Домашнее задание #3 Flow

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

@@ -1,7 +1,9 @@
 package otus.homework.flowcats
 
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.onStart
 
 class CatsRepository(
     private val catsService: CatsService,
@@ -11,8 +13,19 @@ class CatsRepository(
     fun listenForCatFacts() = flow {
         while (true) {
             val latestNews = catsService.getCatFact()
-            emit(latestNews)
+            if (latestNews.isSuccessful && latestNews.body() != null)
+                emit(Result.Success(latestNews.body()!!))
+            else emit(Result.Error(latestNews.message()))
             delay(refreshIntervalMs)
         }
-    }
+    }.onStart {
+        emit(Result.Loading)
+    }.catch { error ->
+            emit(
+                Result.Error(
+                    error.message ?: error.localizedMessage
+                    ?: "Непредвиденная ошибка. Обратитесь к разработчикам"
+                )
+            )
+        }
 }

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

@@ -1,9 +1,10 @@
 package otus.homework.flowcats
 
 import retrofit2.http.GET
+import retrofit2.Response
 
 interface CatsService {
 
-    @GET("random?animal_type=cat")
-    suspend fun getCatFact(): Fact
+    @GET("fact")
+    suspend fun getCatFact(): Response<Fact>
 }

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

@@ -12,7 +12,7 @@ class CatsView @JvmOverloads constructor(
 ) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
 
     override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.text
+        findViewById<TextView>(R.id.fact_textView).text = fact.fact
     }
 }
 

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

@@ -1,7 +1,12 @@
 package otus.homework.flowcats
 
-import androidx.lifecycle.*
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -10,8 +15,8 @@ class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _catsLiveData: MutableStateFlow<Result?> = MutableStateFlow(null)
+    val catsLiveData: StateFlow<Result?> = _catsLiveData.asStateFlow()
 
     init {
         viewModelScope.launch {
@@ -26,6 +31,6 @@ class CatsViewModel(
 
 class CatsViewModelFactory(private val catsRepository: CatsRepository) :
     ViewModelProvider.NewInstanceFactory() {
-    override fun <T : ViewModel?> create(modelClass: Class<T>): T =
+    override fun <T : ViewModel> create(modelClass: Class<T>): T =
         CatsViewModel(catsRepository) as T
 }

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

@@ -7,7 +7,7 @@ class DiContainer {
 
     private val retrofit by lazy {
         Retrofit.Builder()
-            .baseUrl("https://cat-fact.herokuapp.com/facts/")
+            .baseUrl("https://catfact.ninja/")
             .addConverterFactory(GsonConverterFactory.create())
             .build()
     }

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

@@ -3,22 +3,8 @@ package otus.homework.flowcats
 import com.google.gson.annotations.SerializedName
 
 data class Fact(
-	@field:SerializedName("createdAt")
-	val createdAt: String,
-	@field:SerializedName("deleted")
-	val deleted: Boolean,
-	@field:SerializedName("_id")
-	val id: String,
-	@field:SerializedName("text")
-	val text: String,
-	@field:SerializedName("source")
-	val source: String,
-	@field:SerializedName("used")
-	val used: Boolean,
-	@field:SerializedName("type")
-	val type: String,
-	@field:SerializedName("user")
-	val user: String,
-	@field:SerializedName("updatedAt")
-	val updatedAt: String
+	@field:SerializedName("fact")
+	val fact: String,
+	@field:SerializedName("length")
+	val length: Int
 )

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

@@ -1,21 +1,42 @@
 package otus.homework.flowcats
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.widget.ProgressBar
+import android.widget.Toast
 import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.core.view.isVisible
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.InternalCoroutinesApi
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
     private val diContainer = DiContainer()
     private val catsViewModel by viewModels<CatsViewModel> { CatsViewModelFactory(diContainer.repository) }
 
