How to draw a path on a map using kml file

Question

Can I parse kml file in order to display paths or points in Android? Please could you help me with that?

This is kml sample code which I would like to display in android google map:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<name>Paths</name>
<description>Examples of paths. Note that the tessellate tag is by default
  set to 0. If you want to create tessellated lines, they must be authored
  (or edited) directly in KML.</description>
<Style id="yellowLineGreenPoly">
  <LineStyle>
    <color>7f00ffff</color>
    <width>4</width>
  </LineStyle>
  <PolyStyle>
    <color>7f00ff00</color>
  </PolyStyle>
</Style>
<Placemark>
  <name>Absolute Extruded</name>
  <description>Transparent green wall with yellow outlines</description>
  <styleUrl>#yellowLineGreenPoly</styleUrl>
  <LineString>
    <extrude>1</extrude>
    <tessellate>1</tessellate>
    <altitudeMode>absolute</altitudeMode>
    <coordinates> -112.2550785337791,36.07954952145647,2357
      -112.2549277039738,36.08117083492122,2357
      -112.2552505069063,36.08260761307279,2357
      -112.2564540158376,36.08395660588506,2357
      -112.2580238976449,36.08511401044813,2357
      -112.2595218489022,36.08584355239394,2357
      -112.2608216347552,36.08612634548589,2357
      -112.262073428656,36.08626019085147,2357
      -112.2633204928495,36.08621519860091,2357
      -112.2644963846444,36.08627897945274,2357
      -112.2656969554589,36.08649599090644,2357 
    </coordinates>
    <LineString>
    </Placemark>
    </Document>
    </kml>

When I'm loading this file to standard web google map it displays it nicely but when I'm trying the same thing with android google map it doesn't do that. It just takes me to some locations and that's it. I was thinking of changing listener class. Currently it looks like that:

private class MyLocationListener implements LocationListener 
{
    @Override
    public void onLocationChanged(Location loc) {
        if (loc != null) {
            latitude = (loc.getLatitude() * 1E6);
            longitude = (loc.getLongitude() * 1E6);
             Toast.makeText(getBaseContext(), 
                     "Location changed : Lat: " + latitude + 
                     " Lng: " + longitude, 
                     Toast.LENGTH_SHORT).show();

             GeoPoint p = new GeoPoint(
                     (int) (loc.getLatitude() * 1E6), 
                     (int) (loc.getLongitude() * 1E6));

             mc.animateTo(p);
             mapView.invalidate();
           }
    }

//---------------------------------------------------------------
    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onStatusChanged(String provider, int status, 
        Bundle extras) {
        //TODO Auto-generated method stub
    }

Please can someone tell me what's I'm doing wrong here?

User · Answer

There is now a beta available of Google Maps KML Importing Utility.

It is part of the Google Maps Android API Utility Library. As documented it allows loading KML files from streams

KmlLayer layer = new KmlLayer(getMap(), kmlInputStream, getApplicationContext());

or local resources

KmlLayer layer = new KmlLayer(getMap(), R.raw.kmlFile, getApplicationContext());

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

layer.addLayerToMap();

User · Answer

Mathias Lin code working beautifully  However  you might want to consider changing this part inside drawPath method    if  lngLat length  gt   2  amp  amp  gp1 getLatitudeE6    gt  0  amp  amp  gp1 getLongitudeE6    gt  0                      amp  amp  gp2 getLatitudeE6    gt  0  amp  amp  gp2 getLongitudeE6    gt  0      GeoPoint can be less than zero as well  I switch mine to        if  lngLat length  gt   2  amp  amp  gp1 getLatitudeE6      0  amp  amp  gp1 getLongitudeE6      0                      amp  amp  gp2 getLatitudeE6      0  amp  amp  gp2 getLongitudeE6      0      Thank you  D

