Get current gps location android studio

Question

I am trying to write an android app, clearly, that uses the user's location to place a marker on a map activity or in this case print the latitude and longitude. However, I cannot find a tutorial or previous question that works for me. I am looking for the absolute simplest way to get the user's current location, using gps, in the form of a Location object or latitude and longitude. My current code is as follows, directly from this tutorial :

public class MainActivity extends AppCompatActivity
        implements ConnectionCallbacks, OnConnectionFailedListener, LocationListener {
    private TextView lat, lng;
    private GoogleApiClient mGoogleApiClient;
    private Location mCurrentLocation;
    private boolean mRequestingLocationUpdates;
    private LocationRequest mLocationRequest;

    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lat = (TextView) findViewById(R.id.lat);
        lng = (TextView) findViewById(R.id.lng);

        // 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
    public void onResume() {
        super.onResume();
        if (mGoogleApiClient.isConnected() && !mRequestingLocationUpdates) {
            startLocationUpdates();
        }
    }

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

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

    @Override
    public void onConnected(Bundle bundle) {
        mCurrentLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);
        if (mCurrentLocation != null) {
            lat.setText(String.valueOf("Lat: " + mCurrentLocation.getLatitude()));
            lng.setText(String.valueOf("Lng: " + mCurrentLocation.getLongitude()));
        }
        else
            Log.i("Problem", "mCurrentLocation is null");

        if (mRequestingLocationUpdates) {
            startLocationUpdates();
        }
    }

    protected void startLocationUpdates() {
        LocationServices.FusedLocationApi.requestLocationUpdates(
                mGoogleApiClient, mLocationRequest, this);
    }

    @Override
    public void onLocationChanged(Location location) {
        mCurrentLocation = location;
        updateUI();
    }

    private void updateUI() {
        lat.setText(String.valueOf("Lat: " + mCurrentLocation.getLatitude()));
        lng.setText(String.valueOf("Lng: " + mCurrentLocation.getLongitude()));
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }
}

and my AndroidManifest.xml is:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.root.locationtest">

    <meta-data android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="LocationTest"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

I always seem to get the log message "mCurrentLocation is null", so nothing in the app changes. There is also a warning on the line mCurrentLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient); that says "Call requires permission that may be rejected by the user." Any help is appreciated, thank you in advance.

EDIT: I surrounded all the lines with the "Call requires permission that may be rejected by the user" with the if statement:

if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) ==
                PackageManager.PERMISSION_GRANTED)

which resolves this warning. However, permission is being denied in the onConnect() method, and mCurrentLocation is still null.

Answer 1

Call requires permission that may be rejected by the user. this error is due to android's higher version that are required to get permission from user at run time. Just declaring in manifest would not help. So you need to add code for permissions.

if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // TODO: Consider calling
        //    ActivityCompat#requestPermissions
        // here to request the missing permissions, and then overriding
        //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
        //                                          int[] grantResults)
        // to handle the case where the user grants the permission. See the documentation
        // for ActivityCompat#requestPermissions for more details.
        return;
    }