Not getting Latitude and Longitude from LocationListener class

Question

I am having problem with LocationListener. Why is my code not getting the latitude and longitude coordinates in onLocationChange() method? It is passing the coordinates of latitude and longitude to be 0. Can any one point out the error in this code and the changes that needs to be done?

public class Login extends AppCompatActivity implements LocationListener {
    private EditText e_mail, pass_word;
    FirebaseAuth mAuth;
    FirebaseFirestore fStore;
    String userID;
    public static final String TAG = "TAG";

    protected LocationManager locationManager;
    protected LocationListener locationListener;
    protected Context context;

    private double lat;
    private double lng;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        e_mail = findViewById(R.id.emailLogin);
        pass_word = findViewById(R.id.password);
        Button btn_login = findViewById(R.id.btn_login);
        Button btn_sign = findViewById(R.id.btn_signup);


        fStore = FirebaseFirestore.getInstance();
        mAuth = FirebaseAuth.getInstance();

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);




        btn_login.setOnClickListener(v -> {
            String email= e_mail.getText().toString().trim();
            String password=pass_word.getText().toString().trim();

            if(email.isEmpty())
            {
                e_mail.setError("Email is empty");
                e_mail.requestFocus();
                return;
            }
            if(!Patterns.EMAIL_ADDRESS.matcher(email).matches())
            {
                e_mail.setError("Enter the valid email");
                e_mail.requestFocus();
                return;
            }
            if(password.isEmpty())
            {
                pass_word.setError("Password is empty");
                pass_word.requestFocus();
                return;
            }
            if(password.length()<6)
            {
                pass_word.setError("Length of password is more than 6");
                pass_word.requestFocus();
                return;
            }
            mAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener(task -> {

                if(task.isSuccessful())
                {
                    AlertDialog.Builder builder = new AlertDialog.Builder(Login.this);
                    builder.setTitle("Registration")
                            .setMessage("What do you want to register as ? ")
                            .setCancelable(false)
                            .setPositiveButton("Organization", new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialog, int which) {
                                    Intent organization = new Intent(Login.this,OrganizationPage.class);
                                    startActivity(organization);
                                    Login.this.finish();
                                }
                            })
                            .setNegativeButton("Volunteer", new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialog, int which) {

                                    uploadData();
                                    Intent volunteer = new Intent(Login.this,VolunteerPage.class);
                                    startActivity(volunteer);
                                    Login.this.finish();}
                            });
                    //Creating dialog box
                    AlertDialog dialog  = builder.create();
                    dialog.show();

                }
                else
                {
                    Toast.makeText(Login.this,
                            "Please Check Your login Credentials",
                            Toast.LENGTH_SHORT).show();
                }

            });



        });
        btn_sign.setOnClickListener(v -> {
            startActivity(new Intent(Login.this, Register.class));
        });
    }


    @Override
    public void onLocationChanged(@NonNull Location location) {
        lat =location.getLatitude();
        lng = location.getLongitude();
        Log.v("Activity location ", String.valueOf(lat)+"latitude of volunteer");
        Toast.makeText(this,lat+" Works "+lng,Toast.LENGTH_SHORT).show();
    }
    public void uploadData(){
        String name = username;

        double latitude = lat;
        double longitude = lng;

        Log.v("Activity location ", String.valueOf(latitude));



        userID = mAuth.getCurrentUser().getUid();
        CollectionReference collectionReference = fStore.collection("Volunteer data");
        Map<String,Object> user = new HashMap<>();
        user.put("timestamp", FieldValue.serverTimestamp());
        user.put("name",name);
        user.put("volunteerLatitude",latitude);
        user.put("volunteerLongitude",longitude);
        user.put("userid",userID);
        collectionReference.add(user)
                .addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
                    @Override
                    public void onSuccess(DocumentReference documentReference) {
                        Toast.makeText(getApplicationContext(),"Successfully Registered as Volunteer",Toast.LENGTH_SHORT).show();
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Toast.makeText(getApplicationContext(),"Error!",Toast.LENGTH_SHORT).show();
                    }
                });
    }
}

Answer 1

You need to add location in your manifest.xml like this:

<manifest ... >
  <!-- Always include this permission -->
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

  <!-- Include only if your app benefits from precise location access. -->
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
</manifest>