Lisitsa Ilya - HomeWork Rx.

app/build.gradle

@@ -4,13 +4,13 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
     buildToolsVersion "30.0.3"
 
     defaultConfig {
         applicationId "otus.homework.reactivecats"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
 
@@ -46,4 +46,7 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
     implementation "io.reactivex.rxjava2:rxjava:2.2.21"
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
+
+    // Retrofit
+    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.9.0'
 }

app/src/main/AndroidManifest.xml

@@ -11,7 +11,9 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.ReactiveCats">
-        <activity android:name=".MainActivity">
+        <activity
+            android:exported="true"
+            android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

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

@@ -1,10 +1,10 @@
 package otus.homework.reactivecats
 
-import retrofit2.Call
+import io.reactivex.Single
 import retrofit2.http.GET
 
 interface CatsService {
 
     @GET("random?animal_type=cat")
-    fun getCatFact(): Call<Fact>
+    fun getCatFact(): Single<Fact>
 }

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

@@ -1,58 +1,73 @@
 package otus.homework.reactivecats
 
-import android.content.Context
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import io.reactivex.Observable
+import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.disposables.CompositeDisposable
+import java.util.concurrent.TimeUnit
+
 
 class CatsViewModel(
-    catsService: CatsService,
-    localCatFactsGenerator: LocalCatFactsGenerator,
-    context: Context
+    private val catsService: CatsService,
+    private val localCatFactsGenerator: LocalCatFactsGenerator,
+    private val subscriptions: CompositeDisposable
 ) : ViewModel() {
 
     private val _catsLiveData = MutableLiveData<Result>()
     val catsLiveData: LiveData<Result> = _catsLiveData
 
     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()
+    }
+
+    private fun getFacts() {
+        val initialDelay = 0L
+        val period = 2L
+        val timeUnit = TimeUnit.SECONDS
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                _catsLiveData.value = ServerError
+        val disposable = Observable.interval(initialDelay, period, timeUnit)
+            .flatMap {
+                catsService.getCatFact().toObservable()
             }
-        })
+            .onErrorResumeNext(
+                localCatFactsGenerator.generateCatFactPeriodically().toObservable()
+            )
+            .observeOn(AndroidSchedulers.mainThread())
+            .subscribe(::doOnSuccessReceiveFact, ::doOnError)
+
+        subscriptions.add(disposable)
     }
 
-    fun getFacts() {}
+    override fun onCleared() {
+        super.onCleared()
+
+        subscriptions.clear()
+    }
+
+    private fun doOnSuccessReceiveFact(fact: Fact) {
+        _catsLiveData.value = Success(fact)
+    }
+
+    private fun doOnError(throwable: Throwable) {
+        throwable.printStackTrace()
+        _catsLiveData.value = Error(message = throwable.localizedMessage)
+    }
 }
 
 class CatsViewModelFactory(
     private val catsRepository: CatsService,
     private val localCatFactsGenerator: LocalCatFactsGenerator,
-    private val context: Context
+    private val subscriptions: CompositeDisposable
 ) :
     ViewModelProvider.NewInstanceFactory() {
     @Suppress("UNCHECKED_CAST")
     override fun <T : ViewModel?> create(modelClass: Class<T>): T =
-        CatsViewModel(catsRepository, localCatFactsGenerator, context) as T
+        CatsViewModel(catsRepository, localCatFactsGenerator, subscriptions) as T
 }
 
 sealed class Result
 data class Success(val fact: Fact) : Result()
-data class Error(val message: String) : Result()
-object ServerError : Result()
+data class Error(val message: String?) : Result()

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

@@ -1,7 +1,9 @@
 package otus.homework.reactivecats
 
 import android.content.Context
+import io.reactivex.disposables.CompositeDisposable
 import retrofit2.Retrofit
+import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
 import retrofit2.converter.gson.GsonConverterFactory
 
 class DiContainer {
@@ -10,10 +12,13 @@ class DiContainer {
         Retrofit.Builder()
             .baseUrl("https://cat-fact.herokuapp.com/facts/")
             .addConverterFactory(GsonConverterFactory.create())
+            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
             .build()
     }
 
