可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):
问题:
I am trying to get a device's location information using GPS, but for some reason one of the two coordinates is missing sometimes.
This is the code:
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER); double longitude = location.getLongitude(); double latitude = location.getLatitude(); Log.d("LOCATION1", "Longitude: " + longitude); Log.d("LOCATION2", "Latitude: " + latitude);
Sometimes I do get both coordinates, but not always, which makes me think about some kind of delay somewhere. Is there a way to find out why a GPS coordinate is missing when this happens?
回答1:
Because the GPS isn't always on. getLastKnownLocation will return a location if it knows one and if it isn't too stale. Since nothing else was using the GPS, it doesn't know one. If you need a location, either requestLocationUpdates or requestSingleUpdate, which will turn on the GPS and get a new location.
回答2:
Criteria criteria = new Criteria(); LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); // mMap.addMarker(new MarkerOptions().position(sydney2).title("fi")); if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } locationManager.requestLocationUpdates(locationManager.getBestProvider(criteria, true), 2000, 0, new android.location.LocationListener() { @Override public void onLocationChanged(Location location) { // }
in onLocationChanged method you can use location.getLatitude & location.getLongitude
