[Android] Empty variable in class. Where can there be an error?

Question

satellite navigation

Hello.
I ran into a problem I don't understand. There was a working class, no changes were made to it, at some point, it stopped working and produces an empty variable. The three of us looked into the class, but did not understand what could be wrong. I will be glad if someone helps, tk. I suspect that my eyes just "blurred" and do not see the obvious.
The source class from which the call originates.

package defond.keyfour.flyandroid;

import defond.keyfour.flyandroid.gps.GPSTracker;
import defond.keyfour.flyandroid.util.SystemUiHider;

import android.annotation.TargetApi;
import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;

import java.util.Timer;
import java.util.TimerTask;


/**
 * An example full-screen activity that shows and hides the system UI (i.e.
 * status bar and navigation/system bar) with user interaction.
 *
 * @see SystemUiHider
 */
public class FlightActivity extends Activity {

    GPSTracker gps = new GPSTracker(this);
    //double gpsLatitude = gps.getLatitude();
    double gpsLongitude = gps.getLongitude();
    double gpsAltitude = gps.getAltitude();
    double gpsBearing = gps.getBearing();
    double i=0;
    TextView testA;
    final Handler myHandler = new Handler();

    /*
    public FlightActivity(TextView testA) {
        this.testA = testA;
    }
    */

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_flight);
        testA = (TextView)findViewById(R.id.getAltPlan);

    }


    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        Timer myTimer = new Timer();
        myTimer.schedule(new TimerTask() {
            @Override
            public void run() {UpdateGUI();}
        }, 0, 1000);


    }

    private void UpdateGUI() {
        //i++;
        //i = 00;
        double gpsLatitude = gps.getLatitude();
        i = gpsLatitude;
        //testA.setText("sss");
        //testA.setText(String.valueOf(i));
        myHandler.post(myRunnable);
    }

    final Runnable myRunnable = new Runnable() {
        public void run() {
            testA.setText(String.valueOf(i));
            testA.invalidate();
        }
    };

}

The class in which the data from the GPS should be received.

package defond.keyfour.flyandroid.gps;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Address;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;

import defond.keyfour.flyandroid.FlightActivity;



public class GPSTracker extends Service implements LocationListener {

    private final Context mContext;

    // flag for GPS status
    boolean isGPSEnabled = false;

    // flag for network status
    boolean isNetworkEnabled = false;

    // flag for GPS status
    boolean canGetLocation = false;

    Location location; // location
    double latitude; // latitude
    double longitude; // longitude
    double altitude;
    public double speed;
    double bearing;



    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    public GPSTracker(FlightActivity context) {
        this.mContext = context;
        this.location = getLocation();
    }

    public Location getLocation() {
        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(LOCATION_SERVICE);

            // getting GPS status
            isGPSEnabled = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);

            // getting network status
            isNetworkEnabled = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (!isGPSEnabled && !isNetworkEnabled) {
                // no network provider is enabled
            } else {
                this.canGetLocation = true;
                // First get location from Network Provider
                if (isNetworkEnabled) {
                    locationManager.requestLocationUpdates(
                            LocationManager.NETWORK_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("Network", "Network");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                            altitude = location.getAltitude();
                            speed = location.getSpeed();
                            bearing = location.getBearing();
                        }
                    }
                }
                // if GPS Enabled get lat/long using GPS Services
                if (isGPSEnabled) {
                    if (location == null) {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            location = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                                altitude = location.getAltitude();
                                speed = location.getSpeed();
                                bearing = location.getBearing();
                            }
                        }
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }

    /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in your app
     * */
    public void stopUsingGPS(){
        if(locationManager != null){
            locationManager.removeUpdates(GPSTracker.this);
        }
    }

    /**
     * Function to get latitude
     * */
    public double getLatitude(){
        if(location != null){
            latitude = location.getLatitude();
        }
        else
        {
            //определяли определяли... Да не определили
            latitude = 999.999;
        }

        // return latitude
        return latitude;
    }

    /**
     * Function to get longitude
     * */
    public double getLongitude(){
        if(location != null){
            longitude = location.getLongitude();
        }

        // return longitude
        return longitude;
    }

    public double getAltitude(){
        if(location != null){
            altitude = location.getAltitude();
        }

        // return
        return altitude;
    }

    public double getSpeed() {
        if(location != null){
            speed = location.getSpeed();
        }
        return speed;
    }

    public double getBearing(){
        if(location != null){
            bearing = location.getBearing();
        }
        return bearing;
    }

    /**
     * Function to check GPS/wifi enabled
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    /**
     * Function to show settings alert dialog
     * On pressing Settings button will lauch Settings Options
     * */
    public void showSettingsAlert(){
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        // Setting Dialog Title
        alertDialog.setTitle("GPS is settings");

        // Setting Dialog Message
        alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing Settings button
        alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });

        // on pressing cancel button
        alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });

        // Showing Alert Message
        alertDialog.show();
    }

    @Override
    public void onLocationChanged(Location location) {
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

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

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}