User · Answer

Thank Mathias Lin  tested and it works   In addition  sample implementation of Mathias s method in activity can be as follows   public class DirectionMapActivity extends MapActivity         Override     public void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout directionmap            MapView mapView    MapView  findViewById R id mapview           mapView setBuiltInZoomControls true               Acquire a reference to the system Location Manager         LocationManager locationManager    LocationManager  this getSystemService Context LOCATION SERVICE            String locationProvider   LocationManager NETWORK PROVIDER          Location lastKnownLocation   locationManager getLastKnownLocation locationProvider            StringBuilder urlString   new StringBuilder            urlString append  http   maps google com maps f d amp hl en            urlString append   amp saddr      from         urlString append  Double toString lastKnownLocation getLatitude               urlString append               urlString append  Double toString lastKnownLocation getLongitude               urlString append   amp daddr      to         urlString append  Double toString  double dest 0  1 0E6             urlString append               urlString append  Double toString  double dest 1  1 0E6             urlString append   amp ie UTF8 amp 0 amp om 0 amp output kml             try                 setup the url             URL url   new URL urlString toString                    create the factory             SAXParserFactory factory   SAXParserFactory newInstance                   create a parser             SAXParser parser   factory newSAXParser                   create the reader  scanner              XMLReader xmlreader   parser getXMLReader                   instantiate our handler             NavigationSaxHandler navSaxHandler   new NavigationSaxHandler                   assign our handler             xmlreader setContentHandler navSaxHandler                  get our data via the url class             InputSource is   new InputSource url openStream                    perform the synchronous parse                        xmlreader parse is                  get the results - should be a fully populated RSSFeed instance  or null on error             NavigationDataSet ds   navSaxHandler getParsedData                    draw path             drawPath ds  Color parseColor   add331    mapView                    find boundary by using itemized overlay             GeoPoint destPoint   new GeoPoint dest 0  dest 1                GeoPoint currentPoint   new GeoPoint  new Double lastKnownLocation getLatitude   1E6  intValue                                                    new Double lastKnownLocation getLongitude   1E6  intValue                   Drawable dot   this getResources   getDrawable R drawable pixel               MapItemizedOverlay bgItemizedOverlay   new MapItemizedOverlay dot this               OverlayItem currentPixel   new OverlayItem destPoint  null  null                OverlayItem destPixel   new OverlayItem currentPoint  null  null                bgItemizedOverlay addOverlay currentPixel               bgItemizedOverlay addOverlay destPixel                   center and zoom in the map             MapController mc   mapView getController                mc zoomToSpan bgItemizedOverlay getLatSpanE6   2 bgItemizedOverlay getLonSpanE6   2               mc animateTo new GeoPoint                       currentPoint getLatitudeE6     destPoint getLatitudeE6      2                        currentPoint getLongitudeE6     destPoint getLongitudeE6      2               catch Exception e                Log d  DirectionMap   Exception parsing kml                             and the rest of the methods in activity  e g  drawPath   etc      MapItemizedOverlay java  public class MapItemizedOverlay extends ItemizedOverlay      private ArrayList lt OverlayItem gt  mOverlays   new ArrayList lt OverlayItem gt         private Context mContext       public MapItemizedOverlay Drawable defaultMarker  Context context              super boundCenterBottom defaultMarker              mContext   context             public void addOverlay OverlayItem overlay            mOverlays add overlay           populate                Override     protected OverlayItem createItem int i          return mOverlays get i               Override     public int size           return mOverlays size

