Local Instant Search

Local Instant Search using RxBinding (Reactive Programming Project)

we will use RxBinding library for binding our search with our RecyclerView by making the typing of characters in the search as a stream of data (observable) and every time we type a character the RecyclerView get filtered.

Dependencies

Don't forget to add Java 8 to your gradle file

android {
    compileSdkVersion 28
    defaultConfig {
       ...
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    buildTypes {
        ...
    }
}

Then add these dependencies

dependencies {
    ...

    // RxJava & RxAndroid
    implementation 'io.reactivex.rxjava2:rxjava:2.1.9'
    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'

    // butter knife
    implementation "com.jakewharton:butterknife:8.8.1"
    annotationProcessor "com.jakewharton:butterknife-compiler:8.8.1"

    // RxBinding
    implementation "com.jakewharton.rxbinding2:rxbinding:2.0.0"
}

Libraries used

• ButterKnife: A library for binding any View (TextView, EditTextView, Button, RecyclerView…), Resource (Color, Drawable, String…) with the activity. For more details on how to use ButterKnife check this blog post.

• RxJava: Reactive eXtension library for implementing reactive programming for java.

• RxAndroid: Library for working with Schedulers of Reactive eXtension (Rx).

• RxBinding: check the introduction below.

Reactive Programming

if you're new to reactive programming or you want to know more, then check this article that i wrote on this subject that introduce and wrap up everything you need to know about reactive programming principles and core concepts and components:

Link to the article

Let's keep moving forward

RxBinding

RxBinding is library for RxJava that handles UI events (Click, Swipe…) and bind those using data streams. IT's basically UI interactions with simplified code. Especially when you have multiple event handling, the logic can be greatly simplified. Instead of using the combination of listeners, handlers and AsyncTasks, you can just implements RxJava and RxBinding. You also don't have to worry about threading problems and memory leaks since we're using Schedulers from the RxAndroid library.

Example Of Using RxBinding (Example used in the demo)

For more details, just go to the MainActivity of this repository

...

disposable.add(RxTextView.textChangeEvents(inputSearch)
                .skipInitialValue()
                .debounce(300, TimeUnit.MILLISECONDS)
                .distinctUntilChanged()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeWith(searchMoodsTextWatcher()));

...

The operators of Rx used in this example:

• debounce: delay time between emits.
• distinctUntilChanged: avoid repeating the same request twice in a row.

These operators will handle threading for us by specifying which schedulers will handles which task:

• subscribeOn: specify the scheduler that our obervables will operates on.
• observeOn: specify the scheduler on which we will oberve this observable.

The event used to listen to our Search EditTextView provided by RxBinding library

• RxTextView.textChangeEvents(someText): triggers an event to listen to any change to the text inside of the EditTextView