Flow homework

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

@@ -1,7 +1,9 @@
 package otus.homework.flowcats
 
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 
 class CatsRepository(
     private val catsService: CatsService,
@@ -14,5 +16,5 @@ class CatsRepository(
             emit(latestNews)
             delay(refreshIntervalMs)
         }
-    }
+    }.flowOn(Dispatchers.IO)
 }

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

@@ -4,6 +4,6 @@ import retrofit2.http.GET
 
 interface CatsService {
 
-    @GET("random?animal_type=cat")
+    @GET("fact")
     suspend fun getCatFact(): Fact
 }

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(
@@ -11,12 +12,23 @@ class CatsView @JvmOverloads constructor(
     defStyleAttr: Int = 0
 ) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
 
+    override fun load() {
+        findViewById<TextView>(R.id.fact_textView).text = context.getText(R.string.loading)
+    }
+
     override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.text
+        findViewById<TextView>(R.id.fact_textView).text = fact.fact
+    }
+
+    override fun showError(message: String?) {
+        Toast.makeText(context, message ?: context.getText(R.string.error), Toast.LENGTH_LONG)
+            .show()
     }
 }
 
 interface ICatsView {
 
+    fun load()
     fun populate(fact: Fact)
+    fun showError(message: String?)
 }

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

@@ -2,30 +2,37 @@ package otus.homework.flowcats
 
 import androidx.lifecycle.*
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
 class CatsViewModel(
-    private val catsRepository: CatsRepository
+    catsRepository: CatsRepository
 ) : ViewModel() {
 
-    private val _catsLiveData = MutableLiveData<Fact>()
-    val catsLiveData: LiveData<Fact> = _catsLiveData
+    private val _catsFlow = MutableStateFlow<Result>(Result.Progress)
+    val catsFlow = _catsFlow.asStateFlow()
 
     init {
-        viewModelScope.launch {
-            withContext(Dispatchers.IO) {
-                catsRepository.listenForCatFacts().collect {
-                    _catsLiveData.value = it
-                }
-            }
-        }
+        catsRepository.listenForCatFacts()
+            .onEach { _catsFlow.value = Result.Success(it) }
+            .catch { _catsFlow.value = Result.Error(it.message) }
+            .launchIn(viewModelScope)
     }
 }
 
-class CatsViewModelFactory(private val catsRepository: CatsRepository) :
-    ViewModelProvider.NewInstanceFactory() {
-    override fun <T : ViewModel?> create(modelClass: Class<T>): T =
-        CatsViewModel(catsRepository) as T
+class CatsViewModelFactory(private val catsRepository: CatsRepository) : ViewModelProvider.Factory {
+    override fun <T : ViewModel> create(modelClass: Class<T>): T =
+        modelClass.getConstructor(CatsRepository::class.java).newInstance(catsRepository)
+}
+
+sealed class Result {
+    data object Progress : Result()
+    data class Success(val fact: Fact) : Result()
+    data class Error(val message: String?) : Result()
 }

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

@@ -7,7 +7,7 @@ class DiContainer {
 
     private val retrofit by lazy {
         Retrofit.Builder()
-            .baseUrl("https://cat-fact.herokuapp.com/facts/")
+            .baseUrl("https://catfact.ninja/")
             .addConverterFactory(GsonConverterFactory.create())
             .build()
     }

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

@@ -3,22 +3,8 @@ package otus.homework.flowcats
 import com.google.gson.annotations.SerializedName
 
 data class Fact(
-	@field:SerializedName("createdAt")
-	val createdAt: String,
-	@field:SerializedName("deleted")
-	val deleted: Boolean,
-	@field:SerializedName("_id")
-	val id: String,
-	@field:SerializedName("text")
-	val text: String,
-	@field:SerializedName("source")
-	val source: String,
-	@field:SerializedName("used")
-	val used: Boolean,
-	@field:SerializedName("type")
-	val type: String,
-	@field:SerializedName("user")
-	val user: String,
-	@field:SerializedName("updatedAt")
-	val updatedAt: String
+	@field:SerializedName("fact")
+	val fact: String,
+	@field:SerializedName("length")
+	val length: Int
 )

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.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 
 class MainActivity : AppCompatActivity() {
 
@@ -14,8 +17,12 @@ class MainActivity : AppCompatActivity() {
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsViewModel.catsLiveData.observe(this){
-            view.populate(it)
-        }
+        catsViewModel.catsFlow.onEach {
+            when (it) {
+                is Result.Progress -> view.load()
+                is Result.Success -> view.populate(it.fact)
+                is Result.Error -> view.showError(it.message)
+            }
+        }.launchIn(lifecycleScope)
     }
 }

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

@@ -1,3 +1,5 @@
 <resources>
     <string name="app_name">Flow cats</string>
+    <string name="error">Error!!</string>
+    <string name="loading">Please wait</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.toString())
+                when {
+                    it % 15 == 0 -> emit("FizzBuzz")
+                    it % 5 == 0 -> emit("Buzz")
+                    it % 3 == 0 -> emit("Fizz")
+                }
+            }
     }
 
     /**
@@ -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()) {
+                    f1, f2 -> f1 to f2
+            }
     }
 
     /**
@@ -48,6 +64,12 @@ 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()
+            }
     }
 }