Android So zeigen Sie die Route zwischen Markierungen auf Google Maps an

Ich erstelle eine App, die den Standort des Benutzers anzeigt und diesen mit einem Marker markiert. Nachdem sich der Benutzer bewegt hat. Der Marker wird entfernt und ein neuer Marker erstellt. Jetzt. Ich möchte Markierungen an Punkt A und Punkt B in die App einbauen und die Route auf der Karte anzeigen. Es wird die nächstgelegene Straße auf der Karte verwendet. Ich habe einige Nachforschungen angestellt, aber nur alten Code gefunden, der vor 5 Jahren erstellt wurde. Könnte jemand so freundlich sein, mich durch diese Sache zu führen.

Der Punkt A und der Punkt B befinden sich in der LocationChanged-Methode.

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;

import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

import android.content.Context;
import android.content.Intent;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v4.app.FragmentActivity;
import android.widget.Toast;

public class MainActivity extends FragmentActivity implements LocationListener {
    private GoogleMap map;
    private LocationManager locationManager;
    private String provider;
    LatLng coordinate;
    Marker startPerc;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
        boolean enabledGPS = service
                .isProviderEnabled(LocationManager.GPS_PROVIDER);
        boolean enabledWiFi = service
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        // Check if enabled and if not send user to the GSP settings
        // Better solution would be to display a dialog and suggesting to 
        // go to the settings
        if (!enabledGPS) {
            Toast.makeText(this, "GPS signal not found", Toast.LENGTH_LONG).show();
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    // Define the criteria how to select the location provider -> use
    // default
    Criteria criteria = new Criteria();
    provider = locationManager.getBestProvider(criteria, false);
    Location location = locationManager.getLastKnownLocation(provider);

    // Initialize the location fields
    if (location != null) {
        Toast.makeText(this, "Selected Provider " + provider,
                Toast.LENGTH_SHORT).show();
        onLocationChanged(location);
    } else {

        //do something
    }


}

/* Request updates at startup */
@Override
protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(provider, 300, 1, this);
}

/* Remove the locationlistener updates when Activity is paused */
@Override
protected void onPause() {
    super.onPause();
    locationManager.removeUpdates(this);
}

@Override
public void onLocationChanged(Location location) {

    double lat =  location.getLatitude();
    double lng = location.getLongitude();
    Toast.makeText(this, "Location " + lat+","+lng,
            Toast.LENGTH_LONG).show();
    LatLng coordinate = new LatLng(lat, lng);
    Toast.makeText(this, "Location " + coordinate.latitude+","+coordinate.longitude,
            Toast.LENGTH_LONG).show();
    if(map!=null){
        map.clear();
    }
    //map.clear();
    GoogleMap map;
    if(startPerc!=null){
        startPerc.remove();
    }
    map = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
    startPerc = map.addMarker(new MarkerOptions()
    .position(coordinate)
      .title("Start")
      .snippet("Your Position")
      .icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher)));
    map.moveCamera(CameraUpdateFactory.newLatLngZoom(coordinate, 20));



    map.addMarker(new MarkerOptions()
                    .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE))
                    .position(new LatLng(3.214732, 101.747047))
                    .title("Point A")
                    .snippet("Bus Stop")
                    .flat(true));

    map.addMarker(new MarkerOptions()
                    .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE))
                    .position(new LatLng(3.214507, 101.749697))
                    .title("Point B")
                    .snippet("Bus Stop")
                    .flat(true));



startPerc.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher));

}


@ Override
public void onProviderDisabled(String provider) {
    Toast.makeText(this, "Enabled new provider " + provider,
            Toast.LENGTH_SHORT).show();

}


@Override
public void onProviderEnabled(String provider) {
    Toast.makeText(this, "Disabled provider " + provider,
            Toast.LENGTH_SHORT).show();

}


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

}
void Delay(int Seconds){
    long Time = 0;
    Time = System.currentTimeMillis();
    while(System.currentTimeMillis() < Time+(Seconds*1000));
}
}

