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

Introduction

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

Source

/*
 * 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.maps.client.MapWidget;
import com.google.gwt.maps.client.event.TrafficOverlayChangedHandler;
import com.google.gwt.maps.client.geom.LatLng;
import com.google.gwt.maps.client.overlay.TrafficOverlay;
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.Label;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.Widget;

import java.util.Date;

/**
 * The Google Maps API now allows you to add traffic information to your maps.
 * Traffic information is displayed using the GTrafficOverlay, which implements
 * the GOverlay interface. You add traffic information to your map using the
 * Map.addOverlay() method. GTrafficOverlay has two methods (hide() and show())
 * for toggling display of the traffic overlay. Traffic information is displayed
 * only for supported cities.
 */
public class TrafficOverlayDemo extends MapsDemo {
    private static HTML descHTML = null;

    private static final String descString = "<p>Displays a map centered on Brooklyn, NY USA</p>"
            + "<p>The Google traffic service is called and retrieves an overlay "
            + "representing current traffic conditions.  Pressing the 'Toggle Traffic' "
            + "button will alternately hide and show the overlay.</p>"
            + "<p>Equivalent to the Maps JavaScript API Example: "
            + "<a href=\"http://code.google.com/apis/maps/documentation/examples/trafficOverlay.html\">"
            + "http://code.google.com/apis/maps/documentation/examples/trafficOverlay.html</a></p>\n";

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

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

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

    private MapWidget map;

    private TrafficOverlay trafficInfo;

    private boolean trafficShown;

    public TrafficOverlayDemo() {
        Panel panel = new FlowPanel();

        map = new MapWidget(LatLng.newInstance(40.652513, -73.936615), 12);
        map.setSize("640px", "480px");
        panel.add(map);
        Button toggleTraffic = new Button("Toggle Traffic");
        toggleTraffic.addClickListener(new ClickListener() {
            public void onClick(Widget sender) {
                if (trafficShown) {
                    map.removeOverlay(trafficInfo);
                } else {
                    map.addOverlay(trafficInfo);
                }
                trafficShown = !trafficShown;
            }
        });
        panel.add(toggleTraffic);
        final Label changeLabel = new Label();
        panel.add(changeLabel);
        initWidget(panel);
        trafficInfo = new TrafficOverlay();
        trafficInfo.addTrafficOverlayChangedHandler(new TrafficOverlayChangedHandler() {

            public void onChanged(TrafficOverlayChangedEvent event) {
                changeLabel.setText("Last Changed: " + new Date());
            }

        });
    }

    @Override
    public void onShow() {
        map.clearOverlays();
        map.addOverlay(trafficInfo);
        trafficShown = true;
    }

    // TODO(zundel): Add handler for event "changed"
}