从 Firestore 获取数据后，如何使用 Flutter 创建线程评论？

Question

I am developing a flutter application that can support threaded comments similar to Reddit, HackerNews.

I am using Firestore. Here is the structure I am using now:

Comment
    id
    parent_post_id
    parent_comment_id
    children_comment_id
    timeStamp
    author_id
    points

However, when I query for the comments using

firestore.collection('comments')
          .where('postID', isEqualTo: postID)
          .orderBy('createdAt', descending: true)

I get all the comments, including the replies but the replies of a comment are not placed directly under the parent comment.

I need the ability to rearrange the comments in the app after getting the data from Firestore and place the replies directly below their parents and arrange them according to date. How can I go about doing this? Thanks.

Answer 1

You will have to write code in your app to rearrange the query results after they become available in the app. Firestore really can't help you out with sorting on anything other than the contents of individual fields in their natural (or reverse) sort order. You can't instruct Firestore to interleave results based on other complex conditions.

All of the sorting capabilities for Firestore is covered fully in the documentation , so you should review that to understand the limits.