User · Answer

In above code  you don t pass the kml data to your mapView anywhere in your code  as far as I can see  To display the route  you should parse the kml data i e  via SAX parser  then display the route markers on the map   See the code below for an example  but it s not complete though - just for you as a reference and get some idea   This is a simple bean I use to hold the route information I will be parsing   package com myapp android model navigation   import java util ArrayList  import java util Iterator    public class NavigationDataSet     private ArrayList lt Placemark gt  placemarks   new ArrayList lt Placemark gt     private Placemark currentPlacemark  private Placemark routePlacemark   public String toString         String s          for  Iterator lt Placemark gt  iter placemarks iterator   iter hasNext               Placemark p    Placemark iter next            s    p getTitle       n    p getDescription       n n             return s     public void addCurrentPlacemark         placemarks add currentPlacemark      public ArrayList lt Placemark gt  getPlacemarks         return placemarks     public void setPlacemarks ArrayList lt Placemark gt  placemarks        this placemarks   placemarks     public Placemark getCurrentPlacemark         return currentPlacemark     public void setCurrentPlacemark Placemark currentPlacemark        this currentPlacemark   currentPlacemark     public Placemark getRoutePlacemark         return routePlacemark     public void setRoutePlacemark Placemark routePlacemark        this routePlacemark   routePlacemark         And the SAX Handler to parse the kml   package com myapp android model navigation   import android util Log  import com myapp android myapp  import org xml sax Attributes  import org xml sax SAXException  import org xml sax helpers DefaultHandler   import com myapp android model navigation NavigationDataSet  import com myapp android model navigation Placemark    public class NavigationSaxHandler extends DefaultHandler                                                                         Fields                                                                     private boolean in kmltag   false    private boolean in placemarktag   false    private boolean in nametag   false   private boolean in descriptiontag   false   private boolean in geometrycollectiontag   false   private boolean in linestringtag   false   private boolean in pointtag   false   private boolean in coordinatestag   false    private StringBuffer buffer    private NavigationDataSet navigationDataSet   new NavigationDataSet                                                                           Getter  amp  Setter                                                                     public NavigationDataSet getParsedData           navigationDataSet getCurrentPlacemark   setCoordinates buffer toString   trim           return this navigationDataSet                                                                             Methods                                                                     Override   public void startDocument   throws SAXException          this navigationDataSet   new NavigationDataSet            Override   public void endDocument   throws SAXException             Nothing to do           Gets be called on opening tags like        lt tag gt       Can provide attribute s   when xml was like        lt tag attribute  attributeValue  gt       Override   public void startElement String namespaceURI  String localName              String qName  Attributes atts  throws SAXException          if  localName equals  kml                  this in kmltag   true          else if  localName equals  Placemark                  this in placemarktag   true              navigationDataSet setCurrentPlacemark new Placemark             else if  localName equals  name                  this in nametag   true          else if  localName equals  description                 this in descriptiontag   true          else if  localName equals  GeometryCollection                 this in geometrycollectiontag   true          else if  localName equals  LineString                 this in linestringtag   true                        else if  localName equals  point                 this in pointtag   true                    else if  localName equals  coordinates                buffer   new StringBuffer              this in coordinatestag   true                                            Gets be called on closing tags like        lt  tag gt        Override   public void endElement String namespaceURI  String localName  String qName              throws SAXException           if  localName equals  kml                 this in kmltag   false            else if  localName equals  Placemark                  this in placemarktag   false          if   Route  equals navigationDataSet getCurrentPlacemark   getTitle                     navigationDataSet setRoutePlacemark navigationDataSet getCurrentPlacemark             else navigationDataSet addCurrentPlacemark              else if  localName equals  name                  this in nametag   false                      else if  localName equals  description                  this in descriptiontag   false           else if  localName equals  GeometryCollection                  this in geometrycollectiontag   false           else if  localName equals  LineString                  this in linestringtag   false                         else if  localName equals  point                  this in pointtag   false                     else if  localName equals  coordinates                  this in coordinatestag   false                     Gets be called on the following structure        lt tag gt characters lt  tag gt        Override  public void characters char ch    int start  int length         if this in nametag            if  navigationDataSet getCurrentPlacemark    