Get a firestore document id from autocompletetextv

My problem is very simple and clear. I already did fetch data from the firestore cloud-firestore database, it is being suggested in AutoCompleteTextView very well, and clickable. However, I want to get the firebase cloud-firestore document id of the selected item. Tested with toasting it

private var autoComplete: ArrayAdapter<String>? = null
private var itemId: String? = null

override fun onCreate(savedInstanceState: Bundle?) {
    readData(object: MyCallback {
        override fun onCallback(value: ArrayAdapter<String>) {
            Log.d(TAG, "The list has: " + value.count.toString() + " items.")
        }
    })

    textCurrentSearch.setAdapter(autoComplete)

    textCurrentSearch.onItemClickListener = OnItemClickListener { parent, view, position, id ->

        showShortToast(this@NewOrderActivity, "Item on cloud-firestore id: " + itemId!! + "Item on ArrayAdapter id: " + id)
    }
}

fun showShortToast(context: Context, message: String) {
    Toast.makeText(context, message, Toast.LENGTH_SHORT).show()
}

private fun readData(myCallback : MyCallback) {
    Log.d(TAG, "Before attaching the listener!")

    mFirebaseFirestore.collection("tblProductItems").get().addOnCompleteListener { task ->
        if (task.isSuccessful) {
            Log.d("TAG", "Inside onComplete function!")
            for (document in task.result!!) {
                val name = document.data["name"].toString()

                itemId = document.id

                autoComplete?.add(name)
            }

            myCallback.onCallback(autoComplete!!)

        } else showShortToast(this@NewOrderActivity, task.exception!!.toString())
    }.addOnSuccessListener {
        showShortToast(this@NewOrderActivity, "")
    }

    Log.d(TAG, "After attaching the listener!")
}

interface MyCallback {
    fun onCallback(value: ArrayAdapter<String>)
}

I tried with the

itemId = suggestSnapshot.id

but it does not get me the id of the selected product item doument. Kindly help with anything constructive, thank you.

To solve this, please move the lines where you are setting the addapter and you are attaching the lister right inside the callback like so:

override fun onCreate(savedInstanceState: Bundle?) {
    mFirebaseFirestore.collection("tblProductItems").addSnapshotListener { querySnapshot, exception ->
        if (exception != null) {
            showShortToast(this@NewOrderActivity, exception.toString())
        }

        for (suggestSnapshot in querySnapshot!!.documents) {
            val suggestion = suggestSnapshot.getString("name")

            itemId = suggestSnapshot.id

            //Add the retrieved string to the list
            autoComplete?.add(suggestion)
        }
        textCurrentSearch.setAdapter(autoComplete)
        textCurrentSearch.onItemClickListener = OnItemClickListener { parent, view, position, id ->
            showShortToast(this@NewOrderActivity, "Item on cloud-firestore id: " + itemId!! + "Item on ArrayAdapter id: " + id)
        }
    }
}

Firebase API is asynchronous meaning that the data is available only if you wait for it. For more informations, I recommend you also see my answer from this post.