Neuer Code von K Neeraj. Es stürzt leider immer noch ab, bitte überprüfen.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.json.JSONObject;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;

import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;

import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.widget.Toast;

public class MainActivity extends FragmentActivity implements LocationListener {
    private GoogleMap map;
    private LocationManager locationManager;
    private String provider;
    LatLng coordinate;
    Marker startPerc;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
        boolean enabledGPS = service
                .isProviderEnabled(LocationManager.GPS_PROVIDER);
        boolean enabledWiFi = service
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        // Check if enabled and if not send user to the GSP settings
        // Better solution would be to display a dialog and suggesting to 
        // go to the settings
        if (!enabledGPS) {
            Toast.makeText(this, "GPS signal not found", Toast.LENGTH_LONG).show();
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        // Define the criteria how to select the location provider -> use
        // default
        Criteria criteria = new Criteria();
        provider = locationManager.getBestProvider(criteria, false);
        Location location = locationManager.getLastKnownLocation(provider);



        // Initialize the location fields
        if (location != null) {
            Toast.makeText(this, "Selected Provider " + provider,
                    Toast.LENGTH_SHORT).show(); 
            onLocationChanged(location);
        } else {

        //do something
    }


}


/* Request updates at startup */
@Override
protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(provider, 300, 1, this);
}

/* Remove the locationlistener updates when Activity is paused */
@Override
protected void onPause() {
    super.onPause();
    locationManager.removeUpdates(this);
}

@Override
public void onLocationChanged(Location location) {

    double lat =  location.getLatitude();
    double lng = location.getLongitude();
    Toast.makeText(this, "Location " + lat+","+lng,
            Toast.LENGTH_LONG).show();
    LatLng coordinate = new LatLng(lat, lng);
    Toast.makeText(this, "Location " + coordinate.latitude+","+coordinate.longitude,
            Toast.LENGTH_LONG).show();



    if(map!=null){
        map.clear();
    }

    GoogleMap map;
    if(startPerc!=null){
        startPerc.remove();
    }
    map = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
    startPerc = map.addMarker(new MarkerOptions()
    .position(coordinate)
      .title("Start")
      .snippet("Your Position")
      .icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher)));
    map.moveCamera(CameraUpdateFactory.newLatLngZoom(coordinate, 12));




    startPerc.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher));

 // Assign your origin and destination
 // These points are your markers coordinates
 LatLng origin = new LatLng(3.214732, 101.747047);
 LatLng dest = new LatLng(3.214507, 101.749697);

 // Getting URL to the Google Directions API
 String url = getDirectionsUrl(origin, dest);

 DownloadTask downloadTask = new DownloadTask();

 // Start downloading json data from Google Directions API
 downloadTask.execute(url);
 }


 private String getDirectionsUrl(LatLng origin,LatLng dest){


     // Origin of route
     String str_origin = "origin="+origin.latitude+","+origin.longitude;

     // Destination of route
     String str_dest = "destination="+dest.latitude+","+dest.longitude;

     // Sensor enabled
     String sensor = "sensor=false";

     // Building the parameters to the web service
     String parameters = str_origin+"&"+str_dest+"&"+sensor;

     // Output format
     String output = "json";

     // Building the url to the web service
     String url = "https://maps.googleapis.com/maps/api/directions/"+output+"?"+parameters;

     return url;
 }



 /** A method to download json data from url */
     private String downloadUrl(String strUrl) throws IOException{
         String data = "";
         InputStream iStream = null;
         HttpURLConnection urlConnection = null;
         try{
             URL url = new URL(strUrl);

         // Creating an http connection to communicate with url
         urlConnection = (HttpURLConnection) url.openConnection();

         // Connecting to url
         urlConnection.connect();

         // Reading data from url
         iStream = urlConnection.getInputStream();

         BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

         StringBuffer sb = new StringBuffer();

         String line = "";
         while( ( line = br.readLine()) != null){
             sb.append(line);
         }

         data = sb.toString();

         br.close();

     }catch(Exception e){
         Log.d("Exception while downloading url", e.toString());
     }finally{
         iStream.close();
         urlConnection.disconnect();
     }
     return data;
 }

 // Fetches data from url passed
 private class DownloadTask extends AsyncTask<String, Void, String>{

     // Downloading data in non-ui thread
     @Override
     protected String doInBackground(String... url) {

         // For storing data from web service
         String data = "";

         try{
             // Fetching the data from web service
             data = downloadUrl(url[0]);
         }catch(Exception e){
             Log.d("Background Task",e.toString());
         }
         return data;
     }

     // Executes in UI thread, after the execution of
     // doInBackground()
     @Override
     protected void onPostExecute(String result) {
         super.onPostExecute(result);

