Android Animation: from hate to love

android:toYDelta="200" />

private fun startAnimation(view: View) { val animation =

AnimationUtils.loadAnimation(this, R.anim.view_animation) view.startAnimation(animation) }

.translationY(200f) .setDuration(250) .start() }

xmlns:android="http://schemas.android.com/apk/res/android">

.translationY(200f) .rotation(180f) .setDuration(400)

.start() }

.translationY(200f) .rotation(180f) .scaleY(3f)

.scaleX(4f) .setDuration(400) .start() }

Property animator

fun startAnimation(reverse: Boolean) { TransitionManager.beginDelayedTransition(main_container) (if (reverse) startSet

else endSet).applyTo(main_container) }

Scene.getSceneForLayout(main_container, R.layout.scene_a, this)

this, cat,

getString(R.string.cat_transition) ).toBundle() startActivity( Intent(this, CatInfoActivity::class.java), bundle ) }

name="android:windowActivityTransitions">true @transition/cat_open @transition/cat_open

android:id="@+id/motion_container" android:layout_width="match_parent" android:layout_height="match_parent" app:layoutDescription="@xml/scene" tools:showPaths="true">

motion:constraintSetEnd="@+id/end" motion:constraintSetStart="@+id/start" motion:duration="1000">

/>

/>

android:id="@+id/motion_container" android:layout_width="match_parent" android:layout_height="match_parent" app:layoutDescription="@xml/scene" tools:showPaths="true">

developer

выполнение команд, и внешних синхронных операций.

Реактивный подход — парадигма программирования, ориентированная

на потоки данных и асинхронное распространение изменений.

вхождения
Высокая сложность

getUserBalance(userId: String): BigDecimal fun updateUserBalance(userId: String, balance: BigDecimal) } private val

manager: IUserManager = UserManager() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val user = manager.getUser() val balance = manager.getUserBalance(user.id) val newBalance = balance - payment manager.updateUserBalance(user.id, newBalance) view.showSnack("Balance has been updated to $newBalance")

onError: (Throwable) -> Unit) fun getUserBalance(userId: String, onSuccess: (BigDecimal)

-> Unit, onError: (Throwable) -> Unit) fun updateUserBalance(userId: String, balance: BigDecimal, onSuccess: () -> Unit, onError: (Throwable) -> Unit) } private val manager: IUserManager = UserManager() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) manager.getUser( onSuccess = { user -> manager.getUserBalance( userId = user.id, onSuccess = { balance -> val newBalance = balance - payment manager.updateUserBalance( userId = user.id, balance = newBalance, onSuccess = { view.showSnack("balance updated") }, onError = ::processError ) }, onError = ::processError ) }, onError = ::processError ) } private fun processError(th: Throwable) { ... }

onError: (Throwable) -> Unit) fun getUserBalance(userId: String, onSuccess: (BigDecimal)

-> Unit, onError: (Throwable) -> Unit) fun updateUserBalance(userId: String, balance: BigDecimal, onSuccess: () -> Unit, onError: (Throwable) -> Unit) } private val manager: IUserManager = UserManager() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) manager.getUser( onSuccess = { user -> manager.getUserBalance( userId = user.id, onSuccess = { balance -> val newBalance = balance - payment manager.updateUserBalance( userId = user.id, balance = newBalance, onSuccess = { view.showSnack("balance updated") }, onError = ::processError ) }, onError = ::processError ) }, onError = ::processError ) } private fun processError(th: Throwable) { ... }

Слишком сложно

getUserBalance(userId: String): Single fun updateUserBalance(userId: String, balance: BigDecimal): Completable } private

val manager: IUserManager = UserManager() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) manager.getUser() .flatMapCompletable { user -> manager.getUserBalance(user.id) .map { balance -> balance - cost } .flatMap { balance -> updateUserBalance(user.id, balance) } } .subscribe( onSuccess = { view.showSnack("balance updated") }, onError = ::processError ) }

Android LiveData
https://developer.android.com/topic/libraries/architecture/livedata
4. Reactor, Akka, ets..
Реализация реактивного

подхода в android

library for composing asynchronous and event-based programs by using observable

sequences.

