Homework

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

@@ -0,0 +1,9 @@
+package otus.homework.flowcats
+
+sealed class ApiResult<out T> {
+
+    class Success<T>(val data: T): ApiResult<T>()
+    class Error(val e: Throwable): ApiResult<Nothing>()
+
+    data object Loading: ApiResult<Nothing>()
+}

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

@@ -1,16 +1,23 @@
 package otus.homework.flowcats
 
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
 
 class CatsRepository(
     private val catsService: CatsService,
     private val refreshIntervalMs: Long = 5000
 ) {
 
-    fun listenForCatFacts() = flow {
+    fun listenForCatFacts(): Flow<ApiResult<Fact>> = flow {
         while (true) {
-            val latestNews = catsService.getCatFact()
+            emit(ApiResult.Loading)
+            val latestNews = try {
+                val fact = catsService.getCatFact()
+                ApiResult.Success(fact)
+            } catch (e: Exception){
+                ApiResult.Error(e)
+            }
             emit(latestNews)
             delay(refreshIntervalMs)
         }

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

@@ -2,6 +2,9 @@ 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
@@ -10,14 +13,14 @@ class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _catsStF = MutableStateFlow<ApiResult<Fact>>(ApiResult.Loading)
+    val catsStF: StateFlow<ApiResult<Fact>> = _catsStF.asStateFlow()
 
     init {
         viewModelScope.launch {
             withContext(Dispatchers.IO) {
                 catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
+                    _catsStF.value = it
                 }
             }
         }
@@ -26,6 +29,6 @@ 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/MainActivity.kt

@@ -2,7 +2,11 @@ package otus.homework.flowcats
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.widget.Toast
 import androidx.activity.viewModels
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,8 +18,16 @@ class MainActivity : AppCompatActivity() {
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
+        lifecycleScope.launchWhenResumed {
+            catsViewModel.catsStF.collectLatest { result ->
+                when (result) {
+                    is ApiResult.Error -> Toast.makeText(this@MainActivity, result.e.toString(), Toast.LENGTH_LONG).show()
+                    ApiResult.Loading -> {}
+                    is ApiResult.Success ->  view.populate(result.data)
+                }
+
+            }
         }
+
     }
 }

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 +34,15 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .transform {
+                emit(it.toString())
+                when {
+                    it % 15 == 0 ->{emit("FizzBuzz")}
+                    it % 5 == 0 ->{emit("Buzz")}
+                    it % 3 == 0 ->{emit("Fizz")}
+                }
+            }
     }
 
     /**
@@ -38,7 +51,9 @@ 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()){ s, s2 ->
+            s to s2
+        }
     }
 
     /**
@@ -48,6 +63,10 @@ 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()
+            .catch {
+                it.takeIf { it is IllegalArgumentException }?.let { emit(-1) } ?: run { throw it }
+            }
+            .onCompletion { sampleRepository.completed() }
     }
 }