String.xml

<resources>
    <string name="app_name">FusedLocationProviderClientDemo</string>
    <string name="action_settings">Settings</string>

    <string name="latitude_label">Latitude</string>
    <string name="longitude_label">Longitude</string>
    <string name="last_update_time_label">Last location update time</string>

    <string name="start_updates">Start updates</string>
    <string name="stop_updates">Stop updates</string>

    <string name="location_settings_inadequate_warning">The location settings on the device are not
        adequate to run this sample. Fix in Settings.</string>

    <string name="permission_rationale">Location permission is needed for core functionality</string>
    <string name="permission_denied_explanation">Permission was denied, but is needed for core
        functionality.</string>
    <string name="settings">Settings</string>
</resources>


-----------------------------------------------
   Manifest permission
   <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
   ---------------------------------------------------------------------------
  build.gradle
      compile 'com.google.android.gms:play-services-location:11.0.0'
   --------------------------------------------------------------------------
   MainActivity.class

import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.IntentSender;
import android.content.pm.PackageManager;
import android.location.Location;
import android.net.Uri;
import android.os.Bundle;
import android.os.Looper;
import android.provider.Settings;
import android.support.annotation.NonNull;
import android.support.design.widget.Snackbar;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.common.api.ResolvableApiException;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.location.LocationSettingsRequest;
import com.google.android.gms.location.LocationSettingsResponse;
import com.google.android.gms.location.LocationSettingsStatusCodes;
import com.google.android.gms.location.SettingsClient;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getSimpleName();

    private static final int REQUEST_PERMISSIONS_REQUEST_CODE = 34;
    private static final int REQUEST_CHECK_SETTINGS = 0x1;

    /**
     * The desired interval for location updates. Inexact. Updates may be more or less frequent.
     */
    private static final long UPDATE_INTERVAL_IN_MILLISECONDS = 5000;

    /**
     * The fastest rate for active location updates. Exact. Updates will never be more frequent than this value.
     */
    private static final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS = UPDATE_INTERVAL_IN_MILLISECONDS / 2;


    /**
     * Provides access to the Fused Location Provider API.
     */
    private FusedLocationProviderClient mFusedLocationClient;

    /**
     * Provides access to the Location Settings API.
     */
    private SettingsClient mSettingsClient;

    /**
     * Stores parameters for requests to the FusedLocationProviderApi.
     */
    private LocationRequest mLocationRequest;

    /**
     * Stores the types of location services the client is interested in using. Used for checking
     * settings to determine if the device has optimal location settings.
     */
    private LocationSettingsRequest mLocationSettingsRequest;

    /**
     * Callback for Location events.
     */
    private LocationCallback mLocationCallback;

    /**
     * Represents a geographical location.
     */
    private Location mCurrentLocation;

    // UI Widgets.
    private Button mStartUpdatesButton;
    private Button mStopUpdatesButton;
    private TextView mLastUpdateTimeTextView;
    private TextView mLatitudeTextView;
    private TextView mLongitudeTextView;

    // Labels.
    private String mLatitudeLabel;
    private String mLongitudeLabel;
    private String mLastUpdateTimeLabel;

    /**
     * Tracks the status of the location updates request. Value changes when the user presses the
     * Start Updates and Stop Updates buttons.
     */
    private Boolean mRequestingLocationUpdates;

    /**
     * Time when the location was updated represented as a String.
     */
    private String mLastUpdateTime;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        // Locate the UI widgets.
        mStartUpdatesButton = (Button) findViewById(R.id.start_updates_button);
        mStopUpdatesButton = (Button) findViewById(R.id.stop_updates_button);
        mLatitudeTextView = (TextView) findViewById(R.id.latitude_text);
        mLongitudeTextView = (TextView) findViewById(R.id.longitude_text);
        mLastUpdateTimeTextView = (TextView) findViewById(R.id.last_update_time_text);

        // Set labels.
        mLatitudeLabel = getResources().getString(R.string.latitude_label);
        mLongitudeLabel = getResources().getString(R.string.longitude_label);
        mLastUpdateTimeLabel = getResources().getString(R.string.last_update_time_label);

        mRequestingLocationUpdates = false;
        mLastUpdateTime = "";

        mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
        mSettingsClient = LocationServices.getSettingsClient(this);

        // Kick off the process of building the LocationCallback, LocationRequest, and
        // LocationSettingsRequest objects.
        createLocationCallback();
        createLocationRequest();
        buildLocationSettingsRequest();
        if (!mRequestingLocationUpdates) {
            mRequestingLocationUpdates = true;
            setButtonsEnabledState();
            startLocationUpdates();
        }
    }

    /**
     * Sets up the location request. Android has two location request settings:
     * {@code ACCESS_COARSE_LOCATION} and {@code ACCESS_FINE_LOCATION}. These settings control
     * the accuracy of the current location. This sample uses ACCESS_FINE_LOCATION, as defined in
     * the AndroidManifest.xml.
     * <p/>
     * When the ACCESS_FINE_LOCATION setting is specified, combined with a fast update
     * interval (5 seconds), the Fused Location Provider API returns location updates that are
     * accurate to within a few feet.
     * <p/>
     * These settings are appropriate for mapping applications that show real-time location
     * updates.
     */
    private void createLocationRequest() {
        mLocationRequest = new LocationRequest();

