在地图上同时显示多个用户的位置（Kotlin、Firebase 实时数据库）

Question

这个问题反映了上一个问题：Show multiple registered user`s location on the same map (Android Studio, Firebase, Kotlin)

我的主要问题是我在 Android Studio 中创建了一个聊天应用程序，并且还使用 Google Api 添加了一个地图活动。我正在使用 Firebase 实时数据库，这就是我的树目前的样子：

我希望“用户位置”出现在每个注册用户的下方，因此所有注册用户的位置都会作为标记出现在我的 Google 地图上。

这是我的 MapsActivity：

class MapsActivity : AppCompatActivity(), OnMapReadyCallback {

    companion object {
        var currentUser: User? = null
        val TAG = "MapsActivity"
    }



    private lateinit var map: GoogleMap
    private val LOCATION_PERMISSION_REQUEST = 1
    private lateinit var fusedLocationClient: FusedLocationProviderClient
    private lateinit var locationRequest: LocationRequest
    private lateinit var locationCallback: LocationCallback


    private fun getLocationAccess() {
        if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            map.isMyLocationEnabled = true
            getLocationUpdates()
            startLocationUpdates()
        }
        else
            ActivityCompat.requestPermissions(this, arrayOf(android.Manifest.permission.ACCESS_FINE_LOCATION), LOCATION_PERMISSION_REQUEST)


    }



    private fun getLocationUpdates() {
        locationRequest = LocationRequest()
        locationRequest.interval = 30000
        locationRequest.fastestInterval = 20000
        locationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY

        locationCallback = object : LocationCallback() {
            override fun onLocationResult(locationResult: LocationResult) {
                if (locationResult.locations.isNotEmpty()) {
                    val location = locationResult.lastLocation




//                    val uid = FirebaseAuth.getInstance().currentUser?.uid
//                    val rootRef =  FirebaseFirestore.getInstance()
//                    val usersRef = rootRef.collection("users")
//                    val uidRef = uid?.let { usersRef.document(it) }
//                    if (uidRef != null) {
//                        uidRef.get()
//                                .addOnSuccessListener { document ->
//                                    if (document != null) {
//                                        val latitude = document.getDouble("latitude")
//                                        val longitude = document.getDouble("longitude")
//                                        Log.d(TAG, ", " + location.latitude + location.longitude)
//                                    } else {
//                                        Log.d(TAG, "No such document")
//                                    }
//                                }
//                                .addOnFailureListener { exception ->
//                                    Log.d(TAG, "get failed with ", exception)
//                                }
//                    }


                    lateinit var databaseRef: DatabaseReference
                    databaseRef = Firebase.database.reference
                    val locationlogging = LocationLogging(location.latitude, location.longitude)
                    databaseRef.child("/userlocation").setValue(locationlogging)

                        .addOnSuccessListener {
                            Toast.makeText(applicationContext, "Locations written into the database", Toast.LENGTH_LONG).show()
                        }
                        .addOnFailureListener {
                            Toast.makeText(applicationContext, "Error occured while writing your location to the database", Toast.LENGTH_LONG).show()
                        }

                }

            }
        }
    }




    @SuppressLint("MissingPermission")
    private fun startLocationUpdates() {
        fusedLocationClient.requestLocationUpdates(locationRequest,locationCallback, null)
    }


    @SuppressLint("MissingPermission")
    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
        if (requestCode == LOCATION_PERMISSION_REQUEST) {
            if (grantResults.contains(PackageManager.PERMISSION_GRANTED)) {
                map.isMyLocationEnabled = true
            } else { Toast.makeText(this, "User has not granted location access permission", Toast.LENGTH_LONG).show()
                finish()
            }
        }
    }


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_maps)

          
        

        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        val mapFragment = supportFragmentManager
            .findFragmentById(R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
    }


    override fun onMapReady(googleMap: GoogleMap) {
        map = googleMap
        getLocationAccess()
    }




    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        menuInflater.inflate(R.menu.nav_menu_map, menu)
        return super.onCreateOptionsMenu(menu)
    }

我注释掉了一些代码，因为我无法正确实现它。当我运行代码时，经纬度出现在我的 Logcat 中，但在我的实时数据库中，它清除了 /users 下的所有数据，并被经纬度替换。

这是我的位置记录：

import com.google.firebase.database.IgnoreExtraProperties

@IgnoreExtraProperties

data class LocationLogging(
    var Latitude: Double? = 0.0,
    var Longitude: Double? = 0.0
)

我正在寻找一种简单的方法，将坐标放入我的每个注册用户下的 Firebase 实时数据库中，并同时在地图上显示所有位置。

Answer 1

您可以通过firebase auth SDK获取当前用户并更改保存数据的路径以将其保存在用户路径下。您需要更改这部分代码：

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
 lateinit var databaseRef: DatabaseReference
                    databaseRef = Firebase.database.reference
                    val locationlogging = LocationLogging(location.latitude, location.longitude)
                    databaseRef.child("users").child(user.getUid()).child("userlocation").setValue(locationlogging)

                        .addOnSuccessListener {
                            Toast.makeText(applicationContext, "Locations written into the database", Toast.LENGTH_LONG).show()
                        }
                        .addOnFailureListener {
                            Toast.makeText(applicationContext, "Error occured while writing your location to the database", Toast.LENGTH_LONG).show()
                        }