annis.gui.widgets.gwt.client.ui.VGripDragComponent.java Source code

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Here is the source code for annis.gui.widgets.gwt.client.ui.VGripDragComponent.java

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/*
 * Copyright 2012 SFB 632.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package annis.gui.widgets.gwt.client.ui;

import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.event.dom.client.MouseDownEvent;
import com.google.gwt.event.dom.client.MouseDownHandler;
import com.google.gwt.event.dom.client.TouchStartEvent;
import com.google.gwt.event.dom.client.TouchStartHandler;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ApplicationConnection;
import com.vaadin.client.ConnectorMap;
import com.vaadin.client.Paintable;
import com.vaadin.client.Util;
import com.vaadin.client.ui.VCustomComponent;
import com.vaadin.client.ui.dd.VDragAndDropManager;
import com.vaadin.client.ui.dd.VDragEvent;
import com.vaadin.client.ui.dd.VTransferable;

/**
 *
 * @author Thomas Krause <krauseto@hu-berlin.de>
 */
public class VGripDragComponent extends VCustomComponent {

    /** Set the CSS class name to allow styling. */
    public static final String CLASSNAME = "v-moveablepanel";
    public ApplicationConnection client;

    public VGripDragComponent() {
        super();
        addDomHandler(new MouseDownHandler() {
            public void onMouseDown(MouseDownEvent event) {
                if (startDrag(event.getNativeEvent())) {
                    event.preventDefault(); // prevent text selection
                }
            }
        }, MouseDownEvent.getType());

        addDomHandler(new TouchStartHandler() {
            public void onTouchStart(TouchStartEvent event) {
                if (startDrag(event.getNativeEvent())) {
                    /*
                     * Dont let eg. panel start scrolling.
                     */
                    event.stopPropagation();
                }
            }
        }, TouchStartEvent.getType());

        sinkEvents(Event.TOUCHEVENTS);

    }

    private boolean startDrag(NativeEvent event) {
        VTransferable transferable = new VTransferable();
        transferable.setDragSource(ConnectorMap.get(client).getConnector(this));

        Element targetElement = (Element) event.getEventTarget().cast();

        Paintable paintable;
        Widget w = Util.findWidget(targetElement, null);

        if (!w.getStyleName().contains("drag-source-enabled")) {
            return false;
        }

        while (w != null && !(w instanceof Paintable)) {
            w = w.getParent();
        }
        paintable = (Paintable) w;

        transferable.setData("component", paintable);
        VDragEvent dragEvent = VDragAndDropManager.get().startDrag(transferable, event, true);

        transferable.setData("clientX", event.getClientX());
        transferable.setData("clientY", event.getClientY());

        dragEvent.createDragImage(getElement(), true);

        return true;

    }

}