        // Sets the desired interval for active location updates. This interval is
        // inexact. You may not receive updates at all if no location sources are available, or
        // you may receive them slower than requested. You may also receive updates faster than
        // requested if other applications are requesting location at a faster interval.
        mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);

        // Sets the fastest rate for active location updates. This interval is exact, and your
        // application will never receive updates faster than this value.
        mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);

        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    }

    /**
     * Creates a callback for receiving location events.
     */
    private void createLocationCallback() {
        mLocationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                super.onLocationResult(locationResult);

                mCurrentLocation = locationResult.getLastLocation();
                mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
                updateLocationUI();
            }
        };
    }

    /**
     * Uses a {@link com.google.android.gms.location.LocationSettingsRequest.Builder} to build
     * a {@link com.google.android.gms.location.LocationSettingsRequest} that is used for checking
     * if a device has the needed location settings.
     */
    private void buildLocationSettingsRequest() {
        LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
        builder.addLocationRequest(mLocationRequest);
        mLocationSettingsRequest = builder.build();
    }

    /**
     * Handles the Start Updates button and requests start of location updates. Does nothing if
     * updates have already been requested.
     */
    public void startUpdatesButtonHandler(View view) {
        if (!mRequestingLocationUpdates) {
            mRequestingLocationUpdates = true;
            setButtonsEnabledState();
            startLocationUpdates();
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            // Check for the integer request code originally supplied to startResolutionForResult().
            case REQUEST_CHECK_SETTINGS:
                switch (resultCode) {
                    case Activity.RESULT_OK:
                        Log.e(TAG, "User agreed to make required location settings changes.");
                        // Nothing to do. startLocationupdates() gets called in onResume again.
                        startLocationUpdates();
                        break;
                    case Activity.RESULT_CANCELED:
                        Log.e(TAG, "User chose not to make required location settings changes.");
                        startLocationUpdates();
                        mRequestingLocationUpdates = false;
                        updateUI();
                        break;
                }
                break;
        }
    }


    /**
     * Requests location updates from the FusedLocationApi. Note: we don't call this unless location
     * runtime permission has been granted.
     */
    private void startLocationUpdates() {
        // Begin by checking if the device has the necessary location settings.
        mSettingsClient.checkLocationSettings(mLocationSettingsRequest)
                .addOnSuccessListener(this, new OnSuccessListener<LocationSettingsResponse>() {
                    @Override
                    public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
                        Log.e(TAG, "All location settings are satisfied.");

                        //noinspection MissingPermission
                        mFusedLocationClient.requestLocationUpdates(mLocationRequest,
                                mLocationCallback, Looper.myLooper());

                        updateUI();
                    }
                })
                .addOnFailureListener(this, new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        int statusCode = ((ApiException) e).getStatusCode();
                        switch (statusCode) {
                            case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
                                Log.e(TAG, "Location settings are not satisfied. Attempting to upgrade " +
                                        "location settings ");
                                try {
                                    // Show the dialog by calling startResolutionForResult(), and check the
                                    // result in onActivityResult().
                                    ResolvableApiException rae = (ResolvableApiException) e;
                                    rae.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);
                                } catch (IntentSender.SendIntentException sie) {
                                    Log.e(TAG, "PendingIntent unable to execute request.");
                                }
                                break;
                            case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
                                String errorMessage = "Location settings are inadequate, and cannot be " +
                                        "fixed here. Fix in Settings.";
                                Log.e(TAG, errorMessage);
                                Toast.makeText(MainActivity.this, errorMessage, Toast.LENGTH_LONG).show();
                                mRequestingLocationUpdates = false;
                        }

                        updateUI();
                    }
                });
    }

    /**
     * Updates all UI fields.
     */
    private void updateUI() {
        setButtonsEnabledState();
        updateLocationUI();
    }

    /**
     * Disables both buttons when functionality is disabled due to insuffucient location settings.
     * Otherwise ensures that only one button is enabled at any time. The Start Updates button is
     * enabled if the user is not requesting location updates. The Stop Updates button is enabled
     * if the user is requesting location updates.
     */
    private void setButtonsEnabledState() {
        if (mRequestingLocationUpdates) {
            mStartUpdatesButton.setEnabled(false);
            mStopUpdatesButton.setEnabled(true);
        } else {
            mStartUpdatesButton.setEnabled(true);
            mStopUpdatesButton.setEnabled(false);
        }
    }

