FirestoreRecyclerOptions

FirestoreRecyclerOptions is a utility class provided by FirebaseUI library for Android to simplify the integration of Firestore Query with RecyclerView.

FirestoreRecyclerOptions is used as a configuration class for FirestoreRecyclerAdapter to manage adapter data and provide query options. It allows developers to define the query options, sorting order, and layout if required.

Syntax

public class FirestoreRecyclerOptions<T extends Object>
    extends java.lang.Object

Constructors

FirestoreRecyclerOptions provides two constructors:

public FirestoreRecyclerOptions.Builder<T> newBuilder(Class<T> modelClass)

Creates a new builder instance.

FirestoreRecyclerOptions(FirebaseFirestore.Query query,
                          SnapshotParser<T> parser,
                          Decoder<T> decoder,
                          int limit,
                          int prefetchLimit,
                          boolean needsMetadata)

Creates a new instance.

Properties

FirestoreRecyclerOptions provides the following properties:

public FirebaseFirestore.Query getQuery()

Gets the query to fetch data from Firestore.

public SnapshotParser<T> getParser()

Gets the parser to use.

public Decoder<T> getDecoder()

Gets the decoder to use.

public int getLimit()

Gets the limit on how many items to fetch.

public int getPrefetchLimit()

Gets the prefetch limit.

public boolean needsMetadata()

Indicates whether metadata should be fetched or not.

Examples

Initializing FirestoreRecyclerOptions

To initialize FirestoreRecyclerOptions, you need to pass in a query and a model class.

Query query = FirebaseFirestore.getInstance().collection("users");
FirestoreRecyclerOptions<User> options = new FirestoreRecyclerOptions.Builder<User>()
        .setQuery(query, User.class)
        .build();

Using FirestoreRecyclerOptions with FirestoreRecyclerAdapter

FirestoreRecyclerOptions can be used with FirestoreRecyclerAdapter to populate a RecyclerView with Firestore data.

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

FirestoreRecyclerAdapter<User, UserViewHolder> adapter =
    new FirestoreRecyclerAdapter<User, UserViewHolder>(options) {
        @Override
        protected void onBindViewHolder(@NonNull UserViewHolder holder, int position, @NonNull User model) {
            holder.bind(model);
        }

        @NonNull
        @Override
        public UserViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(mContext).inflate(R.layout.list_item_user, parent, false);
            return new UserViewHolder(view);
        }
    };

Conclusion

FirestoreRecyclerOptions simplifies the implementation of Firestore Query with RecyclerView for Android developers. It provides an easy way to define the query options, sorting order, and layout of the RecyclerView without worrying too much about the implementation details.