Query Firestore For Items To Be Displayed using RecyclerView in Recyclerview

Question

I have a list of math topics as documents in firebaseFirestore. The objects of these topics (documents) have a field called, rootTopic that can be used to categorize them into groups.

I would like to query the collection of these topics (documents) and display them in groups using a recyclerView-in-recyclerView as seen below

THE CHALLENGE IS:

I am not quite sure how best to dynamically query and group these topics(documents). Please assist with hints or snippets on how to achieve this.

Answer 1

There are two ways to query the data you want:

1. Make a query of the whole collection and group the results by the rootTopic field. Note that you'll need to partition the returned data, the data will just be ordered.

db.collection("Mathematics").orderBy("topicName")
// Then partition the results and render them.

2. Somehow get the list of different topicRoot and make a query for each of them by applying an equality filter. Here no need for partitioning code wise but several queries would be needed.

In any case I would suggest reading the documentation on queries and sorting cause it's pretty well explained there.

Answer 2

You should use multiple view types in a single recyclerView instead of multiple recyclerView. Here is one example article about it.