Coroutines Homework

app/build.gradle

@@ -41,4 +41,7 @@ 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:2.7.0")
+    implementation("androidx.activity:activity-ktx:1.8.2")
 }

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

@@ -1,28 +1,47 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import java.net.SocketTimeoutException
+import kotlin.coroutines.CoroutineContext
 
 class CatsPresenter(
-    private val catsService: CatsService
+    private val catsService: CatsService,
+    private val catsImageService: CatsImageService
 ) {
 
     private var _catsView: ICatsView? = null
 
+    private val presenterScope = PresenterScope()
+
     fun onInitComplete() {
-        catsService.getCatFact().enqueue(object : Callback<Fact> {
 
-            override fun onResponse(call: Call<Fact>, response: Response<Fact>) {
-                if (response.isSuccessful && response.body() != null) {
-                    _catsView?.populate(response.body()!!)
+        presenterScope.launch {
+            try {
+                val factDeferred = async(Dispatchers.IO) {
+                    catsService.getCatFact()
+                }
+                val imageDeferred = async(Dispatchers.IO) {
+                    catsImageService.getCatImage()
                 }
-            }
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                CrashMonitor.trackWarning()
+                val fact = factDeferred.await()
+                val image = imageDeferred.await()
+
+                val presentationModel = PresentationModel(fact = fact.fact, imageUrl = image[0].url)
+                _catsView?.populate(presentationModel)
+
+            } catch (_: SocketTimeoutException) {
+                _catsView?.showToast("Не удалось получить ответ от сервера")
+            } catch (e: Exception) {
+                CrashMonitor.trackWarning(e)
+                _catsView?.showToast(e.message ?: "")
             }
-        })
+        }
     }
 
     fun attachView(catsView: ICatsView) {
@@ -32,4 +51,19 @@ class CatsPresenter(
     fun detachView() {
         _catsView = null
     }
+
+    fun cancelJob() {
+        presenterScope.cancel()
+    }
+}
+
+class PresenterScope() : CoroutineScope {
+    private val job = Job()
+
+    override val coroutineContext: CoroutineContext =
+        Dispatchers.Main + job + CoroutineName("CatsCoroutine")
+
+    fun cancel() {
+        job.cancel()
+    }
 }

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

@@ -1,10 +1,13 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
 import retrofit2.http.GET
 
 interface CatsService {
-
     @GET("fact")
-    fun getCatFact() : Call<Fact>
+    suspend fun getCatFact(): Fact
+}
+
+interface CatsImageService {
+    @GET("v1/images/search")
+    suspend fun getCatImage(): List<Image>
 }

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

@@ -3,30 +3,49 @@ 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 {
+) : ConstraintLayout(context, attrs, defStyleAttr) {
 
-    var presenter :CatsPresenter? = null
+    var viewModel: CatsViewModel? = null
 
     override fun onFinishInflate() {
         super.onFinishInflate()
         findViewById<Button>(R.id.button).setOnClickListener {
-            presenter?.onInitComplete()
+            viewModel?.onInitComplete()
         }
     }
 
-    override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.fact
+    fun populate(presentationModel: PresentationModel) {
+        findViewById<TextView>(R.id.fact_textView).text = presentationModel.fact
+        Picasso
+            .get()
+            .load(presentationModel.imageUrl)
+            .into(findViewById<ImageView>(R.id.cat_imageView))
+    }
+
+    fun showToast(message: String) {
+        Toast
+            .makeText(
+                context,
+                message,
+                Toast.LENGTH_SHORT
+            )
+            .show()
     }
 }
 
 interface ICatsView {
 
-    fun populate(fact: Fact)
+    fun populate(presentationModel: PresentationModel)
+
+    fun showToast(message: String)
 }

