Выполнение домашнего задания Flow

flowcats/build.gradle

@@ -4,15 +4,15 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 34
     buildToolsVersion "30.0.3"
 
     namespace = "otus.homework.flowcats"
 
     defaultConfig {
         applicationId "otus.homework.flowcats"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 34
         versionCode 1
         versionName "1.0"
 
@@ -46,6 +46,9 @@ dependencies {
     implementation 'com.squareup.picasso:picasso:2.71828'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.3'
     implementation 'androidx.activity:activity-ktx:1.2.3'
+    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
     testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
+
+    implementation 'androidx.lifecycle:lifecycle-viewmodel-android:2.8.6'
 }

flowcats/src/main/AndroidManifest.xml

@@ -10,7 +10,8 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.Flow" >
-        <activity android:name=".MainActivity">
+        <activity android:name=".MainActivity"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

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

@@ -1,7 +1,9 @@
 package otus.homework.flowcats
 
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 
 class CatsRepository(
     private val catsService: CatsService,
@@ -14,5 +16,5 @@ class CatsRepository(
             emit(latestNews)
             delay(refreshIntervalMs)
         }
-    }
+    }.flowOn(Dispatchers.IO)
 }

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

@@ -1,31 +1,39 @@
 package otus.homework.flowcats
 
 import androidx.lifecycle.*
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 
 class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _catsData = MutableStateFlow<Result>(Result.Empty)
+    val catsData: StateFlow<Result> = _catsData.asStateFlow()
 
-    init {
+    fun init() {
         viewModelScope.launch {
-            withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
+            try {
+                catsRepository.listenForCatFacts().collect { fact ->
+                    _catsData.value = Result.Success(fact)
                 }
+            } catch (e: Exception) {
+                _catsData.value = Result.Error("Error: " + e.message)
             }
         }
     }
 }
 
 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
+}
+
+sealed class Result() {
+    data class Error(val message: String) : Result()
+    data class Success<T>(val result: T) : Result()
+    object Empty : Result()
 }

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

@@ -2,7 +2,12 @@ package otus.homework.flowcats
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.widget.Toast
 import androidx.activity.viewModels
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,8 +19,33 @@ class MainActivity : AppCompatActivity() {
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
+        catsViewModel.init()
+
+        lifecycleScope.launch {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                catsViewModel.catsData.collect { result ->
+                    when (result) {
+                        is Result.Success<*> -> {
+                            val fact = result.result as Fact
+                            view.populate(fact)
+                        }
+                        is Result.Error -> {
+                            Toast.makeText(
+                                this@MainActivity,
+                                result.message,
+                                Toast.LENGTH_LONG
+                            ).show()
+                        }
+                        Result.Empty -> {
+                            Toast.makeText(
+                                this@MainActivity,
+                                "Empty Result",
+                                Toast.LENGTH_LONG
+                            ).show()
+                        }
+                    }
+                }
+            }
         }
     }
 }

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

@@ -18,7 +18,12 @@ class SampleInteractor(
      * 6) возвращает результат
      */
     fun task1(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .map { it * 5 }               // Умножаем на 5
+            .filter { it > 20 }           // Фильтруем числа > 20
+            .filter { it % 2 != 0 }       // Убираем четные числа
+            .map { "$it won" }            // Добавляем постфикс
+            .take(3)                // Берем первые 3 элемента
     }
 
     /**
@@ -29,7 +34,15 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .transform { number ->
+                emit(number.toString())
+                when {
+                    number % 15 == 0 -> emit("FizzBuzz")
+                    number % 5 == 0 -> emit("Buzz")
+                    number % 3 == 0 -> emit("Fizz")
+                }
+            }
     }
 
     /**
@@ -38,7 +51,10 @@ class SampleInteractor(
      * Если айтемы в одно из флоу кончились то результирующий флоу также должен закончится
      */
     fun task3(): Flow<Pair<String, String>> {
-        return flowOf()
+        return sampleRepository.produceColors()
+            .zip(sampleRepository.produceForms()) { color, form ->
+                Pair(color, form)
+            }
     }
 
     /**
@@ -48,6 +64,16 @@ class SampleInteractor(
      * При любом исходе, будь то выброс исключения или успешная отработка функции вызовите метод dotsRepository.completed()
      */
     fun task4(): Flow<Int> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .catch {
+                if (it is IllegalArgumentException) {
+                    emit(-1)
+                } else {
+                    throw it
+                }
+            }
+            .onCompletion {
+                sampleRepository.completed()
+            }
     }
 }