Otus-Android · malinaalina · Jan 25, 2026
diff --git a/flowcats/src/main/java/otus/homework/flowcats/CatsRepository.kt b/flowcats/src/main/java/otus/homework/flowcats/CatsRepository.kt
@@ -1,7 +1,10 @@
 package otus.homework.flowcats
 
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlin.coroutines.cancellation.CancellationException
 
 class CatsRepository(
     private val catsService: CatsService,
@@ -10,9 +13,15 @@ class CatsRepository(
 
     fun listenForCatFacts() = flow {
         while (true) {
-            val latestNews = catsService.getCatFact()
-            emit(latestNews)
+            try {
+                val latestNews = catsService.getCatFact()
+                emit(Result.Success(latestNews))
+            } catch (e: Exception) {
+                if (e is CancellationException) throw e
+                emit(Result.Error(e.message.orEmpty()))
+            }
             delay(refreshIntervalMs)
         }
     }
+        .flowOn(Dispatchers.IO)
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/CatsView.kt b/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(
@@ -14,9 +15,16 @@ class CatsView @JvmOverloads constructor(
     override fun populate(fact: Fact) {
         findViewById<TextView>(R.id.fact_textView).text = fact.text
     }
+
+    override fun showToast(text: String) {
+        if (text.isNotEmpty()) {
+            Toast.makeText(context, text, Toast.LENGTH_SHORT).show()
+        }
+    }
 }
 
 interface ICatsView {
 
     fun populate(fact: Fact)
+    fun showToast(text: String)
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/CatsViewModel.kt b/flowcats/src/main/java/otus/homework/flowcats/CatsViewModel.kt
@@ -1,31 +1,30 @@
 package otus.homework.flowcats
 
 import androidx.lifecycle.*
-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
 
 class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _state = MutableStateFlow<Result<Fact>>(Result.None)
+    internal val state: StateFlow<Result<Fact>> = _state.asStateFlow()
 
     init {
         viewModelScope.launch {
-            withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
+            catsRepository.listenForCatFacts().collect {
+                _state.value = it
             }
         }
     }
 }
 
 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
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/MainActivity.kt b/flowcats/src/main/java/otus/homework/flowcats/MainActivity.kt
@@ -3,19 +3,44 @@ package otus.homework.flowcats
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import androidx.activity.viewModels
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.Job
+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) }
 
+    private var job: Job? = null
+    private lateinit var view: CatsView
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
+        view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
+    }
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
+    override fun onStart() {
+        super.onStart()
+        job = lifecycleScope.launch {
+            catsViewModel.state.collect { result ->
+                when (result) {
+                    is Result.Success<Fact> -> {
+                        view.populate(result.data)
+                    }
+                    is Result.Error -> {
+                        view.showToast(result.errorMsg)
+                    }
+                    else -> {}
+                }
+            }
         }
     }
+
+    override fun onStop() {
+        super.onStop()
+        job?.cancel()
+    }
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/Result.kt b/flowcats/src/main/java/otus/homework/flowcats/Result.kt
@@ -0,0 +1,7 @@
+package otus.homework.flowcats
+
+sealed class Result<out T> {
+    object None: Result<Nothing>()
+    data class Success<out T>(val data: T) : Result<T>()
+    data class Error(val errorMsg: String) : Result<Nothing>()
+}
diff --git a/operators/src/main/java/otus/homework/flow/SampleInteractor.kt b/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 }
+            .filter { it > 20 }
+            .filter { it % 2 != 0 }
+            .map { "$it won" }
+            .take(3)
     }
 
     /**
@@ -29,7 +34,24 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .transform {
+                when {
+                    it % 15 == 0 -> {
+                        emit(it.toString())
+                        emit("FizzBuzz")
+                    }
+                    it % 5 == 0 -> {
+                        emit(it.toString())
+                        emit("Buzz")
+                    }
+                    it % 3 == 0 -> {
+                        emit(it.toString())
+                        emit("Fizz")
+                    }
+                    else -> emit(it.toString())
+                }
+            }
     }
 
     /**
@@ -38,7 +60,10 @@ 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 +73,15 @@ 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 { e ->
+                when (e) {
+                    is IllegalArgumentException -> emit(-1)
+                    else -> throw e
+                }
+            }
+            .onCompletion {
+                sampleRepository.completed()
+            }
     }
 }