Retrieving data from Firebase (Realtime Database) into a list (Kotlin) - list

Question

The RealtimeDatabase structure in Firebase
I want to go over the entire users in "mifkada" and to add them into a list as a BlogPost object:
class BlogPost (
var namerv: String,
var gafrv: String,
var placerv: String,
var phonerv: String,
var notesrv: String
) {
constructor() : this("", "", "", "", "") {}
}
I tried to do it with a for loop but it doesn't work the way I wrote it
class DataSource{
companion object{
fun createDataSet(): ArrayList<BlogPost>{
var databaseMifkada = FirebaseDatabase.getInstance().getReference("mifkada")
val list = ArrayList<BlogPost>()
val postListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
if(dataSnapshot!!.exists()){
list.clear()
for (e in dataSnapshot.children){
val post = e.getValue(BlogPost::class.java)
list.add(post!!)
}
}
}
override fun onCancelled(databaseError: DatabaseError) {
// Getting Post failed, log a message
Log.w(TAG, "loadPost:onCancelled", databaseError.toException())
}
}
databaseMifkada.addValueEventListener(postListener)
return list
}
}
}

Answer 1

The values of your constructor does not match the names of your database values
class BlogPost (
var namerv: String,
var gafrv: String,
var placerv: String,
var phonerv: String,
var notesrv: String
) {
constructor() : this("", "", "", "", "") {}
}
Should be
class BlogPost (
var name: String,
var gaf: String,
var place: String,
var phone: String,
var notes: String
) {
constructor() : this("", "", "", "", "") {}
}
You need to have the same name because when you do
val post = e.getValue(BlogPost::class.java)
it will look for those field names under the reference, and if it can't be reached, you can't get those values