org.onecmdb.ui.gwt.toolkit.client.view.dnd.DragControl.java Source code

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Here is the source code for org.onecmdb.ui.gwt.toolkit.client.view.dnd.DragControl.java

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/*
 * OneCMDB, an open source configuration management project.
 * Copyright 2007, Lokomo Systems AB, and individual contributors
 * as indicated by the @authors tag. See the copyright.txt in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.onecmdb.ui.gwt.toolkit.client.view.dnd;

import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.AbsolutePanel;
import com.google.gwt.user.client.ui.MouseListener;
import com.google.gwt.user.client.ui.SourcesMouseEvents;
import com.google.gwt.user.client.ui.Widget;

public class DragControl implements MouseListener {

    private Widget dragWidget;

    public DragControl(Widget dragWidget, SourcesMouseEvents drag) {
        drag.addMouseListener(this);
        this.dragWidget = dragWidget;
    }

    private AbsolutePanel getAbsoluteWidgetPanel(Widget widget) {
        if (widget == null) {
            return (null);
        }
        Widget parent = widget.getParent();
        if (parent == null) {
            return (null);
        }

        if (parent instanceof AbsolutePanel) {
            return ((AbsolutePanel) parent);
        }
        return (getAbsoluteWidgetPanel(parent));
    }

    private int xOffset = 0;
    private int yOffset = 0;
    private boolean dragging = false;

    // Start the drag operation on the component.
    public void onMouseDown(Widget source, int x, int y) {
        if (!dragging) {
            DOM.setCapture(source.getElement());

            dragging = true;

            xOffset = x;
            yOffset = y;

        }
    }

    // Drag the component.
    public void onMouseMove(Widget source, int x, int y) {
        if (dragging) {
            // System.out.println("MOUSE MOVE:" + x + "," + y);

            AbsolutePanel rootPanel = getAbsoluteWidgetPanel(dragWidget);

            int newX = x + dragWidget.getAbsoluteLeft() - xOffset;
            int newY = y + dragWidget.getAbsoluteTop() - yOffset;

            int rootOffsetY = newY - rootPanel.getAbsoluteTop();
            int rootOffsetX = newX - rootPanel.getAbsoluteLeft();
            if (rootOffsetX < 0) {
                rootOffsetX = 0;
            }
            if (rootOffsetY < 0) {
                rootOffsetY = 0;
            }
            rootPanel.setWidgetPosition(dragWidget, rootOffsetX, rootOffsetY);
        }
    }

    // Drop the component.
    public void onMouseUp(Widget source, int x, int y) {
        if (dragging) {

            DOM.releaseCapture(source.getElement());

            dragging = false;

        }
    }

    public void onMouseEnter(Widget sender) {
    }

    public void onMouseLeave(Widget sender) {
    }
}