import org.gwtopenmaps.openlayers.client.layer.XYZ; //导入依赖的package包/类
@Override
public Layer getLayer() {				
	XYZOptions layerOptions = new XYZOptions();		
	layerOptions.setSphericalMercator(true);
	
	XYZ xyzLayer = new XYZ(esriLayerName, url, layerOptions);
	xyzLayer.setIsBaseLayer(false);

	return xyzLayer;	
}
 

import org.gwtopenmaps.openlayers.client.layer.XYZ; //导入依赖的package包/类
@Override
protected void init() {
	mapWidget = new MapWidget("100%", "100%", new MapOptions());
	
	// Humanitarian layer
	final OSMOptions hotOption = new OSMOptions();
	hotOption.setIsBaseLayer(true);
	hotOption.crossOriginFix();
	hotOption.setSphericalMercator(true);

	XYZ HOTLayer = new XYZ(I18N.CONSTANTS.humanitarianOSMLayer(), "http://a.tile.openstreetmap.fr/hot/${z}/${x}/${y}.png", hotOption);
			
	// Basic layer
	OSM osmMapnik = new OSM();
	osmMapnik.setName(I18N.CONSTANTS.basicOSMLayer());
	osmMapnik.setIsBaseLayer(true);
	
	// Pin layer
	vectorLayer = new Vector(I18N.CONSTANTS.projectSitesLayer());
	
	// Drag & drop listeners
	dragFeature = createDraggableFeature(vectorLayer);
	
	// Center & zoom
	LonLat lonLat = new LonLat(0, 0);
	lonLat.transform(TRANSFORM_SOURCE, mapWidget.getMap().getProjection());
	
	mapWidget.getMap().addLayer(HOTLayer);
	mapWidget.getMap().addLayer(osmMapnik);
	mapWidget.getMap().addLayer(vectorLayer);
	mapWidget.getMap().addControl(new LayerSwitcher());
	mapWidget.getMap().setCenter(lonLat, 1);
	mapWidget.getMap().updateSize();
	
	getRoot().add(mapWidget);
	setInitialized(true);
}
 

import org.gwtopenmaps.openlayers.client.layer.XYZ; //导入依赖的package包/类
/**
 * <p>initializeMap</p>
 */
private void initializeMap() {
    final MapOptions mo = new MapOptions();
    mo.setProjection(PROJECTION_SPHERICAL_MERCATOR.getProjectionCode());
    mo.setDisplayProjection(PROJECTION_LAT_LON);
    mo.setMaxExtent(new Bounds(-180, -90, 180, 90).transform(PROJECTION_LAT_LON,PROJECTION_SPHERICAL_MERCATOR));
    m_mapWidget = new MapWidget("100%", "100%", mo);
    m_mapHolder.add(m_mapWidget);

    m_map = m_mapWidget.getMap();
    m_map.addControl(new PanZoomBar());
    m_map.addControl(new MousePosition());
    m_map.zoomTo(2);

    initializeImageError();

    XYZOptions xyzOptions = new XYZOptions();
    xyzOptions.setSphericalMercator(true);
    xyzOptions.setAttribution("Default tiles courtesy of <a href=\"http://open.mapquest.co.uk/\">MapQuest</a>");
    XYZ x = new XYZ("OpenStreetMap", getLayerUrl(), xyzOptions);
    x.setIsBaseLayer(true);
    x.setIsVisible(true);
    m_map.addLayer(x);

    m_markersLayer = new Markers("Remote Pollers");
    m_markersLayer.setIsVisible(true);
    m_markersLayer.setIsBaseLayer(false);
    m_map.addLayer(m_markersLayer);

    /*
    final LayerSwitcher switcher = new LayerSwitcher();
    m_map.addControl(switcher);
    */

    m_map.zoomToMaxExtent();

    Window.addResizeHandler(new ResizeHandler() {
        public void onResize(ResizeEvent event) {
            syncMapSizeWithParent();
        }
    });
}