snippet229.java

对于可视的桌面开发系统的一些详细的设计资料

/*******************************************************************************
 * 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;

/* 
 * Table example snippet: Draw a custom gradient selection
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.3
 */

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet229 {
public static void main(String [] args) {
	final Display display = new Display();
	Shell shell = new Shell(display);
	shell.setText("Custom gradient selection for Table");
	shell.setLayout(new FillLayout());
	final Table table = new Table(shell, SWT.MULTI | SWT.FULL_SELECTION);
	table.setHeaderVisible(true);
	table.setLinesVisible(true);
	int columnCount = 3;
	for (int i=0; i<columnCount; i++) {
		TableColumn column = new TableColumn(table, SWT.NONE);
		column.setText("Column " + i);	
	}
	int itemCount = 8;
	for(int i = 0; i < itemCount; i++) {
		TableItem item = new TableItem(table, SWT.NONE);
		item.setText(new String[] {"item "+i+" a", "item "+i+" b", "item "+i+" c"});
	}		
	/*
	 * NOTE: MeasureItem, PaintItem and EraseItem are called repeatedly.
	 * Therefore, it is critical for performance that these methods be
	 * as efficient as possible.
	 */
	table.addListener(SWT.EraseItem, new Listener() {
		public void handleEvent(Event event) {
			event.detail &= ~SWT.HOT;	
			if((event.detail & SWT.SELECTED) != 0) {
				GC gc = event.gc;
				Rectangle area = table.getClientArea();
				/*
				 * If you wish to paint the selection beyond the end of
				 * last column, you must change the clipping region.
				 */
				int columnCount = table.getColumnCount();
				if (event.index == columnCount - 1 || columnCount == 0) {
					int width = area.x + area.width - event.x;
					if (width > 0) {
						Region region = new Region();
						gc.getClipping(region);
						region.add(event.x, event.y, width, event.height); 
						gc.setClipping(region);
						region.dispose();
					}
				}
				gc.setAdvanced(true);
				if (gc.getAdvanced()) gc.setAlpha(127);								
				Rectangle rect = event.getBounds();
				Color foreground = gc.getForeground();
				Color background = gc.getBackground();
				gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
				gc.setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
				gc.fillGradientRectangle(0, rect.y, 500, rect.height, false);
				// restore colors for subsequent drawing
				gc.setForeground(foreground);
				gc.setBackground(background);
				event.detail &= ~SWT.SELECTED;					
			}						
		}
	});		
	for (int i=0; i<columnCount; i++) {
		table.getColumn(i).pack();
	}	
	table.setSelection(table.getItem(0));
	shell.setSize(500, 200);
	shell.open();
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch()) display.sleep();
	}
	display.dispose();	
}
}