Failure to read nested child node in firebase realtime database in kotlin

Question

I want to read the values in location and store it in an array. But when I run the code I get empty values in the arrays. Here I am trying to read the values in the -MgvP468FQ-jclZWHC5Snode. How to read the values and store it in the array. I am not getting any values in lat1, long1.

var ref1= FirebaseDatabase.getInstance().getReference("location").child("oBwEgUfhMbQoPPovRXkgWJcHz6B2")

ref1.addValueEventListener(object : ValueEventListener{
    override fun onDataChange(p0: DataSnapshot) {
        if (p0.exists()){
            for (idsnapshot in p0.children){
                for (locsnapshot in idsnapshot.child("-MgvP468FQ-jclZWHC5S").children){

                    val lat1 = locsnapshot.child("latitude").value as Double
                    val long1 = locsnapshot.child("longitude").value as Double

                    Log.d("TAG", "$locsnapshot")

                    Toast.makeText(requireContext() ,"success$locsnapshot", Toast.LENGTH_SHORT).show()


                    Toast.makeText(requireContext() ,"success$lat1,$long1", Toast.LENGTH_SHORT).show()


                    lat = lat1.toDouble()
                    val LatLng = LatLng(lat1, long1)
                    list.add(LatLng)


                }
            }
        }

    }

    override fun onCancelled(p0: DatabaseError) {

    }

})

Answer 1

As far as I can see you have a few mistakes in the handling of the data.

This should be closer:

ref1.addValueEventListener(object : ValueEventListener{
  override fun onDataChange(snapshot: DataSnapshot) {
    if (snapshot.exists()){
      for (childsnapshot in snapshot.child("-MgvP468FQ-jclZWHC5S").children){  // 👈 children location8 and location9
        for (locsnapshot in childsnapshot.children){ // 👈 children 0..4
          val lat1 = locsnapshot.child("latitude").value as Double
          val long1 = locsnapshot.child("longitude").value as Double
          ...
        }
      }
    }