Основные паттерны
Observable
Observer (Subscriber)
Operators
Subscription
Schedulers

rxjava

Observable на разных потоках Schedulers.io() Schedulers.computation() Schedulers.newThread() Schedulers.single() Schedulers.from(Executor executor) AndroidSchedulers.mainThread() RxAndroid — библиотека для RxJava, реализующая AndroidScheduler

для выполнения задач на основном потоке андроид приложения https://github.com/ReactiveX/RxAndroid

Rxjava shedulers. rxandroid

getItemsFromRemoteSource() .doOnNext { item -> Log.d(TAG, "Emitting item $item on thread ${currentThread().name}") } .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .doOnNext { item -> Log.d(TAG, "Consuming item $item on thread ${currentThread().name}") } .subscribe { item -> showItem(item) }

жизненный цикл activity/fragment
class SampleActivity: AppCompatActivity() { private val presenter:

SamplePresenter = SamplePresenter() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) presenter.observeModel() .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.main()) .subscribe( { model -> bindModel(model) }, { th -> bindError(th) } ) } private fun bindModel(model: Model) { ... } private fun bindError(th: Throwable) { ... } }

жизненный цикл activity/fragment
class SampleActivity: AppCompatActivity() { @Inject lateinit

var presenter: SamplePresenter private var modelSubscription: Subscription? = null override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState, persistentState) ComponentManager.mainComponent.inject(this) } override fun onStart() { super.onStart() modelSubscription = presenter.observeModel() .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.main()) .subscribe( { model -> bindModel(model) }, { th -> bindError(th) } ) } override fun onStop() { super.onStop() modelSubscription?.unsubscribe() } }

компонентов андроида
https://github.com/trello/RxLifecycle
Rxjava и жизненный цикл activity/fragment. rxlifecyrcle
class SampleActivity: RxActivity() {

@Inject lateinit var presenter: SamplePresenter override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) ComponentManager.mainComponent.inject(this) presenter.observeModel() .subscribeOn(Schedulers.io()) .compose(bindToLifecycle()) .subscribe( { userInfo -> bindUserInfo() }, { th -> bindError() } ) } }

таймер)

Ретраи запроса (поллинг)

…
Rxjava. Типичные варианты применения

Inc.
https://square.github.io/retrofit/

Rxjava и Retrofit. Реактивный поход в сеть
interface ScalaApi {

@GET("magazine/articles/snippets") fun getJournalArticles( @Query("category") articleCategory: Array, @Query("mark") mark: String, @Query("model") model: String, @Query("super_gen_id") superGen: String?, @Query("page_size") pageSize: Int ): Single @GET("user/offers/{category}") fun getUserOffers( @Path("category") category: String = "all", @Query("page") page: Int, @Query("sort") sort: String?, @Query("page_size") pageSize: Int, @Query("with_daily_counters") withDailyViews: Boolean = false, @Query("moto_category") motoCategory: List? = null, @Query("truck_category") truckCategory: List? = null, @Query("section") state: String? = null, @Query("status") status: String? = null, @Query("mark_model") markModel: String? = null, @Query("price_from") priceFrom: Int? = null

implementation "com.squareup.retrofit2:retrofit:$retrofit" implementation "com.squareup.retrofit2:converter-gson:$retrofit" implementation("com.squareup.retrofit2:converter-protobuf:$retrofit") { transitive = false; } implementation "com.squareup.retrofit2:adapter-rxjava:$retrofit"

private val userRepo: IUserOffersRepository, private val geoRepository: IGeoRepository,

private val recentBadgesRepository: IRecentBadgesRepository ) : IOfferDetailsInteractor { override fun getOffer( category: String, offerId: String, isUserOffer: Boolean, rids: List?, geoRadius: Int? ): Single = Single.zip( recentBadgesRepository.observeBadges().take(1).toSingle(), getOffer(isUserOffer, category, offerId, rids, geoRadius), { badges, offer -> offer.enrichWithRecentBadges(badges) } ) .doOnSuccess { cacheOffer(it) } private fun getOffer( isUserOffer: Boolean, category: String, offerId: String, rids: List?, geoRadius: Int? ): Single = when { isUserOffer -> offersRepository.getUserOffer(category, offerId) else -> offersRepository.getOffer(category, offerId, rids, geoRadius) } }

private val eventsSubj = PublishSubject.create().toSerialized() override fun switchFavorite(favorite: Offer):

Completable = when { favoriteRepo.idsCache.contains(favorite.id) -> removeFavorite(favorite) else -> addFavorite(favorite) } override fun favoriteSwitchEvents(): Observable> = eventsSubj }