Can't recevie documentID from Firebase Firestore in Kotlin

Question

Hi i am trying to recevie documentID from Firebase Firestore to use for deleting item from recyclerView. I tried to add it to my document first, then i will retrieve it and user could delete whichever item that user wants within docID. Firstly equalized the documentId variable to an empty string then added a snapshotListener in addData function, with for loop i equalized every document.id value to my empty documentID.

Problem is occuring there: documentId variable returns empty value everytime. Pls help.

Sorry for any infancy.

Thanks in advance.

---

addData Function:

fun addData(view: View) {
  var chosenPair=ozelSharedPreferences.clickiAl().toString()
    val currentU = Firebase.auth.currentUser
    val dbCollection = currentU?.let {
        it.email.toString()
    }
    var documentId= ""
    val docRef = database.collection(dbCollection!!).document("Specified").collection("Pairs")
        .document(chosenPair).collection("Analysis").orderBy("time")
    docRef.addSnapshotListener { value, error ->
        if (value != null && !value.isEmpty) {

            val documents = value.documents

            for (document in documents) {
                documentId=document.id

            }
        }
    }

    val time= com.google.firebase.Timestamp.now()

    val rr=rrText.text.toString()
    var doubleRR=rr.toDoubleOrNull()
    if (doubleRR==null) {
        doubleRR=0.0
    }
    val analyzeDTO = AnalyzeDTO(
        chartImage.text.toString(),
        doubleRR,
        reasonForText.text.toString(),
        resultAddingText.text.toString(),
        conceptText.text.toString(),
        documentId,
        time
    )
    viewModel.save(analyzeDTO)

    val intent = Intent(this, PairDetailActivity::class.java)
    startActivity(intent)
    finish()

}

---

Retrieving Data Function:

fun retrieveData() {

    var chosenPair=ozelSharedPreferences.clickiAl().toString()
    val currentU = Firebase.auth.currentUser
    val dbCollection = currentU?.let {
        it.email.toString()
    }


    val docRef = database.collection(dbCollection!!).document("Specified").collection("Pairs")
        .document(chosenPair).collection("Analysis").orderBy("time")

    docRef.addSnapshotListener { value, error ->
        if (value != null && !value.isEmpty) {

            val documents = value.documents

            for (document in documents) {

                var docID= document.get("docID") as String

                val url = document.get("tradingViewUrl") as String?
                val rr = document.get("rrRatio") as Double?
                val reason = document.get("reason") as String?
                val result = document.get("result") as String?
                val concept= document.get("concept") as String?
                val time= document.get("time") as Timestamp

                val downloadedAnalyze = AnalyzeDTO(url, rr, reason, result,concept, docID,time)
                var analyzeList = arrayListOf(downloadedAnalyze)
                list.value=analyzeList
            }
        } else if (error!= null) {
            Toast.makeText(getApplication(),error.localizedMessage,Toast.LENGTH_LONG)
        } else {
             Toast.makeText(getApplication(),"Unknown Error", Toast.LENGTH_SHORT)
        }
    }
}