coroutines homework

app/build.gradle

@@ -41,4 +41,6 @@ dependencies {
     implementation 'com.google.android.material:material:1.11.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
     implementation 'com.squareup.picasso:picasso:2.71828'
+    implementation("androidx.lifecycle:lifecycle-viewmodel-ktx:2.9.1")
+    implementation("androidx.fragment:fragment-ktx:1.8.8")
 }

app/src/main/java/otus/homework/coroutines/CatsPresenter.kt

@@ -1,28 +1,82 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.async
+import kotlinx.coroutines.cancelChildren
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.net.SocketTimeoutException
 
 class CatsPresenter(
     private val catsService: CatsService
 ) {
-
+    private val scope = CoroutineScope(
+        Dispatchers.Main.immediate + SupervisorJob() + CoroutineName("CatsCoroutine")
+    )
     private var _catsView: ICatsView? = null
 
+
+    /**
+     * Не понял по условию задачи, что нужно делать, если в одном из запросов ошибка,
+     * а вдругом нет и на чьи ошибки надо показывать тосты. Тут тосты показываются только на ошибки
+     * в запросе фактов, и ошибка в одном из запросов не отменяет другой
+     *
+     * Во вьюмоделе сделаю, чтоб ошибка в любом из запросов отменяет оба запроса и ошибки из любого
+     * выводятся в текстовое поле
+     */
     fun onInitComplete() {
-        catsService.getCatFact().enqueue(object : Callback<Fact> {
+        scope.coroutineContext.cancelChildren()
+        val factJob = scope.async(Dispatchers.IO) {
+            try {
+                val response = catsService.getCatFact()
+                if (response.isSuccessful) {
+                    response.body()
+                } else {
+                    null
+                }
+            } catch (e: Throwable) {
+                if (e is CancellationException) throw e
+                when (e) {
+                    is SocketTimeoutException -> {
+                        withContext(Dispatchers.Main) {
+                            _catsView?.showToast("Не удалось получить ответ от сервера")
+                        }
+                    }
 
-            override fun onResponse(call: Call<Fact>, response: Response<Fact>) {
-                if (response.isSuccessful && response.body() != null) {
-                    _catsView?.populate(response.body()!!)
+                    else -> {
+                        CrashMonitor.trackWarning()
+                        withContext(Dispatchers.Main) {
+                            _catsView?.showToast(e.message)
+                        }
+                    }
                 }
+                null
             }
+        }
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                CrashMonitor.trackWarning()
+        val imageJob = scope.async(Dispatchers.IO) {
+            try {
+                val response = catsService.getRandomImage()
+                if (response.isSuccessful) {
+                    response.body()?.firstOrNull()
+                } else {
+                    null
+                }
+            } catch (e: Throwable) {
+                if (e is CancellationException) throw e
+                null
             }
-        })
+        }
+
+        scope.launch {
+            val fact = factJob.await()
+            val image = imageJob.await()
+            _catsView?.populate(CatsUiModel(fact?.fact, image?.url))
+        }
     }
 
     fun attachView(catsView: ICatsView) {
@@ -31,5 +85,6 @@ class CatsPresenter(
 
     fun detachView() {
         _catsView = null
+        scope.coroutineContext.cancelChildren()
     }
 }

app/src/main/java/otus/homework/coroutines/CatsService.kt

@@ -1,10 +1,15 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
+import retrofit2.Response
 import retrofit2.http.GET
 
 interface CatsService {
 
     @GET("fact")
-    fun getCatFact() : Call<Fact>
+    suspend fun getCatFact(): Response<Fact>
+
+    @GET("https://api.thecatapi.com/v1/images/search")
+    suspend fun getRandomImage(): Response<List<Image>>
+
+
 }

app/src/main/java/otus/homework/coroutines/CatsUiModel.kt

@@ -0,0 +1,3 @@
+package otus.homework.coroutines
+
+data class CatsUiModel(val fact: String? = null, val image: String? = null)

app/src/main/java/otus/homework/coroutines/CatsView.kt

@@ -3,30 +3,62 @@ package otus.homework.coroutines
 import android.content.Context
 import android.util.AttributeSet
 import android.widget.Button
+import android.widget.ImageView
 import android.widget.TextView
+import android.widget.Toast
 import androidx.constraintlayout.widget.ConstraintLayout
+import com.squareup.picasso.Picasso
 
 class CatsView @JvmOverloads constructor(
     context: Context,
     attrs: AttributeSet? = null,
     defStyleAttr: Int = 0
 ) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
 
-    var presenter :CatsPresenter? = null
+    var presenter: CatsPresenter? = null
+    private lateinit var imageView: ImageView
+    private lateinit var textView: TextView
+    var onClick: (() -> Unit)? = null
 
     override fun onFinishInflate() {
         super.onFinishInflate()
         findViewById<Button>(R.id.button).setOnClickListener {
             presenter?.onInitComplete()
+            onClick?.invoke()
         }
+        imageView = findViewById(R.id.fact_imageView)
+        textView = findViewById(R.id.fact_textView)
     }
 
