Trace User's Location with Polylines in Google Map Android.

First You need to implement google map layout in your project which you have learnt in our previous tutorial if not than Click here.

What are PolyLines in Android?

Basically It draws lines between two consecutive points.We will use PolylineOptions which will store all the location updates and draws route on the map.

 

activity_main.xml

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="myproject.marshmallowsmaps.MapsActivity" />

 

MapsActivity.java

package myproject.marshmallowsmaps;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;

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

import java.util.ArrayList;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    LocationManager locationManager;
    private ArrayList<LatLng> points;
    Polyline line;

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

        points = new ArrayList<LatLng>();

        ActivityCompat.requestPermissions(MapsActivity.this, new String[]{Manifest.permission.INTERNET,
                Manifest.permission.ACCESS_COARSE_LOCATION,
                Manifest.permission.ACCESS_FINE_LOCATION}, 1);

        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    }

    @Override
    protected void onResume() {
        super.onResume();
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

    }

    @Override
    public void onMapReady(final GoogleMap googleMap) {

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                mMap = googleMap;
                if (ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                    return;
                }
                mMap.setMyLocationEnabled(true);
                LatLng My = new LatLng(location.getLatitude(), location.getLongitude());
                points.add(My);
                redrawLine();
                mMap.addMarker(new MarkerOptions().position(My).title("My Location"));
                mMap.moveCamera(CameraUpdateFactory.newLatLng(My));
                mMap.animateCamera(CameraUpdateFactory.zoomTo(12.0f));
            }

            private void redrawLine() {
                mMap.clear();  //clears all Markers and Polylines

                PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
                for (int i = 0; i < points.size(); i++) {
                    LatLng point = points.get(i);
                    options.add(point);
                }
                //  addMarker(); //add Marker in current position
                line = mMap.addPolyline(options); //add Polyline
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        });
    }
}

 

IF YOU HAVE ANY SUGGESTIONS OR ANY ERRORS WHILE IMPLEMENTING , FEEL FREE TO COMMENT BELOW.