Chapter 2: OpenLayers.Map

Here I give a simple demo how to write map class.

1. MapOptions
2. Map

1.  MapOptions

     A JSON object in JavaScript, but in GWT you must write a class extend BaseJavaScriptObject for it. Because it is a simple JSON, so result in the createNew method as following. In this JSON, "resolutions" and "controls" are JavaScript Array, so I must convert Object[] to JavaScript Array then can setProperty.

 

package org.gwtopenmaps.openlayers.client;

import org.gwtopenmaps.openlayers.client.common.BaseJavaScriptObject;
import org.gwtopenmaps.openlayers.client.common.JavaScriptObjectHelper;
import org.gwtopenmaps.openlayers.client.control.Control;

import com.google.gwt.core.client.JavaScriptObject;

public class MapOptions extends BaseJavaScriptObject {

	protected MapOptions() {}
	
	public static MapOptions createNew() {
		return (MapOptions) JavaScriptObject.createObject();
	}
	
	public final void setProjection(String projection) {
		setProperty("projection", projection);
	}
	
	public final void setResolutions(Double... resolutions) {
		JavaScriptObject javaScriptArray = JavaScriptObjectHelper.toJavaScriptArray((Object[]) resolutions);
		setProperty("resolutions", javaScriptArray);
	}
	
	public final void setPanRatio(int panRatio) {
		setProperty("panRatio", panRatio);
	}
	
	public final void setPanDuration(int panDuration) {
		setProperty("panDuration", panDuration);
	}
	
	public final void setControls(Control... controls) {
		JavaScriptObject javaScriptArray = JavaScriptObjectHelper.toJavaScriptArray((Object[]) controls);
		setProperty("controls", javaScriptArray);
	}
}

 

2. Map

     Because this is a small demo, so just see the code following...

 

package org.gwtopenmaps.openlayers.client;

import org.gwtopenmaps.openlayers.client.common.BaseJavaScriptObject;
import org.gwtopenmaps.openlayers.client.control.Control;
import org.gwtopenmaps.openlayers.client.layer.Layer;

public class Map extends BaseJavaScriptObject {

	protected Map() {
	}
	
	public static native Map createNew(String divId, MapOptions mapOptions) /*-{
		return new $wnd.OpenLayers.Map(divId, mapOptions);
	}-*/;
	
	public final void addLayer(Layer layer) {
		invokeMethodReturnJavaScriptObject("addLayer", layer);
	}
	
	public final void setCenter(LonLat lonLat, int zoom) {
		invokeMethodReturnJavaScriptObject("setCenter", lonLat, zoom);
	}
	
	public final Control getControl(String id) {
		return (Control) invokeMethodReturnJavaScriptObject("getControl", id);
	}
	
	public final int getZoom() {
		return invokeMethodReturnInt("getZoom");
	}
}

 

to be continued...