CoderJava

@Database(entities = [(WaktuData::class)], version = 1)
abstract class WaktuDb : RoomDatabase() {

    abstract fun waktuDao(): WaktuDao

    companion object {
        private var INSTANCE: WaktuDb? = null

        fun getInstance(context: Context) : WaktuDb? {
            if (INSTANCE == null) {

CoderJava

// ...
button_database.setOnClickListener { it ->
    val waktuDb: WaktuDb = WaktuDb.getInstance(this@MainActivity)!!
    Observable
            .create<Boolean> { emitter ->
                val strWaktu = SimpleDateFormat("dd-MM-yyyy HH:mm:ss", Locale.US)
                        .format(Date())
                val waktuData = WaktuData(null, strWaktu)
                waktuDb.waktuDao()
                        .insert(waktuData)

CoderJava

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.ysn.stethodev"
        minSdkVersion 19

CoderJava

import android.content.Context;
import android.content.SharedPreferences;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;

CoderJava

import io.reactivex.Observable;
import io.reactivex.ObservableOnSubscribe;

public class RxOperatorCreate {
    public static void main(String[] args) {
        Observable
                .create((ObservableOnSubscribe<String>) emitter -> {
                    emitter.onNext("Yudi Setiawan");
                    emitter.onComplete();
                })

CoderJava

public class RxOperatorDefer {
    public static void main(String[] args) {
        User user = new User();
        Observable<String> name = user.getName();
        user.setName("Yudi Setiawan");
        name.subscribe(System.out::println);
    }
}

class User {

CoderJava

public class RxOperatorFrom {
    public static void main(String[] args) {
        String[] names = new String[]{"Yudi Setiawan", "Harli Lopies", "Rosalia"};
        Observable.fromArray(names)
                .subscribe(System.out::println);
    }
}

CoderJava

public class RxOperatorInterval {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(1);
        Observable.interval(1000 * 2, TimeUnit.MILLISECONDS)
                .subscribe(new Observer<Long>() {
                    @Override
                    public void onSubscribe(Disposable d) {
                        System.out.println("onSubscribe");
                    }

CoderJava

public class RxOperatorJust {
    public static void main(String[] args) {
        String[] names = new String[]{"Yudi Setiawan", "Harli Lopies", "Rosalia"};
        Observable.just(names)
                .subscribe(strings -> System.out.println(Arrays.toString(strings)));
    }
}

CoderJava

public class Main {
    public static void main(String[] args) {
        Observable.range(0, 5)
                .subscribe(System.out::println);
    }
}