I, Preamble

• Hello everyone, today I will introduce to you how to implement SearchView with many filters using RxJava in Android with my experience.
• This is also the last article in the series Create 1 Search app complete with SearchView, RxJava and its data binding .
• If people have not refer to their previous posts, you can refer to:
  • Part 1 : Custom SearchView is similar to google search – Link .
  • Part 2 : Implement SearchView without filter with RxJava – Link .
• Taking advantage of the results achieved in part 1 and part 2, we will do this part 3.

II, The problem and how to do it

1, The problem

• We have 2 sources of data returned from the server (similar to the database) to display together when the user searches.
• Searching for Tag by repo.getTags () return Observable <List <Tag >> and search Post by repo.getPosts () return Observable <ListPost >>.
• For each word the user fills in the SearchView will produce the corresponding tags and posts.
• Filter condition: you can search by keyboard or tag (search results).

2, How to do it

• In order to solve this problem, we need 2 important steps if we only choose to use 1 Adapter:

  • Step 1 : Create a wrap object – SearchResult to wrap 2 Tag and Post objects. Each SearchResult can contain 1 List of tags or only 1 Post
  • Step 2 : Based on the terms: Use the word Zip to combine 2 data sources to have a SearchResult list displayed for the user.

• To better understand what people can observe the image below:

• Note : You can also use MergeAdapter when you intend to use multiple Adapters but I will not give in this article.

• Step 1: Create combine object – SearchResult.

• Tag object:

• Post object:

• SearchResult object:

• Step 2: Zip 2 data sources according to filter conditions:

• Note : Do not forget that each time the user searches we need to recognize when the user searches with the keyboard and when to search with the tag.

III, Summary

• Above is my experience when doing RxJava search with many filters.
• With Android, we also have some other tools and directions to solve this problem such as MergerAdapter, coroutine …
• It has been a long time since there has been no new knowledge for everyone, so the following article will share carefully every corner of power tool / design: coroutine .
• There may be many people who have read through and know about this problem but I still want to dig into every corner of it.
• Happy coding!