HW - Ilya Lisitsa Flow

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 = '1.6.20'
     repositories {
         google()
         jcenter()
     }
     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

flowcats/build.gradle

@@ -4,13 +4,13 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
     buildToolsVersion "30.0.3"
 
     defaultConfig {
         applicationId "otus.homework.flowcats"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
 
@@ -37,7 +37,7 @@ dependencies {
     implementation 'androidx.core:core-ktx:1.3.2'
     implementation 'com.squareup.retrofit2:retrofit:2.9.0'
     implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
-    implementation 'com.google.code.gson:gson:2.8.6'
+    implementation 'com.google.code.gson:gson:2.8.7'
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'com.google.android.material:material:1.3.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
@@ -46,4 +46,5 @@ dependencies {
     implementation 'androidx.activity:activity-ktx:1.2.3'
     testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
+    implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.5.0-beta01"
 }

flowcats/src/main/AndroidManifest.xml

@@ -9,8 +9,10 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/Theme.Flow" >
-        <activity android:name=".MainActivity">
+        android:theme="@style/Theme.Flow">
+        <activity
+            android:name=".MainActivity"
+            android:exported="false">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

flowcats/src/main/java/otus/homework/flowcats/CatsRepository.kt

@@ -1,18 +1,28 @@
 package otus.homework.flowcats
 
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.emitAll
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 
 class CatsRepository(
     private val catsService: CatsService,
+    private val backgroundDispatcher: CoroutineDispatcher = Dispatchers.IO,
     private val refreshIntervalMs: Long = 5000
 ) {
 
-    fun listenForCatFacts() = flow {
+    fun listenForCatFacts(): Flow<Result<Fact>> = flow<Result<Fact>> {
         while (true) {
             val latestNews = catsService.getCatFact()
-            emit(latestNews)
+            emit(Success(latestNews))
             delay(refreshIntervalMs)
         }
-    }
+    }.catch {
+        emit(Error)
+        emitAll(listenForCatFacts())
+    }.flowOn(backgroundDispatcher)
 }

flowcats/src/main/java/otus/homework/flowcats/CatsView.kt

@@ -3,6 +3,7 @@ package otus.homework.flowcats
 import android.content.Context
 import android.util.AttributeSet
 import android.widget.TextView
+import android.widget.Toast
 import androidx.constraintlayout.widget.ConstraintLayout
 
 class CatsView @JvmOverloads constructor(
@@ -11,12 +12,42 @@ class CatsView @JvmOverloads constructor(
     defStyleAttr: Int = 0
 ) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
 
-    override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.text
+    private val tvFact by lazy {
+        findViewById<TextView>(R.id.fact_textView)
+    }
+
+    override fun populate(result: Result<Fact>) {
+        when (result) {
+            is Loading -> {
+                doOnLoading()
+            }
+            is Success -> {
+                doOnSuccess(result.data)
+            }
+            is Error -> {
+                doOnError()
+            }
+        }
+
+    }
+
+    private fun doOnLoading() {
+        tvFact.text = context.getString(R.string.loading_state_text)
+    }
+
+    private fun doOnSuccess(fact: Fact) {
+        tvFact.text = fact.text
+    }
+
+    private fun doOnError() {
+        val errorMessage = context.getString(R.string.error_state_text)
+        val toast = Toast.makeText(context, errorMessage, Toast.LENGTH_SHORT)
+
+        toast.show()
     }
 }
 
 interface ICatsView {
 
-    fun populate(fact: Fact)
+    fun populate(result: Result<Fact>)
 }

flowcats/src/main/java/otus/homework/flowcats/CatsViewModel.kt

@@ -1,27 +1,23 @@
 package otus.homework.flowcats
 
-import androidx.lifecycle.*
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.stateIn
 
 class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
-
-    init {
-        viewModelScope.launch {
-            withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
-            }
-        }
-    }
+    val catsStateFlow: StateFlow<Result<Fact>> = catsRepository
+        .listenForCatFacts()
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5000),
+            initialValue = Loading
+        )
 }
 
 class CatsViewModelFactory(private val catsRepository: CatsRepository) :

flowcats/src/main/java/otus/homework/flowcats/DiContainer.kt

@@ -12,7 +12,7 @@ class DiContainer {
             .build()
     }
 
-    val service by lazy { retrofit.create(CatsService::class.java) }
+    private val service: CatsService by lazy { retrofit.create(CatsService::class.java) }
 
