Styjun

I am trying to grab data(lat and long) from Firebase and place it as markers to populate my Google map. I am using Kotlin.

jsonFirebaseData

I have tried the official Firebase documentation to read data, as well as tried:

http://myfirebasemaps.ga/

Also tried:

Retrieve location from Firebase and put marker on google map api for android application

private lateinit var mCompanies: DatabaseReference

onCreate section:

mCompanies = FirebaseDatabase.getInstance().reference

onMapReady section:

 fun loadMarkersFromDB() 
 mCompanies = FirebaseDatabase.getInstance().getReference().child("results")
 mCompanies.addListenerForSingleValueEvent(object : ValueEventListener 

 override fun onDataChange(dataSnapshot: DataSnapshot) 
 for (s in dataSnapshot.children) 
 var company = dataSnapshot.getValue(Company::class.java)
 var location = LatLng(company!!.latitude, company.longitude!!)
 mMap.addMarker(MarkerOptions().position(location).title(company!!.name).snippet(company!!.city))
 .setIcon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_YELLOW))
 
 

 override fun onCancelled(databaseError: DatabaseError) 
 Log.w("MapsActivity", databaseError.toException())
 
 )
 

Also I have a data class:

data class Company(
 var city: String,
 var latitude: Double,
 var longitude: Double,
 var name: String
) 
 constructor() : this("", 0.0, 0.0, "")

Nothing happens. App does not crash, but no markers gets added from my firebase.

EDIT

I created a private function:

 private fun loadMarkersFromDB() 
 mCompanies = FirebaseDatabase.getInstance().reference
 mCompanies.addListenerForSingleValueEvent(object : ValueEventListener 
 override fun onDataChange(dataSnapshot: DataSnapshot) 
 if (dataSnapshot.exists()) 
 for (s in dataSnapshot.children) 
 var company = dataSnapshot.getValue(Company::class.java)
 var location = LatLng(company!!.latitude, company.longitude!!)
 mMap.addMarker(MarkerOptions().position(location).title(company!!.name).snippet(company!!.city))
 .setIcon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_YELLOW))
 Log.d("onDataChange", company.toString())
 
 
 

 override fun onCancelled(databaseError: DatabaseError) 
 Log.w("MapsActivity", databaseError.toException())
 
 )
 

Then I call the function in onMapReady after the map has been created.

Log.d("onDataChange", company.toString())

displays this on Logcat:

D/onDataChange: Company(city=, latitude=0.0, longitude=0.0, name=)

When I change it to company!!.city nothing shows up.

You aren't getting anything because your reference points to the root node and not to the results node. To sovle this, simply change the following line of code:

mCompanies.addListenerForSingleValueEvent(/* ... */)

to

mCompanies.child("data").child("results").addListenerForSingleValueEvent(/* ... */)