);
                    event.width = size.x;
                    event.height = Math.max(event.height, size.y);
                    break;
                }
                case SWT.PaintItem: {
                    TreeItem item = (TreeItem) event.item;
                    String text = getText(item, event.index);
                    Point size = event.gc.textExtent(text);
                    int offset2 = event.index == 0 ? Math.max(0, (event.height - size.y) / 2) : 0;
                    event.gc.drawText(text, event.x, event.y + offset2, true);
                    break;
                }
                case SWT.EraseItem: {
                    event.detail &= ~SWT.FOREGROUND;
                    break;
                }
                }
            }

            String getText(TreeItem item, int column) {
                String text = item.getText(column);
                if (column != 0) {
                    TreeItem parent = item.getParentItem();
                    int index = parent == null ? tree.indexOf(item) : parent.indexOf(item);
                    if ((index + column) % 3 == 1) {
                        text += "\nnew line";
                    }
                    if ((index + column) % 3 == 2) {
                        text += "\nnew line\nnew line";
                    }
                }
                return text;
            }
        };
        tree.addListener(SWT.MeasureItem, paintListener);
        tree.addListener(SWT.PaintItem, paintListener);
        tree.addListener(SWT.EraseItem, paintListener);

        shell.setSize(600, 400);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}