Lifecycle aware location observer.

LocationObserver.java

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.IntentSender;
import android.content.pm.PackageManager;
import android.os.Looper;

import androidx.core.app.ActivityCompat;
import androidx.lifecycle.Lifecycle;
import androidx.lifecycle.LifecycleObserver;
import androidx.lifecycle.OnLifecycleEvent;

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.LocationServices;
import com.google.android.gms.location.LocationSettingsRequest;
import com.google.android.gms.location.LocationSettingsStates;
import com.google.android.gms.location.SettingsClient;

import timber.log.Timber;

import static cmyap.mypackage.ui.MainActivity.RESOLVE_LOCATION_PERMISSION_RESOLUTION;


class LocationObserver implements LifecycleObserver {

    private Activity activity;
    private final FusedLocationProviderClient fusedLocationProviderClient;
    private final LocationCallback locationCallback;

    public LocationObserver(Activity activity, LocationCallback locationCallback) {
        this.activity = activity;
        this.fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(activity);
        this.locationCallback = locationCallback;
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    @SuppressLint("BinaryOperationInTimber")
    private void checkIfLocationSettingsAreOkayOrResolveThem() {

        LocationRequest locationRequest = getLocationRequest();

        LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
                .addLocationRequest(locationRequest);

        SettingsClient client = LocationServices.getSettingsClient(activity);
        client.checkLocationSettings(builder.build()).addOnSuccessListener(locationSettingsResponse -> {
            LocationSettingsStates states = locationSettingsResponse.getLocationSettingsStates();
            Timber.e("GPS Present: " + states.isGpsPresent());
            Timber.e("Location Present: " + states.isLocationPresent());
            Timber.e("GPS Usable: " + states.isGpsUsable());
            Timber.e("Location Usable: " + states.isLocationUsable());
        }).addOnFailureListener(e -> {
            Timber.e(e);
            if (e instanceof ResolvableApiException) {
                try {
                    ResolvableApiException resolvable = (ResolvableApiException) e;
                    resolvable.startResolutionForResult(activity, RESOLVE_LOCATION_PERMISSION_RESOLUTION);
                } catch (IntentSender.SendIntentException sendEx) {
                    Timber.e(sendEx);
                } catch(NullPointerException ex) {
                    Timber.e(ex);
                }
            }
        });

    }

    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    public void connectListener() {
        if (ActivityCompat.checkSelfPermission(activity, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(activity, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            fusedLocationProviderClient.requestLocationUpdates(getLocationRequest(), locationCallback, Looper.getMainLooper());
        }
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
    public void disconnectListener() {
        fusedLocationProviderClient.removeLocationUpdates(locationCallback);
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    public void clearContext() {
        activity = null;
    }

    private LocationRequest getLocationRequest() {
        LocationRequest locationRequest = LocationRequest.create();
        locationRequest.setInterval(3000);
        locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        locationRequest.setExpirationDuration(1800000);
        return locationRequest;
    }
}