Kotlin:: Reading data from Firebase

In order to read your data from Firebase with Kotlin you need to go through the usual rigmarole of setting up Firebase and Kotlin in Android Studio - I'm not even going near the Android Studio 3 Preview because it's as buggy as a a nest of fly lavae.

Ok here we go:

1. Declare the DatabaseReference object in your class, I use the lateinit modifier because it allows me declare the object without having to initialize it immediately. I can initialize it later at my leisure:

lateinit var databaseRef: databaseReference

2 I initialize it within my onCreate like so:

databaseRef = FirebaseDatabase.getInstance().getReference()
Please make sure you import 
import com.google.firebase.database.*

3 I call a method getGreeting()
 In this method I call the entry "greeting" in my Firebase app account. greeting is just a name value entry with a string as the value. To listen for the response of my call, I have the ValueEventListener added to the reference call like so:

      override fun onDataChange(snapshot: DataSnapshot){\
          println("TestBed: ${snapshot.value}")

That's it really, the code below shows you the complete business

import com.google.firebase.database.*

class TestBedScrollingActivity : AppCompatActivity() {
    lateinit var databaseRef: DatabaseReference    override fun onCreate(savedInstanceState: Bundle?) {
        val toolbar = findViewById(R.id.toolbar) as Toolbar        setSupportActionBar(toolbar)

        val fab = findViewById(R.id.fab) as FloatingActionButton        fab.setOnClickListener { view ->            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show()
        }        databaseRef = FirebaseDatabase.getInstance().getReference()
// [  Begin get greeting form Firebase  ]    fun getGreeting(){
    println("--------- start greeting ----------")
        databaseRef.child("greeting").addValueEventListener(object : ValueEventListener {

            override fun onDataChange(snapshot: DataSnapshot) {
                println("TestBed: ${snapshot.value}")

            override fun onCancelled(error: DatabaseError) {}
//   [ End get greeting from Firebase ]


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