Aleksei Vinogradov - Coroutines

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:2.8.3'
+    implementation 'androidx.fragment:fragment-ktx:1.8.1'
 }

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

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

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

@@ -1,10 +1,9 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
 import retrofit2.http.GET
 
-interface CatsService {
+interface CatFactService {
 
     @GET("fact")
-    fun getCatFact() : Call<Fact>
+    suspend fun getCatFact(): FactResponse
 }

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

@@ -0,0 +1,9 @@
+package otus.homework.coroutines
+
+import retrofit2.http.GET
+
+interface CatImageService {
+
+    @GET("images/search")
+    suspend fun getCatImage(): List<ImageResponse>
+}

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

@@ -0,0 +1,19 @@
+package otus.homework.coroutines
+
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.CoroutineName
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * Вынесено отдельно, так как используется, как в презентере, так и во ViewModel
+ */
+
+fun getCoroutineContext(): CoroutineContext = getCatsExceptionHandler() + getCatsCoroutineName()
+
+fun getCatsExceptionHandler() =
+    CoroutineExceptionHandler { _, e ->
+        CrashMonitor.trackWarning(e)
+    }
+
+fun getCatsCoroutineName() =
+    CoroutineName("CatsCoroutine")

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

@@ -1,28 +1,65 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import java.net.SocketTimeoutException
+
+private const val PRESENTER_CAT_JOB_KEY = "CatJob"
 
 class CatsPresenter(
-    private val catsService: CatsService
+    private val catFactService: CatFactService,
+    private val catImageService: CatImageService,
+    private val scope: CoroutineScope = PresenterScope(),
+    private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
+    private val isDataLoadedCallbaсk: (Boolean) -> Unit
 ) {
 
     private var _catsView: ICatsView? = null
 
     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()!!)
-                }
+        scope.launch {
+            val factResponseDeffered = scope.async(ioDispatcher) {
+                catFactService.getCatFact()
             }
+            val imageResponseDeffered = scope.async(ioDispatcher) {
+                catImageService.getCatImage()
+            }
+
+            val result = try {
+                /** Тестовое пробрасывание  SocketTimeoutException для проверки */
+//                    throw SocketTimeoutException()
 
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                CrashMonitor.trackWarning()
+                val factResponse = factResponseDeffered.await()
+                val imageResponse = imageResponseDeffered.await()
+                val imageResponseFirstElement = imageResponse.firstOrNull()
+                    ?: return@launch
+
+                val cat = mapServerResponseToCat(
+                    factResponse = factResponse,
+                    imageResponse = imageResponseFirstElement
+                )
+
+                Result.Success<Cat>(cat)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SocketTimeoutException) {
+                Result.Error.SocketError
+            } catch (e: Throwable) {
+                CrashMonitor.trackWarning(e)
+                Result.Error.OtherError(e)
             }
-        })
+
+            /**
+             * Логика показа Тоста находится внутри View,
+             * работает в зависимости от результата
+             */
+            _catsView?.populate(result)
+            isDataLoadedCallbaсk(true)
+        }
     }
 
     fun attachView(catsView: ICatsView) {

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

@@ -2,31 +2,84 @@ package otus.homework.coroutines
 
 import android.content.Context
 import android.util.AttributeSet
+import android.util.TypedValue
 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
 
+/**
+ * Считаю, что методы во вью не нужно делать suspend.
+ * Если ответ от сервера получен, то нет смысла создавать точку приостановки в данных функциях,
+ * это лишняя генерация кода под капотом в suspend функциях.
+ */
 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
+
+    var viewModel: CatsViewModel? = null
 
     override fun onFinishInflate() {
         super.onFinishInflate()
         findViewById<Button>(R.id.button).setOnClickListener {
             presenter?.onInitComplete()
+            viewModel?.onInitComplete()
+        }
+    }
+
+    override fun populate(result: Result) {
+        when (result) {
+            is Result.Success<*> -> {
+                val cat = result.body as Cat
+                setImage(
+                    imageUrl = cat.imageUrl,
+                    imageView = findViewById<ImageView>(R.id.image)
+                )
+                findViewById<TextView>(R.id.fact_textView).text = cat.fact
+            }
+
+            Result.Error.SocketError -> {
+                val errorMessage = context.getString(R.string.no_internet_connection)
+                showToast(errorMessage)
+            }
+
+            is Result.Error.OtherError -> {
+                val errorMessage = result.e.message
+                    ?: context.getString(R.string.unknown_error)
+                showToast(errorMessage)
+            }
         }
     }
 
