Use altitude above mean sea level

app/src/main/kotlin/com/sanmer/geomag/app/utils/LocationManagerUtils.kt

@@ -5,6 +5,7 @@ import android.annotation.SuppressLint
 import android.content.Context
 import android.content.pm.PackageManager
 import android.location.LocationManager
+import android.location.OnNmeaMessageListener
 import android.os.Handler
 import android.os.Looper
 import androidx.compose.runtime.Composable
@@ -85,6 +86,7 @@ object LocationManagerUtils {
  close()
  }
 
+ val locationManager = context.locationManager
  val listener = LocationListenerCompat {
  trySend(it)
  }
@@ -97,21 +99,22 @@ object LocationManagerUtils {
  runCatching {
  Timber.d("requestLocationUpdates")
  LocationManagerCompat.requestLocationUpdates(
- context.locationManager,
+ locationManager,
  LocationManager.GPS_PROVIDER,
  locationRequest,
  listener,
  Looper.getMainLooper()
  )
  }.onFailure {
- Timber.e(it, "locationUpdates")
+ Timber.e(it, "getLocationAsFlow")
  close(it)
  }
 
  awaitClose {
  Timber.d("removeUpdates")
- LocationManagerCompat.removeUpdates(context.locationManager, listener)
+ LocationManagerCompat.removeUpdates(locationManager, listener)
  }
+
  }.flowOn(Dispatchers.Default)
 
  @SuppressLint("MissingPermission")
@@ -120,6 +123,7 @@ object LocationManagerUtils {
  close()
  }
 
+ val locationManager = context.locationManager
  val callback = object : GnssStatusCompat.Callback() {
  override fun onSatelliteStatusChanged(status: GnssStatusCompat) {
  trySend(status)
@@ -129,18 +133,59 @@ object LocationManagerUtils {
  runCatching {
  Timber.d("registerGnssStatusCallback")
  LocationManagerCompat.registerGnssStatusCallback(
- context.locationManager,
+ locationManager,
  callback,
  Handler(Looper.getMainLooper())
  )
  }.onFailure {
- Timber.e(it, "gnssStatusUpdates")
+ Timber.e(it, "getGnssStatusAsFlow")
  close(it)
  }
 
  awaitClose {
  Timber.d("unregisterGnssStatusCallback")
- LocationManagerCompat.unregisterGnssStatusCallback(context.locationManager, callback)
+ LocationManagerCompat.unregisterGnssStatusCallback(locationManager, callback)
  }
- }
+
+ }.flowOn(Dispatchers.Default)
+
+ @SuppressLint("MissingPermission")
+ fun getAltitudeMeanSeaLevel(context: Context) = callbackFlow {
+ if (!(context.hasPermissions() && isEnable)) {
+ close()
+ }
+
+ val locationManager = context.locationManager
+ val listener = OnNmeaMessageListener { message, _ ->
+ if (NMEA_KEYS.any { message.startsWith(it) }) {
+ val mslAltitudeMeters = message.split(",")
+ .getOrNull(MSL_ALTITUDE_INDEX)
+ ?.toDoubleOrNull()
+
+ if (mslAltitudeMeters != null) {
+ trySend(mslAltitudeMeters)
+ }
+ }
+ }
+
+ runCatching {
+ Timber.d("addNmeaListener")
+ locationManager.addNmeaListener(
+ listener,
+ Handler(Looper.getMainLooper())
+ )
+ }.onFailure {
+ Timber.e(it, "getNmeaAsFlow")
+ close(it)
+ }
+
+ awaitClose {
+ Timber.d("removeNmeaListener")
+ locationManager.removeNmeaListener(listener)
+ }
+
+ }.flowOn(Dispatchers.Default)
+
+ private const val MSL_ALTITUDE_INDEX = 9
+ private val NMEA_KEYS = listOf("\$GPGGA", "\$GNGNS", "\$GNGGA")
 }

app/src/main/kotlin/com/sanmer/geomag/app/utils/OsUtils.kt

@@ -4,6 +4,9 @@ import android.os.Build
 import androidx.annotation.ChecksSdkIntAtLeast
 
 object OsUtils {
+ @get:ChecksSdkIntAtLeast(api = Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+ val atLeastU get() = Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE
+
  @get:ChecksSdkIntAtLeast(api = Build.VERSION_CODES.TIRAMISU)
  val atLeastT get() = Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU
 

app/src/main/kotlin/com/sanmer/geomag/service/LocationService.kt

@@ -14,7 +14,9 @@ import androidx.lifecycle.LifecycleService
 import androidx.lifecycle.flowWithLifecycle
 import androidx.lifecycle.lifecycleScope
 import com.sanmer.geomag.app.utils.LocationManagerUtils
+import com.sanmer.geomag.app.utils.OsUtils
 import com.sanmer.geomag.model.gnss.Satellite
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 
@@ -25,17 +27,26 @@ class LocationService : LifecycleService() {
 
  LocationManagerUtils.getLocationAsFlow(this)
  .flowWithLifecycle(lifecycle, Lifecycle.State.STARTED)
- .onEach {
- location = it
- }
- .launchIn(lifecycleScope)
+ .combine(
+ LocationManagerUtils.getAltitudeMeanSeaLevel(this)
+ ) { mLocation, mMslAltitudeMeters ->
+
+ mLocation.altitude = if (OsUtils.atLeastU && mLocation.hasMslAltitude()) {
+ mLocation.mslAltitudeMeters
+ } else {
+ mMslAltitudeMeters
+ }
+
+ location = mLocation
+
+ }.launchIn(lifecycleScope)
 
  LocationManagerUtils.getGnssStatusAsFlow(this)
  .flowWithLifecycle(lifecycle, Lifecycle.State.STARTED)
  .onEach {
  gnssStatusOrNull = it
- }
- .launchIn(lifecycleScope)
+
+ }.launchIn(lifecycleScope)
  }
 
  override fun onDestroy() {