如何从 Firestore 检索文档并将其分配给变量？ [安卓] [科特林]

Question

So I want to retrieve a particular Document from a Collection in Firestore and assign the document to a variable so that i can use it in other activity.

Collection contains Users as documents.

**FirebaseFirestore.getInstance().collection(Users).document(getCurrentUserID()).get() ....**

Model class: USER

fun getCurrentUserID(): String {
    var currentUser = FirebaseAuth.getInstance().currentUser
    var currentUserID = ""
    if (currentUser != null) {
        currentUserID = currentUser.uid
    }
    return currentUserID
}

Answer 1

You can get your user with using code below, then you can do whatever you want with it.

       FirebaseFirestore.getInstance()
            .collection("Users")
            .document(getCurrentUserID())
            .get()
            .addOnSuccessListener { document ->
                val user = document.toObject(USER::class.java)!!
                // Now we stored information to user variable.
                // You can use it by simply calling user.name etc.
            }
            .addOnFailureListener { e ->
                Log.e(
                    this.javaClass.simpleName,
                        "Error while getting user details.",
                        e
                )
            }