    /**
     * Sets the value of the UI fields for the location latitude, longitude and last update time.
     */
    private void updateLocationUI() {
        if (mCurrentLocation != null) {
            mLatitudeTextView.setText(String.format(Locale.ENGLISH, "%s: %f", mLatitudeLabel,
                    mCurrentLocation.getLatitude()));
            mLongitudeTextView.setText(String.format(Locale.ENGLISH, "%s: %f", mLongitudeLabel,
                    mCurrentLocation.getLongitude()));
            mLastUpdateTimeTextView.setText(String.format(Locale.ENGLISH, "%s: %s",
                    mLastUpdateTimeLabel, mLastUpdateTime));
        }
    }

    /**
     * Removes location updates from the FusedLocationApi.
     */
    private void stopLocationUpdates() {
        if (!mRequestingLocationUpdates) {
            Log.d(TAG, "stopLocationUpdates: updates never requested, no-op.");
            return;
        }

        // It is a good practice to remove location requests when the activity is in a paused or
        // stopped state. Doing so helps battery performance and is especially
        // recommended in applications that request frequent location updates.
        mFusedLocationClient.removeLocationUpdates(mLocationCallback)
                .addOnCompleteListener(this, new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                        mRequestingLocationUpdates = false;
                        setButtonsEnabledState();
                    }
                });
    }

    @Override
    public void onResume() {
        super.onResume();
        // Within {@code onPause()}, we remove location updates. Here, we resume receiving
        // location updates if the user has requested them.
        if (mRequestingLocationUpdates && checkPermissions()) {
            startLocationUpdates();
        } else if (!checkPermissions()) {
            requestPermissions();
        }

        updateUI();
    }

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

        // Remove location updates to save battery.
        stopLocationUpdates();
    }

    /**
     * Shows a {@link Snackbar}.
     *
     * @param mainTextStringId The id for the string resource for the Snackbar text.
     * @param actionStringId   The text of the action item.
     * @param listener         The listener associated with the Snackbar action.
     */
    private void showSnackbar(final int mainTextStringId, final int actionStringId,
                              View.OnClickListener listener) {
        Snackbar.make(
                findViewById(android.R.id.content),
                getString(mainTextStringId),
                Snackbar.LENGTH_INDEFINITE)
                .setAction(getString(actionStringId), listener).show();
    }

    /**
     * Return the current state of the permissions needed.
     */
    private boolean checkPermissions() {
        int permissionState = ActivityCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION);
        return permissionState == PackageManager.PERMISSION_GRANTED;
    }

    /**
     * Handles the Stop Updates button, and requests removal of location updates.
     */
    public void stopUpdatesButtonHandler(View view) {
        // It is a good practice to remove location requests when the activity is in a paused or
        // stopped state. Doing so helps battery performance and is especially
        // recommended in applications that request frequent location updates.
        stopLocationUpdates();
    }

    private void requestPermissions() {
        boolean shouldProvideRationale =
                ActivityCompat.shouldShowRequestPermissionRationale(this,
                        Manifest.permission.ACCESS_FINE_LOCATION);

        // Provide an additional rationale to the user. This would happen if the user denied the
        // request previously, but didn't check the "Don't ask again" checkbox.
        if (shouldProvideRationale) {
            Log.e(TAG, "Displaying permission rationale to provide additional context.");
            showSnackbar(R.string.permission_rationale,
                    android.R.string.ok, new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            // Request permission
                            ActivityCompat.requestPermissions(MainActivity.this,
                                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                                    REQUEST_PERMISSIONS_REQUEST_CODE);
                        }
                    });
        } else {
            Log.e(TAG, "Requesting permission");
            // Request permission. It's possible this can be auto answered if device policy
            // sets the permission in a given state or the user denied the permission
            // previously and checked "Never ask again".
            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    REQUEST_PERMISSIONS_REQUEST_CODE);
        }
    }

    /**
     * Callback received when a permissions request has been completed.
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        Log.e(TAG, "onRequestPermissionResult");
        if (requestCode == REQUEST_PERMISSIONS_REQUEST_CODE) {
            if (grantResults.length <= 0) {
                // If user interaction was interrupted, the permission request is cancelled and you
                // receive empty arrays.
                Log.e(TAG, "User interaction was cancelled.");
            } else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                if (mRequestingLocationUpdates) {
                    Log.e(TAG, "Permission granted, updates requested, starting location updates");
                    startLocationUpdates();
                }
            } else {
                // Permission denied.

                // Notify the user via a SnackBar that they have rejected a core permission for the
                // app, which makes the Activity useless. In a real app, core permissions would
                // typically be best requested during a welcome-screen flow.

                // Additionally, it is important to remember that a permission might have been
                // rejected without asking the user for permission (device policy or "Never ask
                // again" prompts). Therefore, a user interface affordance is typically implemented
                // when permissions are denied. Otherwise, your app could appear unresponsive to
                // touches or interactions which have required permissions.
                showSnackbar(R.string.permission_denied_explanation,
                        R.string.settings, new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                // Build intent that displays the App settings screen.
                                Intent intent = new Intent();
                                intent.setAction(
                                        Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                Uri uri = Uri.fromParts("package",
                                        BuildConfig.APPLICATION_ID, null);
                                intent.setData(uri);
                                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                startActivity(intent);
                            }
                        });
            }
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}