[Question]: Possibility of using Android `AltitudeConverter` for WGS84 -> MSL

[zmuranaka]

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• I have carefully read the documentation.

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Your question

When using Geolocator.getCurrentPosition on Android, we know that even if you have useMSLAltitude set to true from the AndroidSettings, it has no effect, as stated in the Dartdoc here:

flutter-geolocator/geolocator_android/lib/src/types/android_settings.dart

Lines 68 to 69 in 756b8d8

	/// This property only works with position stream updates and has no effect when getting the
	/// current position or last known position.

However, android.location.altitude supports an AltitudeConverter class, which does the following:

Converts altitudes reported above the World Geodetic System 1984 (WGS84) reference ellipsoid into ones above Mean Sea Level.

Is there a way AltitudeConverter could be used by getCurrentPosition to convert locations with WGS84 altitude into MSL? I understand that when getCurrentPosition is called, it calls onGetCurrentPosition, which in turn starts position updates here:

flutter-geolocator/geolocator_android/android/src/main/java/com/baseflow/geolocator/MethodCallHandlerImpl.java

Line 241 in 756b8d8

geolocationManager.startPositionUpdates(

My idea was something like the following (although I am no Java expert, so take with a grain of salt):

geolocationManager.startPositionUpdates(
    locationClient,
    activity,
    (Location location) -> {
      if (replySubmitted[0]) {
        return;
      }

      replySubmitted[0] = true;
      geolocationManager.stopPositionUpdates(locationClient);
      pendingCurrentPositionLocationClients.remove(requestId);
      // Start added code
      boolean useAltitudeConverter = (boolean) map.get("useMSLAltitude");
      if (useAltitudeConverter && Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
        AltitudeConverter altitudeConverter = new AltitudeConverter();
        boolean mslAdded = altitudeConverter.tryAddMslAltitudeToLocation(location);
        if (!mslAdded) {
          new Thread(() -> {
            try {
              altitudeConverter.addMslAltitudeToLocation(context, location);
            } catch (IOException e) {
              Log.e(TAG, "AltitudeConverter IOException: " + e.getMessage());
            }
          }).start();
        }
      }
      // End added code
      result.success(LocationMapper.toHashMap(location));
    },
    (ErrorCodes errorCode) -> {
      if (replySubmitted[0]) {
        return;
      }

      replySubmitted[0] = true;
      geolocationManager.stopPositionUpdates(locationClient);
      pendingCurrentPositionLocationClients.remove(requestId);
      result.error(errorCode.toString(), errorCode.toDescription(), null);
    });

In my brief testing of this it did not work. Is there any chance this could be made to work?

Version

14.0.2