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

@@ -0,0 +1,66 @@
+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.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import java.net.SocketTimeoutException
+
+class CatsViewModel(
+    private val catsService: CatsService,
+    private val catsImageService: CatsImageService
+) : ViewModel() {
+
+    private val _presentationState = MutableStateFlow<Result<PresentationModel>?>(null)
+    val presentationState = _presentationState.asStateFlow()
+
+    val exceptionHandler = CoroutineExceptionHandler { _, exception ->
+        CrashMonitor.trackWarning(exception as Exception)
+        _presentationState.value = Result.Error(exception.message ?: "")
+    }
+
+    fun onInitComplete() {
+        viewModelScope.launch(exceptionHandler) {
+            try {
+                val factDeferred = async(Dispatchers.IO) {
+                    catsService.getCatFact()
+                }
+                val imageDeferred = async(Dispatchers.IO) {
+                    catsImageService.getCatImage()
+                }
+
+                val fact = factDeferred.await()
+                val image = imageDeferred.await()
+
+                _presentationState.value = Result.Success(
+                    PresentationModel(fact = fact.fact, imageUrl = image[0].url)
+                )
+
+            } catch (_: SocketTimeoutException) {
+                _presentationState.value = Result.Error(
+                    "Не удалось получить ответ от сервера"
+                )
+            }
+        }
+    }
+}
+
+class CatsViewModelFactory(
+    private val catsService: CatsService,
+    private val catsImageService: CatsImageService
+) :
+    ViewModelProvider.Factory {
+
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        @Suppress("UNCHECKED_CAST")
+        if (modelClass.isAssignableFrom(CatsViewModel::class.java)) {
+            return CatsViewModel(catsService, catsImageService) as T
+        }
+        throw IllegalArgumentException("Unknown ViewModel class")
+    }
+}

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

@@ -5,6 +5,7 @@ object CrashMonitor {
     /**
      * Pretend this is Crashlytics/AppCenter
      */
-    fun trackWarning() {
+    fun trackWarning(e: Exception) {
+        //Firebase.crashlytics.log("e")
     }
 }

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

@@ -13,4 +13,13 @@ class DiContainer {
     }
 
     val service by lazy { retrofit.create(CatsService::class.java) }
+
+    private val imageRetrofit by lazy {
+        Retrofit.Builder()
+            .baseUrl("https://api.thecatapi.com/")
+            .addConverterFactory(GsonConverterFactory.create())
+            .build()
+    }
+
+    val imageService by lazy { imageRetrofit.create(CatsImageService::class.java) }
 }

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

@@ -0,0 +1,8 @@
+package otus.homework.coroutines
+
+data class Image(
+    val id: String,
+    val url: String,
+    val width: Int,
+    val height: Int
+)

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

@@ -2,29 +2,44 @@ package otus.homework.coroutines
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.activity.viewModels
+import androidx.lifecycle.lifecycleScope
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
 
-    lateinit var catsPresenter: CatsPresenter
-
     private val diContainer = DiContainer()
 
+    private val viewModel: CatsViewModel by viewModels {
+        CatsViewModelFactory(
+            catsService = diContainer.service,
+            catsImageService = diContainer.imageService
+        )
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
 
-        catsPresenter = CatsPresenter(diContainer.service)
-        view.presenter = catsPresenter
-        catsPresenter.attachView(view)
-        catsPresenter.onInitComplete()
-    }
+        view.viewModel = viewModel
+        viewModel.onInitComplete()
+
+        lifecycleScope.launch {
+            viewModel.presentationState.collect { result ->
+                when (result) {
+                    is Result.Success -> {
+                        view.populate(result.data)
+                    }
+
+                    is Result.Error -> {
+                        view.showToast(result.message)
+                    }
 
-    override fun onStop() {
-        if (isFinishing) {
-            catsPresenter.detachView()
+                    else -> {}
+                }
+            }
         }
-        super.onStop()
     }
 }

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

@@ -0,0 +1,6 @@
+package otus.homework.coroutines
+
+data class PresentationModel(
+    val fact: String,
+    val imageUrl: String
+)

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

@@ -0,0 +1,6 @@
+package otus.homework.coroutines
+
+sealed class Result<out T> {
+    data class Success<T>(val data: T) : Result<T>()
+    data class Error(val message: String) : Result<Nothing>()
+}

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

@@ -7,22 +7,33 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
+    <ImageView
+        android:id="@+id/cat_imageView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:contentDescription="@string/cat_s_image"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintBottom_toTopOf="@id/fact_textView"/>
+
     <TextView
         android:id="@+id/fact_textView"
         android:textColor="@color/black"
         android:textSize="24sp"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintBottom_toTopOf="@id/button"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:layout_constraintTop_toBottomOf="@id/cat_imageView" />
 
     <Button
         android:id="@+id/button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/more_facts"
+        app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/fact_textView" />

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

@@ -1,4 +1,5 @@
 <resources>
     <string name="app_name">Cat Facts </string>
     <string name="more_facts">More Facts</string>
+    <string name="cat_s_image">Cat\'s image</string>
 </resources>