-    val service by lazy { retrofit.create(CatsService::class.java) }
+    val service: CatsService by lazy { retrofit.create(CatsService::class.java) }
+
+    val subscriptions: CompositeDisposable = CompositeDisposable()
 
     fun localCatFactsGenerator(context: Context) = LocalCatFactsGenerator(context)
 }

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

@@ -3,7 +3,8 @@ package otus.homework.reactivecats
 import android.content.Context
 import io.reactivex.Flowable
 import io.reactivex.Single
-import kotlin.random.Random
+import io.reactivex.schedulers.Schedulers
+import java.util.concurrent.TimeUnit
 
 class LocalCatFactsGenerator(
     private val context: Context
@@ -15,7 +16,17 @@ class LocalCatFactsGenerator(
      * обернутую в подходящий стрим(Flowable/Single/Observable и т.п)
      */
     fun generateCatFact(): Single<Fact> {
-        return Single.never()
+        return Single.create<Fact> { singleEmitter ->
+            try {
+                val items = context.resources.getStringArray(R.array.local_cat_facts)
+                val randomItem = items.random()
+                val factItem = Fact(text = randomItem)
+
+                singleEmitter.onSuccess(factItem)
+            } catch (throwable: Throwable) {
+                singleEmitter.onError(throwable)
+            }
+        }.subscribeOn(Schedulers.computation())
     }
 
     /**
@@ -24,7 +35,12 @@ 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 repeatTime = 2L
+        val timeUnit = TimeUnit.SECONDS
+        val newFlowableCatsFact = generateCatFact().toFlowable()
+
+        return Flowable.interval(repeatTime, timeUnit)
+            .flatMap { newFlowableCatsFact }
+            .distinctUntilChanged()
     }
 }

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

@@ -1,11 +1,9 @@
 package otus.homework.reactivecats
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import android.widget.Toast
 import androidx.activity.viewModels
-import androidx.lifecycle.lifecycleScope
-import com.google.android.material.snackbar.Snackbar
+import androidx.appcompat.app.AppCompatActivity
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,7 +12,7 @@ class MainActivity : AppCompatActivity() {
         CatsViewModelFactory(
             diContainer.service,
             diContainer.localCatFactsGenerator(applicationContext),
-            applicationContext
+            diContainer.subscriptions
         )
     }
 
@@ -25,8 +23,12 @@ class MainActivity : AppCompatActivity() {
         catsViewModel.catsLiveData.observe(this) { result ->
             when (result) {
                 is Success -> view.populate(result.fact)
-                is Error -> Toast.makeText(this, result.message, Toast.LENGTH_LONG).show()
-                ServerError -> Snackbar.make(view, "Network error", 1000).show()
+                is Error -> {
+                    val error = result.message
+                        ?: applicationContext.getString(R.string.default_error_text)
+
+                    Toast.makeText(this, error, Toast.LENGTH_LONG).show()
+                }
             }
         }
     }

build.gradle

@@ -1,12 +1,12 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = "1.4.32"
+    ext.kotlin_version = '1.6.21'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
     dependencies {
-        classpath "com.android.tools.build:gradle:4.1.2"
+        classpath 'com.android.tools.build:gradle:7.0.4'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong
@@ -17,8 +17,8 @@ buildscript {
 allprojects {
     repositories {
         google()
+        mavenCentral()
 //        maven { url "https://oss.jfrog.org/libs-snapshot" }
-        jcenter()
     }
 }
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Jun 11 16:59:36 MSK 2021
+#Wed May 04 20:13:31 MSK 2022
 distributionBase=GRADLE_USER_HOME
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1.1-bin.zip
 distributionPath=wrapper/dists
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-all.zip
+zipStoreBase=GRADLE_USER_HOME