         ParserTask parserTask = new ParserTask();

         // Invokes the thread for parsing the JSON data
         parserTask.execute(result);
     }
 }

 /** A class to parse the Google Places in JSON format */
 private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String,String>>> >{

     // Parsing the data in non-ui thread
     @Override
     protected List<List<HashMap<String, String>>> doInBackground(String... jsonData) {

         JSONObject jObject;
         List<List<HashMap<String, String>>> routes = null;

         try{
             jObject = new JSONObject(jsonData[0]);
             DirectionsJSONParser parser = new DirectionsJSONParser();

             // Starts parsing data
             routes = parser.parse(jObject);
         }catch(Exception e){
             e.printStackTrace();
         }
         return routes;
     }

     // Executes in UI thread, after the parsing process
     @Override
     protected void onPostExecute(List<List<HashMap<String, String>>> result) {
         ArrayList<LatLng> points = null;
         PolylineOptions lineOptions = null;
         MarkerOptions markerOptions = new MarkerOptions();

         // Traversing through all the routes
         for(int i=0;i<result.size();i++){
             points = new ArrayList<LatLng>();
             lineOptions = new PolylineOptions();

             // Fetching i-th route
             List<HashMap<String, String>> path = result.get(i);

             // Fetching all the points in i-th route
             for(int j=0;j<path.size();j++){
                 HashMap<String,String> point = path.get(j);

                 double lat = Double.parseDouble(point.get("lat"));
                 double lng = Double.parseDouble(point.get("lng"));
                 LatLng position = new LatLng(lat, lng);

                 points.add(position);
             }

             // Adding all the points in the route to LineOptions
             lineOptions.addAll(points);
             lineOptions.width(2);
             lineOptions.color(Color.RED);
         }

         // Drawing polyline in the Google Map for the i-th route
         map.addPolyline(lineOptions);
     }
 }




@ Override
public void onProviderDisabled(String provider) {
    Toast.makeText(this, "Enabled new provider " + provider,
            Toast.LENGTH_SHORT).show();

}


@Override
public void onProviderEnabled(String provider) {
    Toast.makeText(this, "Disabled provider " + provider,
            Toast.LENGTH_SHORT).show();

}


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

}
void Delay(int Seconds){
    long Time = 0;
    Time = System.currentTimeMillis();
    while(System.currentTimeMillis() < Time+(Seconds*1000));
}
}

Dann habe ich eine neue DirectionJSONParser.java erstellt

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.google.android.gms.maps.model.LatLng;

public class DirectionsJSONParser {

    /** Receives a JSONObject and returns a list of lists containing latitude and longitude */
    public List<List<HashMap<String,String>>> parse(JSONObject jObject){

        List<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String,String>>>() ;
        JSONArray jRoutes = null;
        JSONArray jLegs = null;
        JSONArray jSteps = null;

        try {

            jRoutes = jObject.getJSONArray("routes");

            /** Traversing all routes */
            for(int i=0;i<jRoutes.length();i++){
                jLegs = ( (JSONObject)jRoutes.get(i)).getJSONArray("legs");
                List path = new ArrayList<HashMap<String, String>>();

                /** Traversing all legs */
                for(int j=0;j<jLegs.length();j++){
                    jSteps = ( (JSONObject)jLegs.get(j)).getJSONArray("steps");

                    /** Traversing all steps */
                    for(int k=0;k<jSteps.length();k++){
                        String polyline = "";
                        polyline = (String)((JSONObject)((JSONObject)jSteps.get(k)).get("polyline")).get("points");
                        List<LatLng> list = decodePoly(polyline);

                    /** Traversing all points */
                    for(int l=0;l<list.size();l++){
                        HashMap<String, String> hm = new HashMap<String, String>();
                        hm.put("lat", Double.toString(((LatLng)list.get(l)).latitude) );
                        hm.put("lng", Double.toString(((LatLng)list.get(l)).longitude) );
                        path.add(hm);
                    }
                }
            routes.add(path);
        }
    }

} catch (JSONException e) {
    e.printStackTrace();
}catch (Exception e){
}

return routes;
}
/**
* Method to decode polyline points
* Courtesy : http://jeffreysambells.com/2010/05/27/decoding-polylines-from-google-maps-direction-api-with-java
* */
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;
}
}