org.eclipse.swt.snippets.Snippet46.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet46.java

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/*******************************************************************************
 * Copyright (c) 2000, 2016 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
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Composite example snippet: intercept mouse events (drag a button with the mouse)
 *
 * 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.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet46 {
    public static void main(String[] args) {
        Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setText("Snippet 46");
        final Composite composite = new Composite(shell, SWT.NONE);
        composite.setEnabled(false);
        composite.setLayout(new FillLayout());
        Button button = new Button(composite, SWT.PUSH);
        button.setText("Button");
        composite.pack();
        composite.setLocation(10, 10);
        final Point[] offset = new Point[1];
        Listener listener = event -> {
            switch (event.type) {
            case SWT.MouseDown:
                Rectangle rect = composite.getBounds();
                if (rect.contains(event.x, event.y)) {
                    Point pt1 = composite.toDisplay(0, 0);
                    Point pt2 = shell.toDisplay(event.x, event.y);
                    offset[0] = new Point(pt2.x - pt1.x, pt2.y - pt1.y);
                }
                break;
            case SWT.MouseMove:
                if (offset[0] != null) {
                    Point pt = offset[0];
                    composite.setLocation(event.x - pt.x, event.y - pt.y);
                }
                break;
            case SWT.MouseUp:
                offset[0] = null;
                break;
            }
        };
        shell.addListener(SWT.MouseDown, listener);
        shell.addListener(SWT.MouseUp, listener);
        shell.addListener(SWT.MouseMove, listener);
        shell.setSize(300, 300);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}