RxSearchView search

Question

My question is two fold. I had been using RxSearchView for a while. I have used map, filter and finally switchMap to query the search events from api. First in the map or filter function, I have updated the ui like this:

.filter(new Predicate<String>() {
                        @Override
                        public boolean test(String s) throws Exception {
                            if (searchViewQueryTextEvent.queryText().toString().length() < 3 && mUserList != null) {
                                mUserList.clear();
                            getActivity().runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    mUserSearchAdapter.notifyDataSetChanged();
                                }
                            });
                        }
                            return s.length() > 2;
                        }
                    })

So is it a good practice to keep updating the ui from inside these functions ? Secondly, deleting characters couldn't be handled this way. Please give me suggestions/ links. I am new to Rx. Thanks very much!

Answer 1

So is it a good practice to keep updating the ui from inside these functions ?

You do not need to and should not use runOnUIThread() here. You can add multiple calls to observeOn operators within your reactive chain to switch threads. Here are some links on threading :

• reactivex.io : Read about threading
• observeOn and subscribeOn : The subscribeOn and observeOn gifs on the blog make it easier to visualize the difference and use
• Common RxJava mistakes talk by Dan Lew: We can use observeOn multiple times.
• StackOverflow Post : Similar to what you need to achieve.

Secondly, deleting characters couldn't be handled this way. Please give me suggestions/ links.

Instead of filtering you should instead use debounce() operator. Here's a link to my talk at Droidcon Boston, 2017 in which I talk about auto-search problem with debounce() and switchMap() Scroll to ~ 25:00 time. You can find the demo code which handles deletion of characters as well and also the blog post.

I hope this helps.