How to retrieve nested object from a document and display it in FirestoreRecyclerOptions?

Question

I have this data structure in Firestore as shown in the image.

I am using FirestoreRecyclerOptions to display user`s addresses. I am storing the address as POJO (UserAddressModel.java), I do not know if it the best practice or not to store it that way or not but that how I did it.

UserInformationsModel.java

   public class UserInformationsModel {

private String email, username, name ;
private UserAddressModel userAddress;   
private String phoneNumber;
private String photo;
private String photoUrl;



public UserInformationsModel() {
}
}

UserAddressModel.java

 public class UserAddressModel {

private String fullName, streetAddressOne, streetAddressTwo, city, state, country;
private String zipCode;

public UserAddressModel() {
}



public UserAddressModel(  String streetAddressOne, String city, String state, String country, String zipCode) {

    this.streetAddressOne = streetAddressOne;
    this.city = city;
    this.state = state;
    this.country = country;
    this.zipCode = zipCode;
}
public String getFullName() {
    return fullName;
}

public String getStreetAddressOne() {
    return streetAddressOne;
}

public String getStreetAddressTwo() {
    return streetAddressTwo;
}

public String getCity() {
    return city;
}

public String getState() {
    return state;
}

public String getCountry() {
    return country;
}

public String getZipCode() {
    return zipCode;
}

I have already created the AdapterAddress class that extended FirestoreRecyclerAdapter and it`s layout.

My question is how to display address1 and address2 in my recyclerview ? Because I am notice that setQuery method require a query but i do not know how to get the addresses

Query query = coll_ref.orderBy("?????");

  FirestoreRecyclerOptions<UserAddressModel> options = new   FirestoreRecyclerOptions.Builder<UserAddressModel>()
            .setQuery(query, UserAddressModel.class)
            .build();
     adapterAddress = new AdapterAddress(options);

Answer 1

There is no way you can get those addresses using a query. FirestoreRecyclerOptions object require a Query or a CollectionReference to be passed to the setQuery() method when you need to get all documents within a collection or when you need to filter them.

What you need to do is to get a reference on the user document and make a get() call:

String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionReference usersRef = rootRef.collection("users");
usersRef.document(uid).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            DocumentSnapshot document = task.getResult();
            if (document.exists()) {
                Map<String, Object> map = document.getData();
            }
        }
    }
});

See, document.getData() returns a map. Simply ieterate through the map and get the addresses.