examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet122.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 502845
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Clipboard example snippet: enable/disable menu depending on clipboard content availability
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.0
 */

import static org.eclipse.swt.events.SelectionListener.*;

import org.eclipse.swt.*;
import org.eclipse.swt.dnd.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet122 {

public static void main(String[] args) {
	Display display = new Display();
	final Clipboard cb = new Clipboard(display);
	Shell shell = new Shell(display);
	shell.setText("Snippet 122");
	shell.setLayout(new FillLayout());
	final Text text = new Text(shell, SWT.BORDER | SWT.MULTI | SWT.WRAP);
	Menu menu = new Menu(shell, SWT.POP_UP);
	final MenuItem copyItem = new MenuItem(menu, SWT.PUSH);
	copyItem.setText("Copy");
	copyItem.addSelectionListener(widgetSelectedAdapter(e -> {
			String selection = text.getSelectionText();
			if (selection.length() == 0) {
				return;
			}
			Object[] data = new Object[] { selection };
			Transfer[] types = new Transfer[] { TextTransfer.getInstance() };
			cb.setContents(data, types);
		}));

	final MenuItem pasteItem = new MenuItem(menu, SWT.PUSH);
	pasteItem.setText ("Paste");
	pasteItem.addSelectionListener(widgetSelectedAdapter(e -> {
			String string = (String) (cb.getContents(TextTransfer.getInstance()));
			if (string != null) {
				text.insert(string);
			}
		}));
	menu.addMenuListener(MenuListener.menuShownAdapter(e -> {
		// is copy valid?
		String selection = text.getSelectionText();
		copyItem.setEnabled(selection.length() > 0);
		// is paste valid?
		boolean enabled = false;
		for (TransferData transfer : cb.getAvailableTypes()) {
			if (TextTransfer.getInstance().isSupportedType(transfer)) {
				enabled = true;
				break;
			}
		}
		pasteItem.setEnabled(enabled);
	}));
	text.setMenu (menu);

	shell.setSize(200, 200);
	shell.open();
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch())
			display.sleep();
	}
	cb.dispose();
	display.dispose();
}
}