com.google.gwt.maps.sample.hellomaps.client.KmlOverlayDemo.java Source code

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Here is the source code for com.google.gwt.maps.sample.hellomaps.client.KmlOverlayDemo.java

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/*
 * Copyright 2008 Google Inc.
 * 
 * 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.google.gwt.maps.sample.hellomaps.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.maps.client.MapWidget;
import com.google.gwt.maps.client.control.LargeMapControl;
import com.google.gwt.maps.client.geom.LatLng;
import com.google.gwt.maps.client.overlay.GeoXmlLoadCallback;
import com.google.gwt.maps.client.overlay.GeoXmlOverlay;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.Widget;

/**
 * The Google Maps API supports the KML and GeoRSS data formats for displaying
 * geographic information. These data formats are added to a map using the
 * GGeoXml object, whose factory method takes the URL of a publicly accessible
 * XML file. GGeoXml placemarks are rendered as markers, while GGeoXml polylines
 * and polygons are rendered as Google Maps API polylines and polygons.
 * &ltGroundOverlay> elements within KML files are rendered as GGroundOverlay
 * elements on the map.
 * 
 * GGeoXml objects are added to a map using the addOverlay() method. (You can
 * remove them from the map using removeOverlay().) Both KML and GeoRSS XML
 * files are supported.
 */
public class KmlOverlayDemo extends MapsDemo {

    private static HTML descHTML = null;

    private static final String descString = "<p>Creates a map view of the " + "contents of a KML file</p>"
            + "<p>Displays some paths in a KML file hosted at Google.</p>\n"
            + "<p>Equivalent to the Maps JavaScript API Example: "
            + "<a href=\"http://code.google.com/apis/maps/documentation/examples/geoxml-kml.html\">"
            + "http://code.google.com/apis/maps/documentation/examples/geoxml-kml.html</a></p>\n";

    public static MapsDemoInfo init() {
        return new MapsDemoInfo() {
            @Override
            public MapsDemo createInstance() {
                return new KmlOverlayDemo();
            }

            @Override
            public HTML getDescriptionHTML() {
                if (descHTML == null) {
                    descHTML = new HTML(descString);
                }
                return descHTML;
            }

            @Override
            public String getName() {
                return "KML Overlays";
            }
        };
    }

    private GeoXmlOverlay geoXml = null;
    private boolean geoXmlShown;
    private final MapWidget map;
    private final Button removeAddButton;

    public KmlOverlayDemo() {
        Panel panel = new FlowPanel();
        map = new MapWidget(LatLng.newInstance(41.875696, -87.624207), 11);
        map.setSize("640px", "480px");
        map.addControl(new LargeMapControl());
        panel.add(map);

        // Toggle the visibility of the overlays by
        // adding and removing the overlay.
        removeAddButton = new Button("Remove/Add KML");
        // Toggle the visibility of the overlays
        // using the show() and hide() methods
        final Button showHideButton = new Button("Show/Hide KML");
        removeAddButton.setEnabled(false);
        removeAddButton.addClickListener(new ClickListener() {
            public void onClick(Widget sender) {
                if (geoXml == null) {
                    return;
                }
                if (geoXmlShown) {
                    map.removeOverlay(geoXml);
                    showHideButton.setEnabled(false);
                } else {
                    map.addOverlay(geoXml);
                    showHideButton.setEnabled(true);
                }
                geoXmlShown = !geoXmlShown;
            }
        });
        panel.add(removeAddButton);

        showHideButton.addClickListener(new ClickListener() {
            public void onClick(Widget sender) {
                if (geoXml == null) {
                    return;
                }
                if (geoXml.isHidden()) {
                    geoXml.setVisible(true);
                } else {
                    geoXml.setVisible(false);
                }
            }
        });

        panel.add(showHideButton);
        initWidget(panel);

        GeoXmlOverlay.load("http://mapgadgets.googlepages.com/cta.kml", new GeoXmlLoadCallback() {

            @Override
            public void onFailure(String url, Throwable e) {
                StringBuffer message = new StringBuffer("KML File " + url + " failed to load");
                if (e != null) {
                    message.append(e.toString());
                }
                Window.alert(message.toString());
            }

            @Override
            public void onSuccess(String url, GeoXmlOverlay overlay) {
                geoXml = overlay;
                removeAddButton.setEnabled(true);
                showHideButton.setEnabled(true);
                map.addOverlay(geoXml);
                GWT.log("KML File " + url + "loaded successfully", null);
                GWT.log("Default Center=" + geoXml.getDefaultCenter(), null);
                GWT.log("Default Span=" + geoXml.getDefaultSpan(), null);
                GWT.log("Default Bounds=" + geoXml.getDefaultBounds(), null);
                GWT.log("Supports hide=" + geoXml.supportsHide(), null);
            }
        });
    }

    @Override
    public void onShow() {
        map.clearOverlays();
        if (geoXml != null) {
            map.addOverlay(geoXml);
        }
        geoXmlShown = true;
    }
}