[英]Google maps GPS: longitude and latitude returns zero
我需要从Main类获取位置或纬度经度,但如果我获得位置,则返回null;如果我获得纬度和经度,则返回0.0,如下面的代码所示。 尝试最小化代码并使其尽可能清晰。
这是我需要从主要班级获得位置的服务班级
public void onLocationChanged(Location location)
{
Log.e(TAG, "onLocationChanged: " + location);
mLastLocation.set(location);
if(MainActivity.isMarkerDragged()) {
Location markerLocation = new Location(LocationManager.GPS_PROVIDER);
markerLocation.setLatitude(MainActivity.getMarkerLat());
markerLocation.setLongitude(MainActivity.getMarkerLon());
Toast.makeText(mContext, MainActivity.getMarkerLon() + " = " + MainActivity.getMarkerLat(), Toast.LENGTH_SHORT).show();
// Current location
distance = location.distanceTo(markerLocation);
Toast.makeText(mContext, "marker dragged " + distance, Toast.LENGTH_SHORT).show();
}
}
在onLocationChanged方法上,我正在获得此经度和纬度
endPoint.setTitle(endPoint.getPosition().longitude + ", " + endPoint.getPosition().latitude);
这按计划工作,但是当我获得服务时,它返回0.0(吸)
public static Marker endPoint;
public static boolean markerDragged = true;
public static boolean serviceStarted = false;
private static double markerLat;
private static double markerLon;
/**
* Gets the current location of the device, and positions the map's camera.
*/
private void getDeviceLocation() {
/*
* Request location permission, so that we can get the location of the
* device. The result of the permission request is handled by a callback,
* onRequestPermissionsResult.
*/
if (ContextCompat.checkSelfPermission(this.getApplicationContext(),
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
mLocationPermissionGranted = true;
} else {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
}
/*
* Get the best and most recent location of the device, which may be null in rare
* cases when a location is not available.
*/
if (mLocationPermissionGranted) {
mLastKnownLocation = LocationServices.FusedLocationApi
.getLastLocation(mGoogleApiClient);
}
// Set the map's camera position to the current location of the device.
if (mCameraPosition != null) {
mMap.moveCamera(CameraUpdateFactory.newCameraPosition(mCameraPosition));
} else if (mLastKnownLocation != null) {
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(mLastKnownLocation.getLatitude(),
mLastKnownLocation.getLongitude()), DEFAULT_ZOOM));
// Adding a marker
endPoint = mMap.addMarker(new MarkerOptions()
.draggable(true)
.position(new LatLng(mLastKnownLocation.getLatitude(),
mLastKnownLocation.getLongitude())));
endPoint.setTitle(getString(R.string.drag));
} else {
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(mDefaultLocation, DEFAULT_ZOOM));
mMap.getUiSettings().setMyLocationButtonEnabled(false);
}
}
@Override
public void onMarkerDragEnd(Marker marker) {
if(!serviceStarted) {
startService(new Intent(this, LocationService.class));
}
}
@Override
public void onMarkerDragStart(Marker marker) {
setMarkerDragged(true);
markerLat = marker.getPosition().latitude;
markerLon = marker.getPosition().longitude;
endPoint.setTitle(endPoint.getPosition().longitude + ", " + endPoint.getPosition().latitude);
}
public static double getMarkerLon(){
return markerLon;
}
public static double getMarkerLat(){
return markerLat;
}
找到解决方案:在主类上:
Intent intent = new Intent(this, LocationService.class);
intent.putExtra("latitude", endPoint.getPosition().latitude);
intent.putExtra("longitude", endPoint.getPosition().longitude);
startService(intent);
和服务:
public int onStartCommand(Intent intent, int flags, int startId)
{
Log.e(TAG, "onStartCommand");
super.onStartCommand(intent, flags, startId);
markerLat = (Double) intent.getExtras().get("latitude");
markerLon = (Double) intent.getExtras().get("longitude");
return START_STICKY;
}
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