-    override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.fact
+    override fun populate(uiModel: CatsUiModel) {
+        textView.text = uiModel.fact
+        Picasso.get().load(uiModel.image).into(imageView)
+    }
+
+    override fun showToast(text: String?) {
+        text?.let {
+            Toast.makeText(context, text, Toast.LENGTH_SHORT).show()
+        }
+    }
+
+    fun bindError(message: String?) {
+        textView.text = message
+        imageView.setImageResource(0)
+    }
+
+    fun bindSuccess(uiModel: CatsUiModel) {
+        textView.text = uiModel.fact
+        Picasso.get().load(uiModel.image).into(imageView)
+    }
+
+    fun bindLoading() {
+        textView.text = null
+        imageView.setImageResource(0)
     }
 }
 
 interface ICatsView {
 
-    fun populate(fact: Fact)
+    fun populate(uiModel: CatsUiModel)
+    fun showToast(text: String?)
 }

app/src/main/java/otus/homework/coroutines/CatsViewModel.kt

@@ -0,0 +1,73 @@
+package otus.homework.coroutines
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.async
+import kotlinx.coroutines.cancelChildren
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import java.net.SocketTimeoutException
+
+class CatsViewModel(private val catsService: CatsService) : ViewModel() {
+    private val _uiModelFlow = MutableStateFlow<Result>(Result.Loading)
+    val uiModelFlow: StateFlow<Result> = _uiModelFlow.asStateFlow()
+    private val exceptionHandler = CoroutineExceptionHandler { _, e ->
+        when (e) {
+            is SocketTimeoutException -> {
+                _uiModelFlow.tryEmit(Result.Error(message = "Не удалось получить ответ от сервера"))
+            }
+
+            else -> {
+                CrashMonitor.trackWarning()
+                _uiModelFlow.tryEmit(Result.Error(message = e.message))
+            }
+        }
+    }
+
+    fun load() {
+        viewModelScope.coroutineContext.cancelChildren()
+        viewModelScope.launch(exceptionHandler) {
+            _uiModelFlow.emit(Result.Loading)
+            val factJob = async(Dispatchers.IO) {
+                val response = catsService.getCatFact()
+                if (response.isSuccessful) {
+                    response.body()
+                } else {
+                    null
+                }
+            }
+
+            val imageJob = async(Dispatchers.IO) {
+                val response = catsService.getRandomImage()
+                if (response.isSuccessful) {
+                    response.body()?.firstOrNull()
+                } else {
+                    null
+                }
+            }
+
+            val factResult = factJob.await()
+            val imageResult = imageJob.await()
+            _uiModelFlow.emit(
+                Result.Success(
+                    CatsUiModel(
+                        fact = factResult?.fact,
+                        image = imageResult?.url
+                    )
+                )
+            )
+        }
+    }
+
+    class Factory(private val catsService: CatsService) : ViewModelProvider.Factory {
+        @Suppress("UNCHECKED_CAST")
+        override fun <T : ViewModel> create(modelClass: Class<T>): T {
+            return CatsViewModel(catsService) as T
+        }
+    }
+}

app/src/main/java/otus/homework/coroutines/Image.kt

@@ -0,0 +1,14 @@
+package otus.homework.coroutines
+
+import com.google.gson.annotations.SerializedName
+
+data class Image(
+    @field:SerializedName("id")
+    val id: String,
+    @field:SerializedName("url")
+    val url: String,
+    @field:SerializedName("width")
+    val width: Int,
+    @field:SerializedName("height")
+    val height: Int,
+)

app/src/main/java/otus/homework/coroutines/MainActivity.kt

@@ -1,24 +1,45 @@
 package otus.homework.coroutines
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 
 class MainActivity : AppCompatActivity() {
 
     lateinit var catsPresenter: CatsPresenter
 
     private val diContainer = DiContainer()
+    private val viewModel by viewModels<CatsViewModel>(
+        factoryProducer = { CatsViewModel.Factory(diContainer.service) }
+    )
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        viewModel.load()
 
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
         catsPresenter = CatsPresenter(diContainer.service)
+
+        view.onClick = { viewModel.load() }
+        /** код для варианта с презентером
         view.presenter = catsPresenter
         catsPresenter.attachView(view)
         catsPresenter.onInitComplete()
+         */
+        viewModel.uiModelFlow
+            .onEach { result ->
+                when (result) {
+                    is Result.Error -> view.bindError(result.message)
+                    Result.Loading -> view.bindLoading()
+                    is Result.Success -> view.bindSuccess(result.uiModel)
+                }
+            }
+            .launchIn(lifecycleScope)
     }
 
     override fun onStop() {

app/src/main/java/otus/homework/coroutines/Result.kt

@@ -0,0 +1,7 @@
+package otus.homework.coroutines
+
+sealed interface Result {
+    data class Success(val uiModel: CatsUiModel) : Result
+    data class Error(val message: String?) : Result
+    object Loading : Result
+}

app/src/main/res/layout/activity_main.xml

@@ -7,6 +7,18 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
+    <ImageView
+        android:id="@+id/fact_imageView"
+        android:layout_width="200dp"
+        android:layout_height="200dp"
+        android:contentDescription="@null"
+        app:layout_constraintBottom_toTopOf="@+id/fact_textView"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_chainStyle="packed"
+        tools:background="@color/black" />
+
     <TextView
         android:id="@+id/fact_textView"
         android:textColor="@color/black"
@@ -16,7 +28,8 @@
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:layout_constraintTop_toBottomOf="@+id/fact_imageView"
+        tools:text="Some text" />
 
     <Button
         android:id="@+id/button"