Google Maps KML Importing Utility

1. Introduction
2. Add a KML layer
3. Clear a KML layer
4. Access KML containers
5. Access KML placemarks and KML ground overlays
6. Access KML properties
7. KML supported features

Introduction

KML is an extension of the XML data format and represents geographical data on a map. Using this utility, you can convert KML objects into geographical shapes and render them as a layer on top of a map. To add and remove your KML data to and from the map, call addLayerToMap() and removeLayerFromMap() respectively. To access properties in a KML object, call getProperties() on any Placemark, GroundOverlay, Document or Folder.

Add a KML layer to the map

To add a data layer to the map, first create an instance of the KmlLayer class. There are two ways to instantiate a KmlLayer .

To import and render a KML dataset from a local resource, you need:

• A GoogleMap object where the layer is to be rendered.
• A local resource file containing the KML data.
• A Context object, which is required to open a local resource file.

 val 
  
 layer 
  
 = 
  
 KmlLayer 
 ( 
 map 
 , 
  
 R 
 . 
 raw 
 . 
 geojson_file 
 , 
  
 context 
 ) 
  

 KmlLayer 
  
 layer 
  
 = 
  
 new 
  
 KmlLayer 
 ( 
 map 
 , 
  
 R 
 . 
 raw 
 . 
 geojson_file 
 , 
  
 context 
 ); 
  

To import and render a KML dataset from a local stream, you need:

• A GoogleMap object where the layer is to be rendered.
• An InputStream containing the KML data.
• A Context object, which is required to open local resources.

 val 
  
 inputStream 
 : 
  
 InputStream? 
 = 
  
 // InputStream containing KML data 
 val 
  
 layer 
  
 = 
  
 KmlLayer 
 ( 
 map 
 , 
  
 inputStream 
 , 
  
 context 
 ) 
  

 InputStream 
  
 inputStream 
  
 = 
  
 // InputStream containing KML data 
 KmlLayer 
  
 layer 
  
 = 
  
 new 
  
 KmlLayer 
 ( 
 map 
 , 
  
 inputStream 
 , 
  
 context 
 ); 
  

After you have created a KmlLayer , call addLayerToMap()() to add the imported data onto the map.

 layer 
 . 
 addLayerToMap 
 () 
  

 layer 
 . 
 addLayerToMap 
 (); 
  

Clear a KML layer

Let's assume that you have created this KmlLayer :

 val 
  
 inputStream 
 : 
  
 InputStream? 
 = 
  
 // InputStream containing KML data 
 val 
  
 layer 
  
 = 
  
 KmlLayer 
 ( 
 map 
 , 
  
 inputStream 
 , 
  
 context 
 ) 
  

 InputStream 
  
 inputStream 
  
 = 
  
 // InputStream containing KML data 
 KmlLayer 
  
 layer 
  
 = 
  
 new 
  
 KmlLayer 
 ( 
 map 
 , 
  
 inputStream 
 , 
  
 context 
 ); 
  

To remove the layer from the map, call removeLayerFromMap() :

 layer 
 . 
 removeLayerFromMap 
 () 
  

 layer 
 . 
 removeLayerFromMap 
 (); 
  

Access KML containers

To access any containers that have been added to your layer, you can call getContainers() on the layer that you have created. To check if any container has nested containers, you can call hasContainers() . To access these nested containers, similar to what you are able to do in your layer, you can call getContainers()

To access containers which are not nested in a KmlLayer or KmlContainer:

 for 
  
 ( 
 containers 
  
 in 
  
 layer 
 . 
 containers 
 ) 
  
 { 
  
 // Do something to container 
 } 
  

 for 
  
 ( 
 KmlContainer 
  
 containers 
  
 : 
  
 layer 
 . 
 getContainers 
 ()) 
  
 { 
  
 // Do something to container 
 } 
  

To access containers which are nested in a KmlLayer or KmlContainer :

 fun 
  
 accessContainers 
 ( 
 containers 
 : 
  
 Iterable<KmlContainer> 
 ) 
  