-    override fun populate(fact: Fact) {
-        findViewById<TextView>(R.id.fact_textView).text = fact.fact
+    private fun setImage(imageUrl: String, imageView: ImageView) {
+        val requiredSizeInPixels = dpToPixels(400F)
+        Picasso.get()
+            .load(imageUrl)
+            .resize(requiredSizeInPixels, requiredSizeInPixels)
+            .centerInside()
+            .into(imageView)
+    }
+
+    private fun dpToPixels(dp: Float): Int {
+        return TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP,
+            dp,
+            context.resources.displayMetrics
+        ).toInt()
+    }
+
+    private fun showToast(message: String) {
+        Toast.makeText(context, message, Toast.LENGTH_LONG).show()
     }
 }
 
 interface ICatsView {
 
-    fun populate(fact: Fact)
+    fun populate(result: Result)
 }

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

@@ -0,0 +1,89 @@
+package otus.homework.coroutines
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import java.net.SocketTimeoutException
+
+class CatsViewModel(
+    private val catFactService: CatFactService,
+    private val catImageService: CatImageService,
+    private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
+    private val isDataLoadedCallbaсk: (Boolean) -> Unit
+) : ViewModel() {
+
+    private var _catsView: ICatsView? = null
+    private var isLogsEnabled = true
+
+    fun onInitComplete() {
+        viewModelScope.launch(getCoroutineContext()) {
+            val factResponseDeffered =
+                viewModelScope.async(ioDispatcher) {
+                    catFactService.getCatFact()
+                }
+            val imageResponseDeffered =
+                viewModelScope.async(ioDispatcher) {
+                    catImageService.getCatImage()
+                }
+
+            val result = try {
+                /** Тестовое пробрасывание  SocketTimeoutException для проверки */
+//                    throw SocketTimeoutException()
+
+                val factResponse = factResponseDeffered.await()
+                val imageResponse = imageResponseDeffered.await()
+                val imageResponseFirstElement = imageResponse.firstOrNull()
+                    ?: return@launch
+
+                val cat = mapServerResponseToCat(
+                    factResponse = factResponse,
+                    imageResponse = imageResponseFirstElement
+                )
+
+                Result.Success<Cat>(cat)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SocketTimeoutException) {
+                Result.Error.SocketError
+            } catch (e: Throwable) {
+                CrashMonitor.trackWarning(e)
+                Result.Error.OtherError(e)
+            }
+
+            /**
+             * Логика показа Тоста находится внутри View,
+             * работает в зависимости от результата
+             */
+            _catsView?.populate(result)
+            isDataLoadedCallbaсk(true)
+        }
+    }
+
+    fun attachView(catsView: ICatsView) {
+        _catsView = catsView
+    }
+
+    fun detachView() {
+        _catsView = null
+    }
+}
+
+class CatsViewModelFactory(
+    private val catFactService: CatFactService,
+    private val catImageService: CatImageService,
+    private val isDataLoadedCallbaсk: (Boolean) -> Unit
+) :
+    ViewModelProvider.NewInstanceFactory() {
+
+    @Suppress("UNCHECKED_CAST")
+    override fun <T : ViewModel> create(modelClass: Class<T>): T = CatsViewModel(
+        catFactService = catFactService,
+        catImageService = catImageService,
+        isDataLoadedCallbaсk = isDataLoadedCallbaсk,
+    ) as T
+}

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

@@ -1,10 +1,15 @@
 package otus.homework.coroutines
 
+import android.util.Log
+
 object CrashMonitor {
 
+    private const val CRASH_MONITOR_TAG = "CoroutinesHomework: CrashMonitor"
+
     /**
      * Pretend this is Crashlytics/AppCenter
      */
-    fun trackWarning() {
+    fun trackWarning(e: Throwable) {
+        Log.d(CRASH_MONITOR_TAG, "trackWarning(): $e")
     }
 }

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

@@ -5,12 +5,28 @@ import retrofit2.converter.gson.GsonConverterFactory
 
 class DiContainer {
 
-    private val retrofit by lazy {
+    val catFactService by lazy {
+        catFactRetrofit.create(CatFactService::class.java)
+    }
+
+    val catImageService by lazy {
+        catImageRetrofit.create(CatImageService::class.java)
+    }
+
+    private val serviceBuilder by lazy {
         Retrofit.Builder()
-            .baseUrl("https://catfact.ninja/")
             .addConverterFactory(GsonConverterFactory.create())
+    }
+
+    private val catFactRetrofit by lazy {
+        serviceBuilder
+            .baseUrl("https://catfact.ninja/")
             .build()
     }
 
-    val service by lazy { retrofit.create(CatsService::class.java) }
+    private val catImageRetrofit by lazy {
+        serviceBuilder
+            .baseUrl("https://api.thecatapi.com/v1/")
+            .build()
+    }
 }

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

@@ -0,0 +1,10 @@
+package otus.homework.coroutines
+
+import com.google.gson.annotations.SerializedName
+
+data class FactResponse(
+    @field:SerializedName("fact")
+    val fact: String,
+    @field:SerializedName("length")
+    val length: Int
+)