Otus-Android · alexanderbatrakov · Apr 21, 2026
diff --git a/flowcats/src/main/java/otus/homework/flowcats/CatsView.kt b/flowcats/src/main/java/otus/homework/flowcats/CatsView.kt
@@ -2,21 +2,38 @@ package otus.homework.flowcats
 
 import android.content.Context
 import android.util.AttributeSet
+import android.view.View
+import android.widget.FrameLayout
 import android.widget.TextView
-import androidx.constraintlayout.widget.ConstraintLayout
 
 class CatsView @JvmOverloads constructor(
     context: Context,
     attrs: AttributeSet? = null,
     defStyleAttr: Int = 0
-) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
+) : FrameLayout(context, attrs, defStyleAttr) {
 
-    override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.text
-    }
-}
+    private val factTextView: TextView by lazy { findViewById(R.id.fact_textView) }
+    private val progressBar: View by lazy { findViewById(R.id.progressBar) }
+
+    fun render(result: Result) {
+        when (result) {
 
-interface ICatsView {
+            is Result.Loading -> {
+                progressBar.visibility = VISIBLE
+                factTextView.visibility = GONE
+            }
 
-    fun populate(fact: Fact)
+            is Result.Success -> {
+                progressBar.visibility = GONE
+                factTextView.visibility = VISIBLE
+                factTextView.text = result.fact.text
+            }
+
+            is Result.Error -> {
+                progressBar.visibility = GONE
+                factTextView.visibility = VISIBLE
+                factTextView.text = context.getString(R.string.error_text)
+            }
+        }
+    }
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/CatsViewModel.kt b/flowcats/src/main/java/otus/homework/flowcats/CatsViewModel.kt
@@ -1,31 +1,35 @@
 package otus.homework.flowcats
 
+import android.util.Log
 import androidx.lifecycle.*
-import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
 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 _catsStateFlowData = MutableStateFlow<Result>(Result.Loading)
+    val catsStateFlowData: StateFlow<Result> = _catsStateFlowData
 
     init {
         viewModelScope.launch {
-            withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
+            catsRepository.listenForCatFacts().catch { e ->
+                _catsStateFlowData.value = Result.Error(e)
+                Log.e("ApiError", e.toString())
             }
+                .collect {
+                    _catsStateFlowData.value = Result.Success(fact = 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
@@ -3,6 +3,9 @@ package otus.homework.flowcats
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import androidx.activity.viewModels
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.flow.collect
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,8 +17,10 @@ class MainActivity : AppCompatActivity() {
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
+        lifecycleScope.launch {
+            catsViewModel.catsStateFlowData.collect {result ->
+                view.render(result)
+            }
         }
     }
 }
diff --git a/flowcats/src/main/java/otus/homework/flowcats/Result.kt b/flowcats/src/main/java/otus/homework/flowcats/Result.kt
@@ -0,0 +1,9 @@
+package otus.homework.flowcats
+
+sealed class Result {
+    data class Success(val fact: Fact) : Result()
+
+    data class Error(val e: Throwable) : Result()
+
+    object Loading : Result()
+}
diff --git a/flowcats/src/main/res/layout/activity_main.xml b/flowcats/src/main/res/layout/activity_main.xml
@@ -13,9 +13,15 @@
         android:layout_height="wrap_content"
         android:textColor="@color/black"
         android:textSize="24sp"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        android:visibility="gone"
+        android:layout_gravity="center"
+        />
+
+    <ProgressBar
+        android:id="@+id/progressBar"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:visibility="gone"/>
 
 </otus.homework.flowcats.CatsView>
diff --git a/flowcats/src/main/res/values/strings.xml b/flowcats/src/main/res/values/strings.xml
@@ -1,3 +1,4 @@
 <resources>
     <string name="app_name">Flow cats</string>
+    <string name="error_text">Произошла ошибка, попробуйете позже</string>
 </resources>
diff --git a/operators/src/main/java/otus/homework/flow/SampleInteractor.kt b/operators/src/main/java/otus/homework/flow/SampleInteractor.kt
@@ -18,7 +18,7 @@ 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 +29,28 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .flatMapConcat {
+                flow {
+                    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 +59,11 @@ class SampleInteractor(
      * Если айтемы в одно из флоу кончились то результирующий флоу также должен закончится
      */
     fun task3(): Flow<Pair<String, String>> {
-        return flowOf()
+        val a = sampleRepository.produceColors()
+        val b = sampleRepository.produceForms()
+        return a.zip(b) {
+                a,b -> Pair(a,b)
+        }
     }
 
     /**
@@ -48,6 +73,10 @@ 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().onStart({ sampleRepository.completed() }).catch { e ->
+            if (e is IllegalArgumentException) {
+                emit(-1)
+            } else throw e
+        }
     }
 }