null  navigationDataSet setCurrentPlacemark new Placemark             navigationDataSet getCurrentPlacemark   setTitle new String ch  start  length                      else      if this in descriptiontag            if  navigationDataSet getCurrentPlacemark    null  navigationDataSet setCurrentPlacemark new Placemark             navigationDataSet getCurrentPlacemark   setDescription new String ch  start  length                    else     if this in coordinatestag                   if  navigationDataSet getCurrentPlacemark    null  navigationDataSet setCurrentPlacemark new Placemark               navigationDataSet getCurrentPlacemark   setCoordinates new String ch  start  length            buffer append ch  start  length                and a simple placeMark bean   package com myapp android model navigation   public class Placemark    String title  String description  String coordinates  String address   public String getTitle         return title    public void setTitle String title        this title   title    public String getDescription         return description    public void setDescription String description        this description   description    public String getCoordinates         return coordinates    public void setCoordinates String coordinates        this coordinates   coordinates    public String getAddress         return address    public void setAddress String address        this address   address         Finally the service class in my model that calls the calculation   package com myapp android model navigation   import java io IOException  import java io InputStream  import java net URL  import java net URLConnection   import javax xml parsers SAXParser  import javax xml parsers SAXParserFactory   import com myapp android myapp  import org xml sax InputSource  import org xml sax XMLReader   import android util Log   public class MapService    public static final int MODE ANY   0  public static final int MODE CAR   1  public static final int MODE WALKING   2    public static String inputStreamToString  InputStream in  throws IOException       StringBuffer out   new StringBuffer        byte   b   new byte 4096       for  int n   n   in read b      -1             out append new String b  0  n              return out toString        public static NavigationDataSet calculateRoute Double startLat  Double startLng  Double targetLat  Double targetLng  int mode        return calculateRoute startLat         startLng  targetLat         targetLng  mode      public static NavigationDataSet calculateRoute String startCoords  String targetCoords  int mode        String urlPedestrianMode    http   maps google com maps      saddr     startCoords     amp daddr                 targetCoords     amp sll     startCoords     amp dirflg w amp hl en amp ie UTF8 amp z 14 amp output kml        Log d myapp APP   urlPedestrianMode    urlPedestrianMode        String urlCarMode    http   maps google com maps      saddr     startCoords     amp daddr                 targetCoords     amp sll     startCoords     amp hl en amp ie UTF8 amp z 14 amp output kml        Log d myapp APP   urlCarMode    urlCarMode        NavigationDataSet navSet   null         for mode any  try pedestrian route calculation first  if it fails  fall back to car route     if  mode  MODE ANY  mode  MODE WALKING  navSet   MapService getNavigationDataSet urlPedestrianMode       if  mode  MODE ANY amp  amp navSet  null  mode  MODE CAR  navSet   MapService getNavigationDataSet urlCarMode       return navSet            Retrieve navigation data set from either remote URL or String     param url     return navigation set     public static NavigationDataSet getNavigationDataSet String url            urlString    http   192 168 1 100 80 test kml       Log d myapp APP  urlString -- gt  gt      url       NavigationDataSet navigationDataSet   null      try                              final URL aUrl   new URL url           final URLConnection conn   aUrl openConnection            conn setReadTimeout 15   1000       timeout for reading the google maps data  15 secs         conn connect                Get a SAXParser from the SAXPArserFactory             SAXParserFactory spf   SAXParserFactory newInstance             SAXParser sp   spf newSAXParser                 Get the XMLReader of the SAXParser we created             XMLReader xr   sp getXMLReader                Create a new ContentHandler and apply it to the XML-Reader            NavigationSaxHandler navSax2Handler   new NavigationSaxHandler             xr setContentHandler navSax2Handler                Parse the xml-data from our URL              xr parse new InputSource aUrl openStream                  Our NavigationSaxHandler now provides the parsed data to us              navigationDataSet   navSax2Handler getParsedData                 Set the result to be displayed in our GUI              Log d myapp APP  navigationDataSet    navigationDataSet toString            catch  Exception e               Log e myapp APP   error with kml xml   e           navigationDataSet   null                return navigationDataSet         Drawing          Does the actual drawing of the route  based on the geo points provided in the nav set        param navSet     Navigation set bean that holds the route information  incl  geo pos     param color      Color in which to draw the lines     param mMapView01 Map view to draw onto     public void drawPath NavigationDataSet navSet  int color  MapView mMapView01         Log d myapp APP   map color before      color                   color correction for dining  make it darker     if  color    Color parseColor   add331    color   Color parseColor   6C8715        Log d myapp APP   map color after      color        Collection overlaysToAddAgain   new ArrayList        for  Iterator iter   mMapView01 getOverlays   iterator    iter hasNext               Object o   iter next            Log d myapp