Deep press observable for customize backspace view

DeepPress.java

/*
 * Copyright 2017 "Henry Tao <hi@henrytao.me>"
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.squar.mychat.util;

import android.view.MotionEvent;
import android.view.View;

import java.util.concurrent.TimeUnit;

import rx.Observable;
import rx.Subscription;
import rx.android.schedulers.AndroidSchedulers;
import rx.subjects.PublishSubject;

/**
 * Created by henrytao on 01/24/17.
 */

public class DeepPress implements View.OnTouchListener {

  private static final int DELAY = 200;

  private static final int INTERVAL = 90;

  public static DeepPress on(View view, int interval) {
    return new DeepPress(view, interval);
  }

  public static DeepPress on(View view) {
    return on(view, INTERVAL);
  }

  private final int mInterval;

  private final View mView;

  private PublishSubject<Boolean> mSubject;

  private Subscription mTimerSubscription;

  private DeepPress(View view, int interval) {
    mView = view;
    mInterval = interval;
  }

  @Override
  public boolean onTouch(View view, MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        onActionDown();
        break;
      case MotionEvent.ACTION_UP:
        onActionUp();
        break;
    }
    return true;
  }

  public Observable<Boolean> observe() {
    mView.setOnTouchListener(this);
    mSubject = PublishSubject.create();
    return mSubject.doOnUnsubscribe(this::onUnsubscribe);
  }

  private void onActionDown() {
    resetTimer();
    mSubject.onNext(true);
    mTimerSubscription = Observable.timer(DELAY, TimeUnit.MILLISECONDS)
        .flatMap(aLong -> Observable.interval(mInterval, TimeUnit.MILLISECONDS))
        .onBackpressureBuffer()
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(aLong -> mSubject.onNext(true));
  }

  private void onActionUp() {
    resetTimer();
    mSubject.onNext(false);
  }

  private void onUnsubscribe() {
    resetTimer();
    mSubject.onCompleted();
    mView.setOnTouchListener(null);
  }

  private void resetTimer() {
    if (mTimerSubscription != null && !mTimerSubscription.isUnsubscribed()) {
      mTimerSubscription.unsubscribe();
    }
  }
}