flow homework

flowcats/build.gradle

@@ -4,15 +4,16 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
-    buildToolsVersion "30.0.3"
+    compileSdkVersion 31
+    buildToolsVersion "31.0.0"
 
     namespace = "otus.homework.flowcats"
 
     defaultConfig {
         applicationId "otus.homework.flowcats"
         minSdkVersion 23
-        targetSdkVersion 30
+        //noinspection ExpiredTargetSdkVersion
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
 
@@ -48,4 +49,5 @@ dependencies {
     implementation 'androidx.activity:activity-ktx:1.2.3'
     testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
+    implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.4.0"
 }

flowcats/src/main/AndroidManifest.xml

@@ -10,7 +10,9 @@
         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

@@ -1,5 +1,6 @@
 package otus.homework.flowcats
 
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.flow
 
@@ -10,8 +11,17 @@ 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
+                e.printStackTrace()
+                // так как сервис не доступен, я хз почему приложение по задумке должно было крашится,
+                // но у меня оно крашилось из-за 503 от сервера
+                emit(Result.Error)
+            }
+
             delay(refreshIntervalMs)
         }
     }

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

@@ -2,30 +2,36 @@ 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.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 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 _catsFlow = MutableStateFlow<Result>(Result.Loading)
+    val catsFlow: StateFlow<Result> = _catsFlow.asStateFlow()
 
     init {
         viewModelScope.launch {
             withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
+                catsRepository.listenForCatFacts()
+                    .onEach {
+                        _catsFlow.emit(it)
+                    }
+                    .launchIn(viewModelScope)
             }
         }
     }
 }
 
 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

@@ -3,6 +3,11 @@ package otus.homework.flowcats
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import androidx.activity.viewModels
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
@@ -13,9 +18,17 @@ class MainActivity : AppCompatActivity() {
         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 {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                catsViewModel.catsFlow.onEach { result ->
+                    when (result) {
+                        is Result.Success -> view.populate(result.uiModel)
+                        else -> {
+                            // не было сказано в задании как обрабатывать
+                        }
+                    }
+                }
+            }
         }
     }
 }

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

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

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 +34,17 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers().transform { value ->
+            emit(value.toString())
+            val isDivisibleBy3 = value % 3 == 0
+            val isDivisibleBy5 = value % 5 == 0
+            val isDivisibleBy15 = isDivisibleBy3 && isDivisibleBy5
+            when {
+                isDivisibleBy15 -> emit("FizzBuzz")
+                isDivisibleBy3 -> emit("Fizz")
+                isDivisibleBy5 -> emit("Buzz")
+            }
+        }
     }
 
     /**
@@ -38,7 +53,10 @@ 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 +66,16 @@ 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()
+            }
     }
 }