MapsActivity.java

package ie.doubleh.mapsdemo;

import android.content.pm.PackageManager;
import android.location.Location;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
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.MarkerOptions;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private static final int LOCATION_PERMISSION = 0;
    private static final int LOCATION_UPDATES_PERMISSION = 1;

    private GoogleMap mMap;
    private GoogleApiClient mGoogleApiClient;

    private LocationRequest mLocationRequest;
    private Location currentLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        buildGoogleApiClient();
        createLocationRequest();
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        if (currentLocation != null) {
            updateMapLocation();
        }
    }

    private void updateMapLocation() {
        LatLng currentLatLng = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        mMap.clear();
        mMap.addMarker(new MarkerOptions().position(currentLatLng).title("Current Location").icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)));
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLatLng, 12));
    }

    private void buildGoogleApiClient() {
        // Create an instance of GoogleAPIClient.
        if (mGoogleApiClient == null) {
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .build();
        }
    }

    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    protected void onPause() {
        super.onPause();
        stopLocationUpdates();
    }

    @Override
    public void onResume() {
        super.onResume();
        if (mGoogleApiClient.isConnected()) {
            startLocationUpdates();
        }
    }

    protected void stopLocationUpdates() {
        LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_PERMISSION);
        } else {
            currentLocation = LocationServices.FusedLocationApi.getLastLocation(
                    mGoogleApiClient);
            startLocationUpdates();
            if (mMap != null) {
                updateMapLocation();
            }
        }
    }

    protected void startLocationUpdates() {
        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_UPDATES_PERMISSION);
        } else {
            LocationServices.FusedLocationApi.requestLocationUpdates(
                    mGoogleApiClient, mLocationRequest, this);
        }
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode) {
            case LOCATION_PERMISSION:
            {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    onConnected(null);
                }
            }
            return;
            case LOCATION_UPDATES_PERMISSION:
            {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    startLocationUpdates();
                }
            }
        }
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        buildGoogleApiClient();
    }

    @Override
    public void onLocationChanged(Location location) {
        currentLocation = location;
        updateMapLocation();
    }

    protected void createLocationRequest() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(100);
        mLocationRequest.setSmallestDisplacement(1F);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    }
}