done

app/build.gradle

@@ -47,4 +47,5 @@ dependencies {
     implementation libs.picasso
     implementation libs.rxjava
     implementation libs.rxandroid
+    implementation libs.adapter.rxjava2
 }

app/src/main/java/otus/homework/reactivecats/CatsService.kt

@@ -1,11 +1,12 @@
 package otus.homework.reactivecats
 
+import io.reactivex.Single
 import retrofit2.Call
 import retrofit2.http.GET
 
 interface CatsService {
 
     //@GET("random?animal_type=cat")
     @GET("fact")
-    fun getCatFact(): Call<Fact>
+    fun getCatFact(): Single<Fact>
 }

app/src/main/java/otus/homework/reactivecats/CatsViewModel.kt

@@ -1,55 +1,73 @@
 package otus.homework.reactivecats
 
 import android.content.Context
+import android.net.http.HttpException
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
+import io.reactivex.Flowable
+import io.reactivex.Observable
+import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.schedulers.Schedulers
+import okio.IOException
 import retrofit2.Call
 import retrofit2.Callback
 import retrofit2.Response
+import java.util.concurrent.TimeUnit
 
 class CatsViewModel(
-    catsService: CatsService,
-    localCatFactsGenerator: LocalCatFactsGenerator,
-    context: Context
+    private val catsService: CatsService,
+    private val localCatFactsGenerator: LocalCatFactsGenerator
 ) : ViewModel() {
 
     private val _catsLiveData = MutableLiveData<Result>()
     val catsLiveData: LiveData<Result> = _catsLiveData
+    private val сompositeDisposable = CompositeDisposable()
 
     init {
-        catsService.getCatFact().enqueue(object : Callback<Fact> {
-            override fun onResponse(call: Call<Fact>, response: Response<Fact>) {
-                if (response.isSuccessful && response.body() != null) {
-                    _catsLiveData.value = Success(response.body()!!)
-                } else {
-                    _catsLiveData.value = Error(
-                        response.errorBody()?.string() ?: context.getString(
-                            R.string.default_error_text
-                        )
-                    )
-                }
-            }
+        getFacts()
+    }
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                _catsLiveData.value = ServerError
+    fun getFacts() {
+
+        val disposable = Observable.interval(0, 2000, TimeUnit.MILLISECONDS)
+            .flatMapSingle {
+                catsService.getCatFact().onErrorResumeNext { localCatFactsGenerator.generateCatFact() }
             }
-        })
+            .subscribeOn(Schedulers.io())
+            .distinctUntilChanged()
+            .observeOn(AndroidSchedulers.mainThread())
+            .subscribe({
+                _catsLiveData.value = Success(it)
+            }, {
+                when (it) {
+                    is IOException -> {
+                        _catsLiveData.value = ServerError
+                    }
+                    else -> {
+                        _catsLiveData.value = Error(it.message.toString())
+                    }
+                }
+            })
+        сompositeDisposable.add(disposable)
     }
 
-    fun getFacts() {}
+    override fun onCleared() {
+        super.onCleared()
+        сompositeDisposable.dispose()
+    }
 }
 
 class CatsViewModelFactory(
     private val catsRepository: CatsService,
-    private val localCatFactsGenerator: LocalCatFactsGenerator,
-    private val context: Context
+    private val localCatFactsGenerator: LocalCatFactsGenerator
 ) :
     ViewModelProvider.NewInstanceFactory() {
 
     override fun <T : ViewModel> create(modelClass: Class<T>): T =
-        CatsViewModel(catsRepository, localCatFactsGenerator, context) as T
+        CatsViewModel(catsRepository, localCatFactsGenerator) as T
 }
 
 sealed class Result

app/src/main/java/otus/homework/reactivecats/DiContainer.kt

@@ -2,6 +2,7 @@ package otus.homework.reactivecats
 
 import android.content.Context
 import retrofit2.Retrofit
+import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
 import retrofit2.converter.gson.GsonConverterFactory
 
 class DiContainer {
@@ -11,6 +12,7 @@ class DiContainer {
             //.baseUrl("https://cat-fact.herokuapp.com/facts/")
             .baseUrl("https://catfact.ninja/")
             .addConverterFactory(GsonConverterFactory.create())
+            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
             .build()
     }
 

app/src/main/java/otus/homework/reactivecats/LocalCatFactsGenerator.kt

@@ -3,6 +3,10 @@ package otus.homework.reactivecats
 import android.content.Context
 import io.reactivex.Flowable
 import io.reactivex.Single
+import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.schedulers.Schedulers
+import io.reactivex.subscribers.DisposableSubscriber
+import java.util.concurrent.TimeUnit
 import kotlin.random.Random
 
 class LocalCatFactsGenerator(
@@ -15,7 +19,8 @@ class LocalCatFactsGenerator(
      * обернутую в подходящий стрим(Flowable/Single/Observable и т.п)
      */
     fun generateCatFact(): Single<Fact> {
-        return Single.never()
+        val success = context.resources.getStringArray(R.array.local_cat_facts)[Random.nextInt(5)]
+        return Single.just(Fact(success))
     }
 
     /**
@@ -24,7 +29,12 @@ class LocalCatFactsGenerator(
      * Если вновь заэмиченный Fact совпадает с предыдущим - пропускаем элемент.
      */
     fun generateCatFactPeriodically(): Flowable<Fact> {
-        val success = Fact(context.resources.getStringArray(R.array.local_cat_facts)[Random.nextInt(5)])
-        return Flowable.empty()
+        val factsArray = context.resources.getStringArray(R.array.local_cat_facts)
+        return Flowable.interval(0, 2000, TimeUnit.MILLISECONDS)
+            .map {
+                val randomFact = factsArray[Random.nextInt(factsArray.size)]
+                Fact(randomFact)
+            }
+            .distinctUntilChanged()
     }
 }

app/src/main/java/otus/homework/reactivecats/MainActivity.kt

@@ -13,8 +13,7 @@ class MainActivity : AppCompatActivity() {
     private val catsViewModel by viewModels<CatsViewModel> {
         CatsViewModelFactory(
             diContainer.service,
-            diContainer.localCatFactsGenerator(applicationContext),
-            applicationContext
+            diContainer.localCatFactsGenerator(applicationContext)
         )
     }
 

gradle/libs.versions.toml

@@ -17,6 +17,7 @@ rxandroid = "2.1.1"
 rxjava = "2.2.21"
 
 [libraries]
+adapter-rxjava2 = { module = "com.squareup.retrofit2:adapter-rxjava2", version.ref = "retrofit" }
 core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "core-ktx" }
 appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
 material = { group = "com.google.android.material", name = "material", version.ref = "material" }