Update location in background and check LocationSettings

I would like to update user's location every few minutes in background.
I used this sample code googlesamples/android-play-location
but changing it to use with Service

public class MyService extends Service implements
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener, ResultCallback<LocationSettingsResult>

but I can't check location settings

    protected void checkLocationSettings() {
        PendingResult<LocationSettingsResult> result =
                LocationServices.SettingsApi.checkLocationSettings(
                        mGoogleApiClient,
                        mLocationSettingsRequest
                );
        result.setResultCallback(this);
    }

    @Override
    public void onResult(LocationSettingsResult locationSettingsResult) {
        final Status status = locationSettingsResult.getStatus();
        switch (status.getStatusCode()) {
            case LocationSettingsStatusCodes.SUCCESS:
                Log.i(TAG, "All location settings are satisfied.");
                startLocationUpdates();
                break;
            case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
                Log.i(TAG, "Location settings are not satisfied. Show the user a dialog to" +
                        "upgrade location settings ");

                try {
                    // Show the dialog by calling startResolutionForResult(), and check the result
                    // in onActivityResult().
                    status.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);
                } catch (IntentSender.SendIntentException e) {
                    Log.i(TAG, "PendingIntent unable to execute request.");
                }
                break;
            case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
                Log.i(TAG, "Location settings are inadequate, and cannot be fixed here. Dialog " +
                        "not created.");
                break;
        }
    }

    @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.i(TAG, "User agreed to make required location settings changes.");
                        startLocationUpdates();
                        break;
                    case Activity.RESULT_CANCELED:
                        Log.i(TAG, "User chose not to make required location settings changes.");
                        break;
                }
                break;
        }
    }

Because this method requires an Activity

status.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);

and if I put the previous code in the MainActvity, I would not have the references to mGoogleApiClient and mLocationSettingsRequest

LocationServices.SettingsApi.checkLocationSettings(mGoogleApiClient, mLocationSettingsRequest);

I would like to upgrade and save in background the position even if the activity is destroyed.
Use the service is the correct way to do this?
And how do I check the location settings?

[EDIT]
I tried to use the PendingIntent and an IntentService

LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
                    mLocationRequest, mPendingIntent);

This method is suited for the background use cases, more specifically for receiving location updates, even when the app has been killed by the system.

What is the difference compared to the version with the Service and LocationListner?

I found a solution for my problem.
To access the Main Activity I used the method

MainActivity.getInstance()

MainActivity

public class MainActivity extends AppCompatActivity {
    private static MainActivity instance;

    public static MainActivity getInstance() {
        Log.i("MainActivity", "getInstance");
        return instance;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.i(TAG, "onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Instance of the MainActivity
        instance = this;
    }
    ...
   
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    Log.i(TAG, "onActivityResult");
    switch (requestCode) {
        // Check for the integer request code originally supplied to startResolutionForResult().
        case REQUEST_CHECK_SETTINGS:
            switch (resultCode) {
                case Activity.RESULT_OK:
                    Log.i(TAG, "User agreed to make required location settings changes.");
                    startService(intent);
                    break;
                case Activity.RESULT_CANCELED:
                    Log.i(TAG, "User chose not to make required location settings changes.");
                    break;
            }
            break;
        }
    }
}

Service

@Override
public void onResult(LocationSettingsResult locationSettingsResult) {
    final Status status = locationSettingsResult.getStatus();
    switch (status.getStatusCode()) {
        case LocationSettingsStatusCodes.SUCCESS:
            // All location settings are satisfied. The client can
            // initialize location requests here.
            Log.i(TAG, "All location settings are satisfied.");
            startLocationUpdates();
            break;
        case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
            // Location settings are not satisfied, but this can be fixed
            // by showing the user a dialog.
            Log.i(TAG, "Location settings are not satisfied. Show the user a dialog to " +
                    "upgrade location settings ");
            try {
                // Show the dialog by calling startResolutionForResult(),
                // and check the result in onActivityResult().
                status.startResolutionForResult(MainActivity.getInstance(), REQUEST_CHECK_SETTINGS);
            } catch (IntentSender.SendIntentException e) {
                // Ignore the error.
                Log.i(TAG, "PendingIntent unable to execute request.");
            }
            break;
        // The status will never be SETTINGS_CHANGE_UNAVAILABLE if use builder.setAlwaysShow(true);
        case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
            // Location settings are not satisfied. However, we have no way
            // to fix the settings so we won't show the dialog.
            Log.i(TAG, "Location settings are inadequate, and cannot be fixed here. Dialog " +
                    "not created.");
            break;
    }
}