在某些Android手机中无法准确定位

Question

I have used below code. It work fine but in some devices like Redme,Asus not getting accurate location.It shown me too far from my current location aprox 20 km away.Not getting where is problem somebody have idea please share there ideas.Thanks in advance.

public class Currentlocation 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
public boolean canGetLocation = false;

Location location; // location
double latitude; // latitude
double longitude; // longitude

// 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;

SetOnLocationFoundListner OLF;

public interface SetOnLocationFoundListner {
    public void onLocationFound(Location location, boolean getLocRegularly, GoogleMap gmap);
}

public Currentlocation(Context context) {
    this.mContext = context;
    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();
                    }
                }
            }
            // 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();
                        }
                    }
                }
            }
        }

    } 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(Currentlocation.this);
    }
}

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

    // return latitude
    return latitude;
}

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

    // return longitude
    return longitude;
}

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

@Override
public void onLocationChanged(Location location) {
    // TODO Auto-generated method stub

}

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

}

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

}

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

}

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

/**
 * Function to show settings alert dialog On pressing Settings button will
 * lauch Settings Options
 */

}

Answer 1

You can not expect the phone neither to always have a valid "last known location" nor to define its location in microseconds.

You first call requestLocationUpdates() and instantly after that getLastKnownLocation() . There's no time for the phone to determine/update the "last known location". Besides now you always call requestLocationUpdates() again and again when you call getLocation() . Just call it once when you want to start receiving location updates.

Just subscribe to receive location updates once and always get the latest location in the callback that happens with a small delay. You already have the empty onLocationChanged() method. That is the callback method. Just make that to handle the location updates.

You can of course call removeUpdates() or removeLocationUpdates() once you have received the fresh and up-to-date location in the onLocationChanged() callback if you don't want to receive any further updates.

Some useful Stackoverflow discussions:

How to get location that isn't out of date?

Android: getLastKnownLocation out-of-date - how to force location refresh?

Android - Reliably getting the current location