public class MapActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener  {

    private SupportMapFragment mapFragment;
    private GoogleMap map;
    private GoogleApiClient mGoogleApiClient;
    ArrayList markerPoints;
    private LocationRequest mLocationRequest;
    private long UPDATE_INTERVAL = 15000;  /* 15 secs */
    private long FASTEST_INTERVAL = 5000; /* 5 secs */
    private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

   // Marker marker;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (!isGooglePlayServicesAvailable()) {
            finish();
        }
        setContentView(R.layout.activity_map);

        getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
        getSupportActionBar().setDisplayShowCustomEnabled(true);
        getSupportActionBar().setCustomView(R.layout.custom_actionbar_maps);

        markerPoints = new ArrayList();
        mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
        if (mapFragment != null) {
            mapFragment.getMapAsync(new OnMapReadyCallback() {
                @Override
                public void onMapReady(GoogleMap map) {
                    loadMap(map);
                }
            });
        } else {
            Toast.makeText(this,"Error - Map Fragment was null!!", Toast.LENGTH_SHORT).show();
        }
    }

    protected void loadMap(GoogleMap googleMap) {
        map = googleMap;
        if (map != null) {
            // Map is ready
            Toast.makeText(this,"Map Fragment was loaded properly!", Toast.LENGTH_SHORT).show();
            map.setMyLocationEnabled(true);

            map.setOnMapClickListener(new GoogleMap.OnMapClickListener() {

                @Override
                public void onMapClick(LatLng point) {

                    // Already two locations
                    if(markerPoints.size()>1){
                        markerPoints.clear();
                        map.clear();
                    }

                    // Adding new item to the ArrayList
                    markerPoints.add(point);

                    // Creating MarkerOptions
                    MarkerOptions options = new MarkerOptions();

                    // Setting the position of the marker
                    options.position(point);

/**
 * For the start location, the color of marker is GREEN and
 * for the end location, the color of marker is RED.
 */
                    if(markerPoints.size()==1){
                        options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
                    }else if(markerPoints.size()==2){
                        options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
                    }

                    // Add new marker to the Google Map Android API V2
                    map.addMarker(options);

                    // Checks, whether start and end locations are captured
                    if(markerPoints.size() >= 2){
                        LatLng origin = (LatLng) markerPoints.get(0);
                        LatLng dest = (LatLng) markerPoints.get(1);

                        // 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);
                    }

                }
            });


            // Now that map has loaded, let's get our location!
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addApi(LocationServices.API)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this).build();

            connectClient();
        } else {
            Toast.makeText(this,"Error - Map was null!!", Toast.LENGTH_SHORT).show();
        }
    }

    protected void connectClient() {
        // Connect the client.
        if (isGooglePlayServicesAvailable() && mGoogleApiClient != null) {
            mGoogleApiClient.connect();
        }
    }

    /*
     * Called when the Activity becomes visible.
    */
    @Override
    protected void onStart() {
        super.onStart();
        connectClient();
    }

    /*
     * Called when the Activity is no longer visible.
     */
    @Override
    protected void onStop() {
        // Disconnecting the client invalidates it.
        if (mGoogleApiClient != null) {
            mGoogleApiClient.disconnect();
        }
        super.onStop();
    }

    /*
     * Handle results returned to the FragmentActivity by Google Play services
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // Decide what to do based on the original request code
        switch (requestCode) {

            case CONNECTION_FAILURE_RESOLUTION_REQUEST:
            /*
             * If the result code is Activity.RESULT_OK, try to connect again
             */
                switch (resultCode) {
                    case Activity.RESULT_OK:
                        mGoogleApiClient.connect();
                        break;
                }

        }
    }

// Fetches data from url passed


    private boolean isGooglePlayServicesAvailable() {
        // Check that Google Play services is available
        int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
        // If Google Play services is available
        if (ConnectionResult.SUCCESS == resultCode) {
            // In debug mode, log the status
            Log.d("Location Updates","Google Play services is available.");
            return true;
        } else {
            // Get the error dialog from Google Play services
            Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(resultCode, this,
                    CONNECTION_FAILURE_RESOLUTION_REQUEST);

