ДЗ Flow Серазитдинов И.Р.

build.gradle

@@ -1,6 +1,6 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = "1.4.32"
+    ext.kotlin_version = "1.6.0"
     repositories {
         google()
         jcenter()

flowcats/build.gradle

@@ -4,13 +4,13 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 32
     buildToolsVersion "30.0.3"
 
     defaultConfig {
         applicationId "otus.homework.flowcats"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 32
         versionCode 1
         versionName "1.0"
 
@@ -46,4 +46,5 @@ 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:2.5.0")
 }

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

@@ -1,18 +1,23 @@
 package otus.homework.flowcats
 
+import android.util.Log
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.flow
 
 class CatsRepository(
     private val catsService: CatsService,
     private val refreshIntervalMs: Long = 5000
 ) {
 
-    fun listenForCatFacts() = flow {
+    fun listenForCatFacts() = flow<Result<Fact>> {
         while (true) {
             val latestNews = catsService.getCatFact()
-            emit(latestNews)
+            emit(Result.Success(latestNews))
             delay(refreshIntervalMs)
         }
+    }.catch { e ->
+        Log.d([email protected], "Error", e)
+        emit(Result.Error(e.message ?: "Error"))
     }
-}
+}

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 +15,15 @@ class CatsView @JvmOverloads constructor(
     override fun populate(fact: Fact) {
         findViewById<TextView>(R.id.fact_textView).text = fact.text
     }
+
+    override fun error(message: String) {
+        Toast.makeText(context, message, Toast.LENGTH_LONG).show()
+    }
 }
 
 interface ICatsView {
 
     fun populate(fact: Fact)
+
+    fun error(message: String)
 }

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

@@ -1,7 +1,11 @@
 package otus.homework.flowcats
 
-import androidx.lifecycle.*
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -10,22 +14,25 @@ class CatsViewModel(
     private val catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _catsStateFlow = MutableStateFlow<Result<Fact>?>(null)
+    val catsStateFlow: StateFlow<Result<Fact>?> = _catsStateFlow
 
     init {
         viewModelScope.launch {
             withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
+                catsRepository.listenForCatFacts()
+                    .collect {
+                        _catsStateFlow.emit(it)
+                    }
             }
         }
     }
 }
 
 class CatsViewModelFactory(private val catsRepository: CatsRepository) :
     ViewModelProvider.NewInstanceFactory() {
-    override fun <T : ViewModel?> create(modelClass: Class<T>): T =
-        CatsViewModel(catsRepository) as T
+
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        return CatsViewModel(catsRepository) as T
+    }
 }

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

@@ -1,8 +1,12 @@
 package otus.homework.flowcats
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+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.launch {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                catsViewModel.catsStateFlow.collect {
+                    when (it) {
+                        is Result.Success -> view.populate(it.data)
+                        is Result.Error -> view.error(it.message)
+                        null -> return@collect
+                    }
+                }
+            }
         }
     }
 }

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

@@ -0,0 +1,12 @@
+package otus.homework.flowcats
+
+sealed class Result<T> {
+
+    data class Success<T>(
+        val data: T
+    ) : Result<T>()
+
+    data class Error<T>(
+        val message: String
+    ) : Result<T>()
+}

operators/build.gradle

@@ -4,12 +4,12 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 32
     buildToolsVersion "30.0.3"
     defaultConfig {
 
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 32
         versionCode 1
         versionName "1.0"
     }

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 }
+            .filterNot { it <= 20 }
+            .filterNot { it % 2 == 0 }
+            .map { "$it won" }
+            .take(3)
     }
 
     /**
@@ -29,16 +34,40 @@ class SampleInteractor(
      * Если число не делится на 3,5,15 - эмитим само число
      */
     fun task2(): Flow<String> {
-        return flowOf()
+        return sampleRepository.produceNumbers()
+            .transform { value ->
+                when {
+                    value isDividedBy 15 -> {
+                        emit(value.toString())
+                        emit("FizzBuzz")
+                    }
+                    value isDividedBy 3 -> {
+                        emit(value.toString())
+                        emit("Fizz")
+                    }
+                    value isDividedBy 5 -> {
+                        emit(value.toString())
+                        emit("Buzz")
+                    }
+                    else -> emit(value.toString())
+                }
+            }
+    }
+
+    private infix fun Int.isDividedBy(divider: Int): Boolean {
+        return this % divider == 0
     }
 
     /**
      * Реализуйте функцию task3, которая объединяет эмиты из двух flow и возвращает кортеж Pair<String,String>(f1,f2),
      * где f1 айтем из первого флоу, f2 айтем из второго флоу.
-     * Если айтемы в одно из флоу кончились то результирующий флоу также должен закончится
+     * Если айтемы в одном из флоу кончились, то результирующий флоу также должен закончиться
      */
     fun task3(): Flow<Pair<String, String>> {
-        return flowOf()
+        return sampleRepository.produceColors()
+            .zip(sampleRepository.produceForms()) { i, j ->
+                i to j
+            }
     }
 
     /**
@@ -48,6 +77,14 @@ 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()
+            }
     }
 }