com.gwt2go.dev.client.ui.widget.LazySimplePanel.java Source code

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Here is the source code for com.gwt2go.dev.client.ui.widget.LazySimplePanel.java

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/*
 * Copyright 2012
 *
 * 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 com.gwt2go.dev.client.ui.widget;

import com.google.gwt.event.dom.client.DragOverEvent;
import com.google.gwt.event.dom.client.DragOverHandler;
import com.google.gwt.event.dom.client.DragStartEvent;
import com.google.gwt.event.dom.client.DragStartHandler;
import com.google.gwt.event.dom.client.DropEvent;
import com.google.gwt.event.dom.client.DropHandler;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.LazyPanel;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

public class LazySimplePanel extends LazyPanel {

    private Element nameSpan;

    public LazySimplePanel(Element nameSpan) {
        this.nameSpan = nameSpan;
    }

    @Override
    protected Widget createWidget() {
        SimplePanel panel = new SimplePanel();
        VerticalPanel vrPanel = new VerticalPanel();

        final Label label = new Label("Drag me");
        label.getElement().setDraggable(Element.DRAGGABLE_TRUE);

        label.addDragStartHandler(new DragStartHandler() {

            @Override
            public void onDragStart(DragStartEvent event) {
                // required
                event.setData("text", "Hello World");

                // optinal: show copy of the image
                event.getDataTransfer().setDragImage(label.getElement(), 10, 10);
            }
        });

        // some widgets do not implement drag handles
        // for that reason you can use addDomHandler()
        /* label.addDomHandler(new DragStartHandler() {
           @Override
           public void onDragStart(DragStartEvent event) {
        // required
        event.setData("text", "Hello World again;)");
            
        // optional
        event.getDataTransfer().setDragImage(label.getElement(), 10, 10);
           }
        }, DragStartEvent.getType()); */

        final Label target = new Label("Drag onto me");
        // required: you must add dragoverhandler to create a target
        target.addDragOverHandler(new DragOverHandler() {
            @Override
            public void onDragOver(DragOverEvent event) {
                target.getElement().getStyle().setBackgroundColor("#ffa");
            }
        });

        // add drop hanlder
        target.addDropHandler(new DropHandler() {
            @Override
            public void onDrop(DropEvent event) {
                // prevent the native text drop
                event.preventDefault();

                // get the data out of the event
                String data = event.getData("text");
                target.setText(data);
            }
        });

        panel.add(vrPanel);
        vrPanel.getElement().appendChild(this.nameSpan);
        vrPanel.add(label);
        vrPanel.add(target);
        return panel;
    }

}