Flow homework

flowcats/build.gradle

@@ -4,15 +4,15 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 34
     buildToolsVersion "30.0.3"
 
     namespace = "otus.homework.flowcats"
 
     defaultConfig {
         applicationId "otus.homework.flowcats"
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 33
         versionCode 1
         versionName "1.0"
 
@@ -36,16 +36,17 @@ android {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
-    implementation 'androidx.core:core-ktx:1.3.2'
+    implementation 'androidx.core:core-ktx:1.13.1'
     implementation 'com.squareup.retrofit2:retrofit:2.9.0'
     implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
-    implementation 'com.google.code.gson:gson:2.8.6'
-    implementation 'androidx.appcompat:appcompat:1.2.0'
-    implementation 'com.google.android.material:material:1.3.0'
-    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
+    implementation 'com.google.code.gson:gson:2.10.1'
+    implementation 'androidx.appcompat:appcompat:1.7.0'
+    implementation 'com.google.android.material:material:1.12.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
     implementation 'com.squareup.picasso:picasso:2.71828'
-    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.3'
-    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 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.1'
+    implementation 'androidx.activity:activity-ktx:1.9.1'
+    implementation 'androidx.test.ext:junit-ktx:1.2.1'
+    testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.7.1'
+    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.8.4'
 }

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 +1,24 @@
 package otus.homework.flowcats
 
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.flow
+import otus.homework.flowcats.Result
+import java.util.concurrent.TimeoutException
 
 class CatsRepository(
     private val catsService: CatsService,
     private val refreshIntervalMs: Long = 5000
 ) {
 
-    fun listenForCatFacts() = flow {
+    fun listenForCatFacts() = flow<Result> {
         while (true) {
             val latestNews = catsService.getCatFact()
-            emit(latestNews)
+            emit(Result.Success(latestNews))
             delay(refreshIntervalMs)
         }
+    }.catch {
+        println(it)
+        emit(Result.Error)
     }
 }

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

@@ -2,22 +2,23 @@ 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.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.Init)
+    val catsFlow: StateFlow<Result> = _catsFlow
 
     init {
         viewModelScope.launch {
             withContext(Dispatchers.IO) {
                 catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
+                    _catsFlow.value = it
                 }
             }
         }
@@ -26,6 +27,6 @@ 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 +2,13 @@ package otus.homework.flowcats
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.widget.Toast
 import androidx.activity.viewModels
+import androidx.core.content.ContextCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,8 +20,23 @@ 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.catsFlow.collect { result ->
+                    when (result) {
+                        is Result.Success<*> -> view.populate(result.data as Fact)
+                        is Result.Error -> {
+                            Toast.makeText(
+                                this@MainActivity,
+                                ContextCompat.getString(this@MainActivity, R.string.text_error),
+                                Toast.LENGTH_SHORT
+                            ).show()
+                        }
+
+                        else -> {}
+                    }
+                }
+            }
         }
     }
 }

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

@@ -0,0 +1,7 @@
+package otus.homework.flowcats
+
+sealed class Result {
+    class Success<out T>(val data: T) : Result()
+    data object Error : Result()
+    data object Init : Result()
+}

flowcats/src/main/res/values/strings.xml

@@ -1,3 +1,4 @@
 <resources>
     <string name="app_name">Flow cats</string>
+    <string name="text_error">Упс! Что-то пошло не так...</string>
 </resources>

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")
+                when {
+                    it % 15 == 0 -> emit("FizzBuzz")
+                    it % 3 == 0 -> emit("Fizz")
+                    it % 5 == 0 -> emit("Buzz")
+                }
+            }
     }
 
     /**
@@ -38,7 +51,10 @@ 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 +64,10 @@ 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() }
     }
-}
+}