在android中获取经度和经度programmaticaly总是得到GPS LastKnownLocation null

Question

大家好，我知道这个问题太旧了，而且有很多这个问题，但没有一个解决方案适合我。我正在尝试经纬度programmaticaly我尝试下面的代码，但是每次我得到的时候发生的是GPS LastKnownLocation = null 我的设备上启用了我的GPS，我在不同的设备上尝试了这个代码在其中一些我可以从GPS获得经度和经度，但对于他们中的大多数它显示为空。我不知道为什么这个代码在大多数情况下都失败了，如果你们中的任何一个人对此有所了解或有任何更好的方法，那么请告诉我，我花了差不多一个星期在上面的代码中挖掘出错了但是什么都没有帮助我。

更新 - 谷歌的FusedLocationApi是免费的，还是每天的请求数量有限？

public class GPSTracker extends Service implements LocationListener {
private final Context context;

boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;

Location location;

double latitude;
double longitude;

private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;

protected LocationManager locationManager;

public GPSTracker(Context context) {
    this.context = context;
    getLocation();
}

public Location getLocation() {
    try {
        locationManager = (LocationManager) context.getSystemService(LOCATION_SERVICE);
        isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if(!isGPSEnabled && !isNetworkEnabled) {

        } else {
            this.canGetLocation = true;
            if (isGPSEnabled) {
                Log.d("gps", "gpsenabled");
                if (location == null) {
                    Log.d("gps", "location is null");
                    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    if (locationManager != null) {
                        Log.d("gps", "locationManager is not null");
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            Log.d("gps", "location is not null");
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                            Log.d("gps", "lat: " + latitude + ", lon: " + longitude);
                        }
                    }
                }
            }
            if (isNetworkEnabled) {
                Log.d("gps", "networkenabled");
                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                if (locationManager != null) {
                    Log.d("gps", "locationManager is not null");
                    location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        Log.d("gps", "location is not null");
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                        Log.d("gps", "lat: " + latitude + ", lon: " + longitude);
                    }
                }
            }
            //
            LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

            Criteria criteria = new Criteria();
            String bestProvider = lm.getBestProvider(criteria, false);
            Log.d("gps", "bestProvider: " + bestProvider);
            Location location = lm.getLastKnownLocation(bestProvider);
            Log.d("gps", "lat: " + location.getLatitude() + ", lon: " + location.getLongitude());
            //
        }
    } catch (Exception e) {

    }
    return location;
}

public void stopUsingGPS() {
    if (locationManager != null) {
        locationManager.removeUpdates(GPSTracker.this);
    }
}

public double getLatitude() {
    if (location != null) {
        latitude = location.getLatitude();
    }
    return latitude;
}

public double getLongitude() {
    if (location != null) {
        latitude = location.getLongitude();
    }
    return longitude;
}

public boolean canGetLocation() {
    return this.canGetLocation;
}

public void showSettingsAlert() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
    alertDialog.setTitle("GPS is settings");
    alertDialog.setMessage("GPS is not enabled. Do you want to go to setttings menu ?");
    alertDialog.setPositiveButton("Setting", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            context.startActivity(intent);
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.cancel();
        }
    });
    alertDialog.show();
}

@Override
public void onLocationChanged(Location location) {
    this.location = location;
    latitude = getLatitude();
    longitude = getLongitude();

    Log.d("gps", "onLocationChanged");
}

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

}

@Override
public void onProviderEnabled(String provider) {

}

@Override
public void onProviderDisabled(String provider) {

}

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