APP   overlay type      o getClass   getName             if   RouteOverlay class getName   equals o getClass   getName                      mMapView01 getOverlays   remove o               overlaysToAddAgain add o                       mMapView01 getOverlays   clear        mMapView01 getOverlays   addAll overlaysToAddAgain        String path   navSet getRoutePlacemark   getCoordinates        Log d myapp APP   path     path       if  path    null  amp  amp  path trim   length    gt  0            String   pairs   path trim   split                Log d myapp APP   pairs length     pairs length            String   lngLat   pairs 0  split          lngLat 0  longitude lngLat 1  latitude lngLat 2  height          Log d myapp APP   lnglat      lngLat      length      lngLat length            if  lngLat length lt 3  lngLat   pairs 1  split          if first pair is not transferred completely  take seconds pair   TODO           try               GeoPoint startGP   new GeoPoint  int   Double parseDouble lngLat 1     1E6    int   Double parseDouble lngLat 0     1E6                mMapView01 getOverlays   add new RouteOverlay startGP  startGP  1                GeoPoint gp1              GeoPoint gp2   startGP               for  int i   1  i  lt  pairs length  i       the last one would be crash                               lngLat   pairs i  split                        gp1   gp2                   if  lngLat length  gt   2  amp  amp  gp1 getLatitudeE6    gt  0  amp  amp  gp1 getLongitudeE6    gt  0                          amp  amp  gp2 getLatitudeE6    gt  0  amp  amp  gp2 getLongitudeE6    gt  0                            for GeoPoint  first latitude  second longitude                     gp2   new GeoPoint  int   Double parseDouble lngLat 1     1E6    int   Double parseDouble lngLat 0     1E6                         if  gp2 getLatitudeE6      22200000                             mMapView01 getOverlays   add new RouteOverlay gp1  gp2  2  color                            Log d myapp APP   draw     gp1 getLatitudeE6           gp1 getLongitudeE6       TO     gp2 getLatitudeE6           gp2 getLongitudeE6                                                                Log d myapp APP  pair     pairs i                                routeOverlays add new RouteOverlay gp2 gp2  3                mMapView01 getOverlays   add new RouteOverlay gp2  gp2  3              catch  NumberFormatException e                Log e myapp APP   Cannot draw route    e                          mMapView01 getOverlays   addAll routeOverlays      use the default color     mMapView01 setEnabled true       This is the RouteOverlay class   package com myapp android activity map nav   import android graphics Bitmap  import android graphics Canvas  import android graphics Color  import android graphics Paint  import android graphics Point  import android graphics RectF   import com google android maps GeoPoint  import com google android maps MapView  import com google android maps Overlay  import com google android maps Projection   public class RouteOverlay extends Overlay     private GeoPoint gp1  private GeoPoint gp2  private int mRadius 6  private int mode 0  private int defaultColor  private String text     private Bitmap img   null   public RouteOverlay GeoPoint gp1 GeoPoint gp2 int mode       GeoPoint is a int   6E      this gp1   gp1      this gp2   gp2      this mode   mode      defaultColor   999     no defaultColor    public RouteOverlay GeoPoint gp1 GeoPoint gp2 int mode  int defaultColor        this gp1   gp1      this gp2   gp2      this mode   mode      this defaultColor   defaultColor     public void setText String t        this text   t     public void setBitmap Bitmap bitmap         this img   bitmap     public int getMode         return mode      Override public boolean draw  Canvas canvas  MapView mapView  boolean shadow  long when        Projection projection   mapView getProjection        if  shadow    false            Paint paint   new Paint            paint setAntiAlias true           Point point   new Point            projection toPixels gp1  point              mode 1 amp  65306 start         if mode  1                if defaultColor  999              paint setColor Color BLACK      Color BLUE             else             paint setColor defaultColor               RectF oval new RectF point x - mRadius  point y - mRadius              point x   mRadius  point y   mRadius                  start point             canvas drawOval oval  paint                        mode 2 amp  65306 path         else if mode  2                if defaultColor  999              paint setColor Color RED               else             paint setColor defaultColor               Point point2   new Point                projection toPixels gp2  point2               paint setStrokeWidth 5               paint setAlpha defaultColor  Color parseColor   6C8715   220 120               canvas drawLine point x  point y  point2 x point2 y  paint                        mode 3 amp  65306 end            else if mode  3                   the last path                 if defaultColor  999                  paint setColor Color BLACK       Color GREEN             else                 paint setColor defaultColor                Point point2   new Point                projection toPixels gp2  point2               paint setStrokeWidth 5               paint setAlpha defaultColor  Color parseColor   6C8715   220 120               canvas drawLine point x  point y  point2 x point2 y  paint               RectF oval new RectF point2 x - mRadius point2 y - mRadius              point2 x   mRadius point2 y   mRadius                  end point                paint setAlpha 255               canvas drawOval oval  paint                       return super draw canvas  mapView  shadow  when

[android] How to draw a path on a map using kml file?

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