            // If Google Play services can provide an error dialog
            if (errorDialog != null) {
                // Create a new DialogFragment for the error dialog
                ErrorDialogFragment errorFragment = new ErrorDialogFragment();
                errorFragment.setDialog(errorDialog);
                errorFragment.show(getSupportFragmentManager(),"Location Updates");
            }

            return false;
        }
    }



    /*
     * Called by Location Services when the request to connect the client
     * finishes successfully. At this point, you can request the current
     * location or start periodic updates
     */
    @Override
    public void onConnected(Bundle dataBundle) {
        // Display the connection status
        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (location != null) {
            Toast.makeText(this,"GPS location was found!", Toast.LENGTH_SHORT).show();
            LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
            CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 16);
            map.animateCamera(cameraUpdate);
            //marker = map.addMarker(new MarkerOptions().position(latLng).icon(BitmapDescriptorFactory.fromResource(R.drawable.vehicle_marker)).flat(true).anchor(0.5f,0.5f));
            startLocationUpdates();
        } else {
            Toast.makeText(this,"Current location was null, enable GPS on emulator!", Toast.LENGTH_SHORT).show();
        }
    }

    protected void startLocationUpdates() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
        mLocationRequest.setInterval(UPDATE_INTERVAL);
        mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
                mLocationRequest, this);
    }

    public void onLocationChanged(Location location) {
        // Report to the UI that the location was updated

        LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
       /* if(marker == null){
           *//* marker.remove();*//*
            marker = map.addMarker(new MarkerOptions().position(latLng).icon(BitmapDescriptorFactory.fromResource(R.drawable.vehicle_marker)));
        }

        marker.setPosition(latLng);
*/
        CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 16);
        map.animateCamera(cameraUpdate);



        String msg ="Updated Location:" +
                Double.toString(location.getLatitude()) +"," +
                Double.toString(location.getLongitude());
        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();

    }



    /*
     * Called by Location Services if the connection to the location client
     * drops because of an error.
     */
    @Override
    public void onConnectionSuspended(int i) {
        if (i == CAUSE_SERVICE_DISCONNECTED) {
            Toast.makeText(this,"Disconnected. Please re-connect.", Toast.LENGTH_SHORT).show();
        } else if (i == CAUSE_NETWORK_LOST) {
            Toast.makeText(this,"Network lost. Please re-connect.", Toast.LENGTH_SHORT).show();
        }
    }

    /*
     * Called by Location Services if the attempt to Location Services fails.
     */
    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        /*
         * Google Play services can resolve some errors it detects. If the error
         * has a resolution, try sending an Intent to start a Google Play
         * services activity that can resolve error.
         */
        if (connectionResult.hasResolution()) {
            try {
                // Start an Activity that tries to resolve the error
                connectionResult.startResolutionForResult(this,
                        CONNECTION_FAILURE_RESOLUTION_REQUEST);
                /*
                 * Thrown if Google Play services canceled the original
                 * PendingIntent
                 */
            } catch (IntentSender.SendIntentException e) {
                // Log the error
                e.printStackTrace();
            }
        } else {
            Toast.makeText(getApplicationContext(),
                   "Sorry. Location services not available to you", Toast.LENGTH_LONG).show();
        }
    }


    // Define a DialogFragment that displays the error dialog
    public static class ErrorDialogFragment extends DialogFragment {

        // Global field to contain the error dialog
        private Dialog mDialog;

        // Default constructor. Sets the dialog field to null
        public ErrorDialogFragment() {
            super();
            mDialog = null;
        }

        // Set the dialog to display
        public void setDialog(Dialog dialog) {
            mDialog = dialog;
        }

        // Return a Dialog to the DialogFragment.
        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            return mDialog;
        }
    }

    // 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 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();
                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(12);
                lineOptions.color(Color.RED);
                lineOptions.geodesic(true);

            }

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

    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;
    }
}

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

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

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



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 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 decodePoly(String encoded) {

        List poly = new ArrayList();
        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;
    }
}