RxAndroid - EditText watcher

RxTextView.java

//------------------------------------------------------------------------------
// RXTextView
//------------------------------------------------------------------------------

import android.support.annotation.NonNull;
import android.widget.TextView;

import rx.Observable;

public final class RxTextView {

    private RxTextView() {
    }

    @NonNull
    public static Observable<CharSequence> textChanges(@NonNull TextView view) {
        return Observable.create(new TextViewTextOnSubscribe(view));
    }
}

TextViewTextOnSubscribe.java

//------------------------------------------------------------------------------
// TextViewTextOnSubscribe - just package private for RxTextView to use
//------------------------------------------------------------------------------

import android.text.Editable;
import android.text.TextWatcher;
import android.widget.TextView;

import rx.Observable;
import rx.Subscriber;
import rx.android.MainThreadSubscription;

import static rx.android.MainThreadSubscription.verifyMainThread;

final class TextViewTextOnSubscribe
        implements Observable.OnSubscribe<CharSequence> {

    final TextView view;

    TextViewTextOnSubscribe(TextView view) {
        this.view = view;
    }

    @Override
    public void call(final Subscriber<? super CharSequence> subscriber) {
        verifyMainThread();

        final TextWatcher watcher = new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                if (!subscriber.isUnsubscribed()) {
                    subscriber.onNext(s);
                }
            }

            @Override
            public void afterTextChanged(Editable s) {
            }
        };

        subscriber.add(new MainThreadSubscription() {
            @Override
            protected void onUnsubscribe() {
                view.removeTextChangedListener(watcher);
            }
        });

        view.addTextChangedListener(watcher);

        // Emit initial value.
        subscriber.onNext(view.getText());
    }
}

usage.java

Subscription editTextSub = RxTextView.textChanges(editText)
            .subscribe(new Action1<String>() {
                @Override
                public void call(String value) {
                    // do some work with the updated text
                }
            });