+    @OptIn(InternalCoroutinesApi::class)
     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)
+        lifecycleScope.launch {
+            catsViewModel.catsLiveData.collect {
+                view.findViewById<ProgressBar>(R.id.progressBar).isVisible = it is Result.Loading
+                when (it) {
+                    is Result.Success -> {
+                        view.populate(it.fact)
+                    }
+
+                    is Result.Error -> {
+                        Toast.makeText(this@MainActivity, it.message, Toast.LENGTH_LONG).show()
+                    }
+
+                    else -> {}
+                }
+            }
         }
     }
 }

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

@@ -0,0 +1,7 @@
+package otus.homework.flowcats
+
+sealed class Result {
+    data class Error(val message: String) : Result()
+    data class Success(val fact: Fact) : Result()
+    object Loading : Result()
+}

flowcats/src/main/res/layout/activity_main.xml

@@ -18,4 +18,15 @@
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <ProgressBar
+        android:id="@+id/progressBar"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:indeterminateTint="@color/purple_500"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
 </otus.homework.flowcats.CatsView>

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

@@ -1,7 +1,15 @@
 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.collect
+import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onCompletion
+import kotlinx.coroutines.flow.take
+import kotlinx.coroutines.flow.zip
 
 @ExperimentalCoroutinesApi
 class SampleInteractor(
@@ -18,7 +26,13 @@ class SampleInteractor(
      * 6) возвращает результат
      */
     fun task1(): Flow<String> {
-        return flowOf()
+        val flow = sampleRepository.produceNumbers()
+            .map { it * 5 }
+            .filter { it > 20 }
+            .filter { it % 2 == 1 }
+            .map { number -> "$number won" }
+            .take(3)
+        return flow
     }
 
     /**
@@ -28,8 +42,15 @@ class SampleInteractor(
      * Если входное число делится на 15 - эмитим само число и после него эмитим строку FizzBuzz
      * Если число не делится на 3,5,15 - эмитим само число
      */
-    fun task2(): Flow<String> {
-        return flowOf()
+    fun task2(): Flow<String> = flow {
+        sampleRepository.produceNumbers().collect { number ->
+            emit("$number")
+            when {
+                number % 15 == 0 -> emit("FizzBuzz")
+                number % 5 == 0 -> emit("Buzz")
+                number % 3 == 0 -> emit("Fizz")
+            }
+        }
     }
 
     /**
@@ -38,7 +59,12 @@ class SampleInteractor(
      * Если айтемы в одно из флоу кончились то результирующий флоу также должен закончится
      */
     fun task3(): Flow<Pair<String, String>> {
-        return flowOf()
+        val colors = sampleRepository.produceColors()
+        val forms = sampleRepository.produceForms()
+        val zipped = colors.zip(forms) { color, form ->
+            Pair(color, form)
+        }
+        return zipped
     }
 
     /**
@@ -47,7 +73,14 @@ class SampleInteractor(
      * Если тип эксепшена != IllegalArgumentException, пробросьте его дальше
      * При любом исходе, будь то выброс исключения или успешная отработка функции вызовите метод dotsRepository.completed()
      */
-    fun task4(): Flow<Int> {
-        return flowOf()
+    fun task4(): Flow<Int> = flow {
+        sampleRepository.produceNumbers().collect { number ->
+            emit(number)
+        }
+    }.onCompletion {
+        sampleRepository.completed()
+    }.catch { error ->
+        if (error is IllegalArgumentException) emit(-1)
+        else throw error
     }
 }

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

@@ -1,14 +1,17 @@
 package otus.homework.flow
 
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flowOf
 
 interface SampleRepository {
 
-    fun produceNumbers(): Flow<Int>
+    fun produceNumbers(): Flow<Int> = flowOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
 
-    fun produceColors(): Flow<String>
+    fun produceColors(): Flow<String> =
+        flowOf("Red", "Orange", "Yellow", "Green", "Blue", "Violet", "Black", "White", "Gray")
 
-    fun produceForms(): Flow<String>
+    fun produceForms(): Flow<String> =
+        flowOf("Triangle", "Circle", "Square", "Rectangle", "Oval", "Rhombus")
 
     fun completed()
 }