ソースLatLngと目的地LatLngの間で使用可能なルーティングLatLngの配列を取得するにはどうすればよいですか？

Question

Android Appで利用可能なルートごとに、ソースと目的地の間にGoogleマップにいくつかのチェックポイント（Marker）を追加したいと思っていました。

Answer 1

このGoogleマップのチュートリアルHEREを確認してください。

手順4では、異なるルートを含むJSONを解析します。各ルートから、LatとLngの値を使ってポイントを取得できます。ここで

Answer 2

public class PathToDestination { 

    private GoogleMap mMap; 
    private Context context; 
    private static final String API_KEY = "your key"; 

    private String pathColor = "#05b1fb";//default blue color 
    private int pathWidth = 5;//default is 5 
    private Polyline line; 
    private PolylineOptions polylineOptions; 

    public PathToDestination(Context context, GoogleMap mMap) { 
     this.context = context; 
     this.mMap = mMap; 
    } 

    public void setPathColor(String pathColor) { 
     this.pathColor = pathColor; 
    } 

    public void setPathWidth(int pathWidth) { 
     this.pathWidth = pathWidth; 
    } 

    public void drawPathBetween(@MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog) { 
     drawPathBetween(mode, sourcelat, sourcelog, destlat, destlog, null); 
    } 

    public void drawPathBetween(@MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog, MapModel[] waypoints) { 
     String urlStr = makeURL(mode, sourcelat, sourcelog, destlat, destlog, waypoints); 
     new ConnectAsyncTask(urlStr).execute(); 
    } 

    /*private String makeURL(double sourcelat, double sourcelog, double destlat, double destlog) { 
     return makeURL(sourcelat, sourcelog, destlat, destlog,); 
    }*/ 

    private String makeURL(@MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog, MapModel... waypoints) { 
     StringBuilder urlString = new StringBuilder(); 
     urlString.append("https://maps.googleapis.com/maps/api/directions/json"); 
     urlString.append("?origin=");// from 
     urlString.append(Double.toString(sourcelat)); 
     urlString.append(","); 
     urlString.append(Double.toString(sourcelog)); 
     if (waypoints != null && waypoints.length > 0) { 
      urlString.append("&waypoints=");// waypoints 
      for (int i = 0; i < waypoints.length; i++) { 
       MapModel coordinate = waypoints[i]; 
       urlString.append(coordinate.getLatitude()); 
       urlString.append(","); 
       urlString.append(coordinate.getLongitude()); 
       if (i < waypoints.length - 1) { 
        urlString.append("|"); 
       } 
      } 
     } 
     urlString.append("&destination=");// to 
     urlString.append(Double.toString(destlat)); 
     urlString.append(","); 
     urlString.append(Double.toString(destlog)); 
     urlString.append("&sensor=false"); 
     urlString.append("&mode=" + mode); 
     urlString.append("&alternatives=true"); 
     urlString.append("&key=" + API_KEY); 
     return urlString.toString(); 
    } 

    private void drawPath(String result) { 

     try { 
      //Tranform the string into a json object 
      final JSONObject json = new JSONObject(result); 
      JSONArray routeArray = json.getJSONArray("routes"); 
      JSONObject routes = routeArray.getJSONObject(0); 
      JSONObject overviewPolylines = routes.getJSONObject("overview_polyline"); 
      String encodedString = overviewPolylines.getString("points"); 
      List<LatLng> list = null; 

      if (polylineOptions == null) { 
       polylineOptions = new PolylineOptions() 
         .width(pathWidth) 
         .color(Color.parseColor(pathColor)) //Google maps blue color 
         .geodesic(true); 
      } 

      list = decodePoly(encodedString); 
      polylineOptions.addAll(list); 

      if (line == null) { 
       line = mMap.addPolyline(polylineOptions); 
      } 

      line.setPoints(list); 
      /* 
      for(int z = 0; z<list.size()-1;z++){ 
       LatLng src= list.get(z); 
       LatLng dest= list.get(z+1); 
       Polyline line = mMap.addPolyline(new PolylineOptions() 
       .add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude)) 
       .width(2) 
       .color(Color.BLUE).geodesic(true)); 
      } 
      */ 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
    } 