 { 
  
 for 
  
 ( 
 container 
  
 in 
  
 containers 
 ) 
  
 { 
  
 if 
  
 ( 
 container 
 . 
 hasContainers 
 ()) 
  
 { 
  
 accessContainers 
 ( 
 container 
 . 
 containers 
 ) 
  
 } 
  
 } 
  

 public 
  
 void 
  
 accessContainers 
 ( 
 Iterable<KmlContainer> 
  
 containers 
 ) 
  
 { 
  
 for 
  
 ( 
 KmlContainer 
  
 container 
  
 : 
  
 containers 
 ) 
  
 { 
  
 if 
  
 ( 
 container 
 . 
 hasContainers 
 ()) 
  
 { 
  
 accessContainers 
 ( 
 container 
 . 
 getContainers 
 ()); 
  
 } 
  
 } 
 } 
  

Access KML placemarks and KML ground overlays

To access any placemark or ground overlay that has been added to the layer, you can call getPlacemarks() or getGroundOverlays() on a layer or container. Calling either will return an iterable of KmlPlacemarks or KmlGroundOverlays respectively.

For example, to access a KmlPlacemark objects from a layer:

 for 
  
 ( 
 placemark 
  
 in 
  
 layer 
 . 
 placemarks 
 ) 
  
 { 
  
 // Do something to Placemark 
 } 
  

 for 
  
 ( 
 KmlPlacemark 
  
 placemark 
  
 : 
  
 layer 
 . 
 getPlacemarks 
 ()) 
  
 { 
  
 // Do something to Placemark 
 } 
  

Access KML properties

To access any property in a container or placemark, call getProperty() and give it a property key. You can also call hasProperty() to check if it exists. This sample shows how to retrieve the property value "name" from a container, if it exists.

 for 
  
 ( 
 container 
  
 in 
  
 layer 
 . 
 containers 
 ) 
  
 { 
  
 if 
  
 ( 
 container 
 . 
 hasProperty 
 ( 
 "name" 
 )) 
  
 { 
  
 Log 
 . 
 i 
 ( 
 "KML" 
 , 
  
 container 
 . 
 getProperty 
 ( 
 "name" 
 )) 
  
 } 
 } 
  

 for 
  
 ( 
 KmlContainer 
  
 container 
  
 : 
  
 layer 
 . 
 getContainers 
 ()) 
  
 { 
  
 if 
  
 ( 
 container 
 . 
 hasProperty 
 ( 
 "name" 
 )) 
  
 { 
  
 Log 
 . 
 i 
 ( 
 "KML" 
 , 
  
 container 
 . 
 getProperty 
 ( 
 "name" 
 )); 
  
 } 
 } 
  

KML Geometry Click Events

You can use KmlLayer.OnFeatureClickListener() to listen for click events on the geometry features on the map. The following example logs the ID of a feature when the user clicks the feature:

 // Set a listener for geometry clicked events. 
 layer 
 . 
 setOnFeatureClickListener 
  
 { 
  
 feature 
  
 - 
>  
 Log 
 . 
 i 
 ( 
  
 "KML" 
 , 
  
 "Feature clicked: " 
  
 + 
  
 feature 
 . 
 id 
  
 ) 
 } 
  

 // Set a listener for geometry clicked events. 
 layer 
 . 
 setOnFeatureClickListener 
 ( 
 new 
  
 KmlLayer 
 . 
 OnFeatureClickListener 
 () 
  
 { 
  
 @Override 
  
 public 
  
 void 
  
 onFeatureClick 
 ( 
 Feature 
  
 feature 
 ) 
  
 { 
  
 Log 
 . 
 i 
 ( 
 "KML" 
 , 
  
 "Feature clicked: " 
  
 + 
  
 feature 
 . 
 getId 
 ()); 
  
 } 
 }); 
  

See the demo app

For an example of importing a KML file and creating a layer with it, take a look at the KmlDemoActivity in the demo app that ships with the utility library. The setup guide shows you how to run the demo app.

KML supported features