Question

Im new to android and i am trying to make a program that outputs the longitude and latitude integers to the screen inside text fields.

Ive have two edit text fields:

<EditText
        android:id="@+id/longitudeField"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <EditText 
        android:id="@+id/latitudeField"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="text"/>

I know have a java file that runs a class called EmergencyLocation.
In this file i set the longitude and latitude and try to output these to the screen via the edit text fields but every time i do this nothing comes up.

import android.app.Activity;
import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.content.Context;
import android.location.LocationManager;
import android.location.Criteria;

        public class EmergencyLocation extends Activity implements LocationListener 
        {
            private TextView latitudeField;
            private TextView longitudeField;
            private LocationManager locationManager;
            private String provider;

            @Override
            public void onCreate(Bundle savedInstanceState)
            {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.main);
                latitudeField = (TextView) findViewById(R.id.latitudeField);
                //logitudeField = (TextView) findViewById(R.id.????);

                locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

                Criteria criteria = new Criteria();
                provider = locationManager.getBestProvider(criteria, false);
                locationManager.requestLocationUpdates(provider, 0, 0, this);
                Location location = locationManager.getLastKnownLocation(provider);
                onLocationChanged(location);
            }

            @Override
            public void onDestroy()
            {
                super.onDestroy();
                locationManager.removeUpdates(this);
            }

            @Override
            public void onLocationChanged(Location location) 
            {
                if(location != null)
                {
                    System.out.println("Provider " + provider + " has been selected.");
                    int lat = (int) (location.getLatitude());
                    //int lng = (int) (location.getLongitude());
                    latitudeField.setText(String.valueOf(lat));
                    //longitudeField.setText(String.valueOf(lng));
                }
                else
                {
                    latitudeField.setText(String.valueOf("Provider not avaliable"));
                    //the same with long stuff
                }
            }
            @Override
            public void onProviderDisabled(String provider) {
                // TODO Auto-generated method stub

            }
            @Override
            public void onProviderEnabled(String provider) {
                // TODO Auto-generated method stub

            }
            @Override
            public void onStatusChanged(String provider, int status,
                    Bundle extras) {
                // TODO Auto-generated method stub

            } 
        }

as i said before im new to android and i think it is something very simple im missing.

thanks in advance

Answer 1

I’ve tested your app. It is working and location is updating. May be you forget to specify LOCATION-permisions in AndroidManifest.xml?

Also, here:

provider = locationManager.getBestProvider(criteria, false);

provider may be null. In this case you will receive an exception while trying to do

locationManager.requestLocationUpdates(provider, 0, 0, this);

So, you should check provider for “null” before calling requestLocationUpdates().

Also, is there any problem with longitude?