     val repository by lazy { CatsRepository(service) }
 }

flowcats/src/main/java/otus/homework/flowcats/MainActivity.kt

@@ -1,21 +1,35 @@
 package otus.homework.flowcats
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
     private val diContainer = DiContainer()
-    private val catsViewModel by viewModels<CatsViewModel> { CatsViewModelFactory(diContainer.repository) }
+    private val catsViewModel by viewModels<CatsViewModel> {
+        CatsViewModelFactory(diContainer.repository)
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
+        initCollectingViewItems(view)
+    }
+
+    private fun initCollectingViewItems(view: CatsView) {
+        lifecycleScope.launch {
+            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
+                catsViewModel.catsStateFlow.collect { result ->
+                    view.populate(result)
+                }
+            }
         }
     }
 }

flowcats/src/main/java/otus/homework/flowcats/Result.kt

@@ -0,0 +1,6 @@
+package otus.homework.flowcats
+
+sealed class Result<out T>
+class Success<out T>(val data: T) : Result<T>()
+object Loading : Result<Nothing>()
+object Error : Result<Nothing>()

flowcats/src/main/res/values/strings.xml

@@ -1,3 +1,5 @@
 <resources>
     <string name="app_name">Flow cats</string>
+    <string name="loading_state_text">Loading…</string>
+    <string name="error_state_text">Default error</string>
 </resources>

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed May 05 23:18:49 MSK 2021
+#Sat Apr 23 10:36:49 MSK 2022
 distributionBase=GRADLE_USER_HOME
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-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

operators/src/main/java/otus/homework/flow/SampleInteractor.kt

@@ -1,7 +1,14 @@
 package otus.homework.flow
 
 import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onCompletion
+import kotlinx.coroutines.flow.take
+import kotlinx.coroutines.flow.transform
+import kotlinx.coroutines.flow.zip
 
 @ExperimentalCoroutinesApi
 class SampleInteractor(
@@ -10,15 +17,20 @@ class SampleInteractor(
 
     /**
      * Реализуйте функцию task1 которая последовательно:
-     * 1) возводит числа в 5ую степень
+     * 1) возводит числа в 5ую степень // У вас тут ошибка если делать как тут написано то тест никогда не пройдется) я так понимаю тут перемножение на 5 имелось ввиду, а не степень
      * 2) убирает чила <= 20
      * 3) убирает четные числа
      * 4) добавляет постфикс "won"
      * 5) берет 3 первых числа
      * 6) возвращает результат
      */
     fun task1(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .map { it * 5 }
+            .filter { it > 20 }
+            .filter { it % 2 != 0 }
+            .map { "$it won" }
+            .take(3)
     }
 
     /**
@@ -29,7 +41,8 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .fizzBuzzOperator()
     }
 
     /**
@@ -38,7 +51,12 @@ class SampleInteractor(
      * Если айтемы в одно из флоу кончились то результирующий флоу также должен закончится
      */
     fun task3(): Flow<Pair<String, String>> {
-        return flowOf()
+        val colorsFlow = sampleRepository.produceColors()
+        val formsFlow = sampleRepository.produceForms()
+
+        return colorsFlow.zip(formsFlow) { firstData, secondData ->
+            firstData to secondData
+        }
     }
 
     /**
@@ -48,6 +66,38 @@ class SampleInteractor(
      * При любом исходе, будь то выброс исключения или успешная отработка функции вызовите метод dotsRepository.completed()
      */
     fun task4(): Flow<Int> {
-        return flowOf()
+        val defaultValue = -1
+
+        return sampleRepository.produceNumbers()
+            .catch { exception ->
+                if (exception is IllegalArgumentException) {
+                    emit(defaultValue)
+                } else {
+                    throw exception
+                }
+            }
+            .onCompletion {
+                sampleRepository.completed()
+            }
+    }
+
+    private fun Flow<Int>.fizzBuzzOperator(): Flow<String> = transform { value ->
+        val fizz = "Fizz"
+        val buzz = "Buzz"
+        val fizzBuzz = "$fizz$buzz"
+
+        emit(value.toString())
+
+        when {
+            value % 15 == 0 -> {
+                emit(fizzBuzz)
+            }
+            value % 3 == 0 -> {
+                emit(fizz)
+            }
+            value % 5 == 0 -> {
+                emit(buzz)
+            }
+        }
     }
 }

operators/src/test/java/otus/homework/flow/SampleInteractorTest.kt

@@ -125,7 +125,6 @@ class SampleInteractorTest {
             runBlockingTest {
                 dotsInteractor.task4().toList()
             }
-
         }
         verify(exactly = 1) { dotsRepository.completed() }
     }