    public void drawPathFromEncodedPolyline(String encodedPolyline) { 

//  try { 
     //Tranform the string into a json object 
//   final JSONObject json = new JSONObject(result); 
//   JSONArray routeArray = json.getJSONArray("routes"); 
//   JSONObject routes = routeArray.getJSONObject(0); 
//   JSONObject overviewPolylines = routes.getJSONObject("overview_polyline"); 
//   String encodedString = overviewPolylines.getString("points"); 
     List<LatLng> list = decodePoly(encodedPolyline); 
     Polyline line = mMap.addPolyline(new PolylineOptions() 
       .addAll(list) 
       .width(5) 
       .color(Color.parseColor("#05b1fb"))//Google maps blue color 
       .geodesic(true) 
     ); 
      /* 
      for(int z = 0; z<list.size()-1;z++){ 
       LatLng src= list.get(z); 
       LatLng dest= list.get(z+1); 
       Polyline line = mMap.addPolyline(new PolylineOptions() 
       .add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude)) 
       .width(2) 
       .color(Color.BLUE).geodesic(true)); 
      } 
      */ 
//  } catch (JSONException e) { 
//   e.printStackTrace(); 
//  } 
    } 

    private List<LatLng> decodePoly(String encoded) { 

     List<LatLng> poly = new ArrayList<LatLng>(); 
     int index = 0, len = encoded.length(); 
     int lat = 0, lng = 0; 

     while (index < len) { 
      int b, shift = 0, result = 0; 
      do { 
       b = encoded.charAt(index++) - 63; 
       result |= (b & 0x1f) << shift; 
       shift += 5; 
      } while (b >= 0x20); 
      int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1)); 
      lat += dlat; 

      shift = 0; 
      result = 0; 
      do { 
       b = encoded.charAt(index++) - 63; 
       result |= (b & 0x1f) << shift; 
       shift += 5; 
      } while (b >= 0x20); 
      int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1)); 
      lng += dlng; 

      LatLng p = new LatLng((((double) lat/1E5)), 
        (((double) lng/1E5))); 
      poly.add(p); 
     } 

     return poly; 
    } 


    private class ConnectAsyncTask extends AsyncTask<Void, Void, String> { 
     private ProgressDialog progressDialog; 
     String url; 

     ConnectAsyncTask(String urlPass) { 
      url = urlPass; 
     } 

     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 
      if ((Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && 
        !((Activity) context).isDestroyed()) || 
        !((Activity) context).isFinishing()) { 
       progressDialog = new ProgressDialog(context); 
//    progressDialog.setMessage("Fetching route, Please wait..."); 
//    progressDialog.setIndeterminate(true); 
//    progressDialog.show(); 
      } 
     } 

     @Override 
     protected String doInBackground(Void... params) { 
      HttpURLConnection conn = null; 
      StringBuilder jsonResults = new StringBuilder(); 
      try { 
       URL url = new URL(this.url); 
       conn = (HttpURLConnection) url.openConnection(); 
       InputStreamReader in = new InputStreamReader(conn.getInputStream()); 

       // Load the results into a StringBuilder 
       int read; 
       char[] buff = new char[1024]; 
       while ((read = in.read(buff)) != -1) { 
        jsonResults.append(buff, 0, read); 
       } 
      } catch (MalformedURLException e) { 
       return jsonResults.toString(); 
      } catch (IOException e) { 
       return jsonResults.toString(); 
      } finally { 
       if (conn != null) { 
        conn.disconnect(); 
       } 
      } 

      return jsonResults.toString(); 
     } 

     @Override 
     protected void onPostExecute(String result) { 
      super.onPostExecute(result); 

      if (progressDialog != null) { 
       progressDialog.hide(); 
      } 

      if (result != null) { 
       drawPath(result); 
      } 
     } 
    } 

    public void clearRoute() { 
     if (line != null) { 
      line.remove(); 
     } 
     line = null; 
     polylineOptions = null; 
    } 

} 

MapModelあなたは緯度経度のリストをしたい場合は、簡単に

drawPathFromEncodedPolyline（文字列encodedPolyline） メソッドからのことを得ることができるインタフェース

public interface MapModel { 
    double getLatitude(); 
    double getLongitude(); 
} 

です。

他のマップ機能では、hereと表示されます。