GPS sensor locking when sensor is off

Question

I’m making an app that reads GPS coordinates.

When the sensor is on and running, the app pulls the information right, but when the sensor is off, the app hangs when I try to read the coordinates

package com.example.dfabr.primeiroprograma;

import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.util.List;

public class telaInformacao extends AppCompatActivity implements LocationListener {
        Button btnReceberCoordenadas;
        TextView receberCoordenadas;
        public TextView txtCidade;
        public TextView txtEStado;
        public TextView txtPais;


        private Address endereco;


        double latitude;
        double longitude;

        public static final int PREMISSAO =1;
        Location location = null;


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            getSupportActionBar().hide();
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_tela_informacao);

            btnReceberCoordenadas = (Button)findViewById(R.id.btnReceberCoordenadas);
            receberCoordenadas = (TextView)findViewById(R.id.receberCoordenadas);
            txtCidade = (TextView)findViewById(R.id.txtCidade);
            txtEStado = (TextView)findViewById(R.id.textEstado);
            txtPais = (TextView)findViewById(R.id.textPais);


            btnReceberCoordenadas.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(telaInformacao.this, "Suas Coordenadas Foram Geradas Com Sucesso", Toast.LENGTH_LONG).show();
                    lerCoordenadas();
                }
            });
        }


        private void lerCoordenadas(){
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED){
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION},PREMISSAO);
            }else{
                LocationManager locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
                boolean gps = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

                if (gps){
                    if (location == null) {
                        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                    }
                    if (location != null){
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                        Log.i("Coordenadas", "Latitude: \n" + latitude + "Longitude: \n " + longitude);
                        receberCoordenadas.setText("Latitude: " + latitude + "\n\nLongitude: " + longitude);

                    }
                }else
                    Toast.makeText(telaInformacao.this, "GPS desativado", Toast.LENGTH_LONG).show();
                try {
                    endereco = buscarEndereco(latitude,longitude);
                    txtCidade.setText("Bairro:  " + endereco.getSubLocality());
                    txtEStado.setText("Estado:  " + endereco.getAdminArea());
                    txtPais.setText("Pais:  " + endereco.getCountryName());

                }catch (IOException e){
                    Log.i("GPS", "GPS");
                }
            }
        }
        public Address buscarEndereco(double latitude, double longitude)
                throws IOException {
            Geocoder geocoder;
            Address address = null;
            List<Address> addresses;

            geocoder = new Geocoder(getApplicationContext());

            addresses = geocoder.getFromLocation(latitude, longitude, 1);
            if (addresses.size() > 0) {
                address = addresses.get(0);

            }
            return address;
        }

    /*public void onRequestPermissionResult(int requestCode, @NonNull String[] permission, @NonNull int[] grantresult) {

        switch (requestCode){
            case PREMISSAO:
                    if (permission[0].equalsIgnoreCase(Manifest.permission.ACCESS_FINE_LOCATION) &&
                            grantresult [0] == PackageManager.PERMISSION_GRANTED)
                        lerCoordenadas();
                    }

                    super.onRequestPermissionsResult(requestCode, permission, grantresult);
        }*/

        @Override
        public void onLocationChanged(Location location) {
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
        }

        @Override
        public void onProviderEnabled(String provider) {
        }

        @Override
        public void onProviderDisabled(String provider) {
        }
    }

Answer 1

The error is in the LSE because you say you have no gps but still try to load the location on the screen, the code should look like this:

private void lerCoordenadas(){
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION},PREMISSAO);
        }else{
            LocationManager locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
            boolean gps = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

            if (gps){
                if (location == null) {
                    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
                    location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                }
                if (location != null){
                    latitude = location.getLatitude();
                    longitude = location.getLongitude();
                    Log.i("Coordenadas", "Latitude: \n" + latitude + "Longitude: \n " + longitude);
                    receberCoordenadas.setText("Latitude: " + latitude + "\n\nLongitude: " + longitude);

                try {
                endereco = buscarEndereco(latitude,longitude);
                txtCidade.setText("Bairro:  " + endereco.getSubLocality());
                txtEStado.setText("Estado:  " + endereco.getAdminArea());
                txtPais.setText("Pais:  " + endereco.getCountryName());

                }catch (IOException e){
                Log.i("GPS", "GPS");
                }
                }
            }else
                Toast.makeText(telaInformacao.this, "GPS desativado", Toast.LENGTH_LONG).show();
        }
    }