Petr U. HW Coroutines

app/build.gradle

@@ -8,7 +8,7 @@ android {
     compileSdkVersion 34
     defaultConfig {
         applicationId "otus.homework.coroutines"
-        minSdkVersion 23
+        minSdkVersion 24
         targetSdkVersion 34
         versionCode 1
         versionName "1.0"
@@ -33,6 +33,8 @@ android {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0'
+    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0'
     implementation 'androidx.core:core-ktx:1.12.0'
     implementation 'com.squareup.retrofit2:retrofit:2.9.0'
     implementation 'com.squareup.retrofit2:converter-gson:2.9.0'

app/src/main/AndroidManifest.xml

@@ -7,10 +7,15 @@
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
+        android:networkSecurityConfig="@xml/network_security_config"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.Coroutines">
-        <activity android:name=".MainActivity"
+        <activity
+            android:name=".MainActivity2"
+            android:exported="false" />
+        <activity
+            android:name=".MainActivity"
             android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

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

@@ -0,0 +1,10 @@
+package otus.homework.coroutines
+
+import com.google.gson.annotations.SerializedName
+
+data class CatImage(
+    @field:SerializedName("id")
+    val id: String,
+    @field:SerializedName("url")
+    val url: String,
+)

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

@@ -0,0 +1,11 @@
+package otus.homework.coroutines
+
+import retrofit2.http.GET
+
+private const val VERSION_API = "v1/"
+
+interface CatImageService {
+
+    @GET("${VERSION_API}images/search")
+    suspend fun getRandomImages(): List<CatImage>
+}

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

@@ -1,35 +1,69 @@
 package otus.homework.coroutines
 
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.net.SocketTimeoutException
+import kotlin.coroutines.cancellation.CancellationException
+
+interface ICatsPresenter {
+    fun onInitComplete()
+    fun attachView(catsView: ICatsView)
+    fun detachView()
+}
 
 class CatsPresenter(
-    private val catsService: CatsService
-) {
+    private val catsService: CatsService,
+    private val catImageService: CatImageService,
+): ICatsPresenter {
 
     private var _catsView: ICatsView? = null
+    private val presenterScope = PresenterScope(CoroutineName("CatsCoroutine"))
+    private var workJob: Job? = 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()!!)
+    override fun onInitComplete() {
+        if (workJob?.isActive == true) {
+            _catsView?.handle(R.string.cats_wait_next_fact)
+            return
+        }
+        workJob = presenterScope.launch {
+            try {
+                withContext(Dispatchers.IO) {
+                    val factDeferred = async {
+                        catsService.getCatFact()
+                    }
+                    val imageDeferred = async {
+                        catImageService.getRandomImages()
+                    }
+                    withContext(Dispatchers.Main) {
+                        _catsView?.populate(
+                            factDeferred.await(),
+                            imageDeferred.await()
+                        )
+                    }
                 }
+            } catch (timeOutException: SocketTimeoutException) {
+                _catsView?.handle(R.string.app_request_timeout)
+            } catch (_: CancellationException) {
+            } catch (t: Throwable) {
+                CrashMonitor.trackError(t)
+                _catsView?.handle(t.message.toString())
             }
-
-            override fun onFailure(call: Call<Fact>, t: Throwable) {
-                CrashMonitor.trackWarning()
-            }
-        })
+        }
     }
 
-    fun attachView(catsView: ICatsView) {
+    override fun attachView(catsView: ICatsView) {
         _catsView = catsView
     }
 
-    fun detachView() {
+    override fun detachView() {
         _catsView = null
+        CrashMonitor.trackWarning("Stop detachView")
+        presenterScope.cancel()
     }
 }

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

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

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

@@ -1,32 +1,86 @@
 package otus.homework.coroutines
 
 import android.content.Context
+import android.content.Intent
 import android.util.AttributeSet
 import android.widget.Button
+import android.widget.ImageView
 import android.widget.TextView
+import android.widget.Toast
+import androidx.annotation.StringRes
 import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.content.ContextCompat.startActivity
+import androidx.core.os.bundleOf
+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: ICatsPresenter? = null
 
     override fun onFinishInflate() {
         super.onFinishInflate()
         findViewById<Button>(R.id.button).setOnClickListener {
             presenter?.onInitComplete()
         }
+        findViewById<Button>(R.id.button2).setOnClickListener {
+            // для проверки отмены корутин
+            val switchActivityIntent = Intent(context, MainActivity2::class.java)
+            startActivity(context, switchActivityIntent, bundleOf())
+        }
     }
 
-    override fun populate(fact: Fact) {
+    override fun populate(fact: Fact, images: List<CatImage>) {
         findViewById<TextView>(R.id.fact_textView).text = fact.fact
+        images.firstOrNull()?.let {
+            Picasso.get().load(it.url).into(findViewById<ImageView>(R.id.cat_image))
+        }
     }
+
+    override fun populate(result: Result<CatData>) {
+        when (result) {
+            is Result.Success -> populate(result.data.fact, result.data.images)
+            is Result.Error -> {
+                when {
+                    result.errorResId != null -> handle(result.errorResId)
+                    result.errorMsg != null -> handle(result.errorMsg)
+                    else -> handle(R.string.app_unknown_error)
+                }
+            }
+        }
+    }
+
+    override fun handle(@StringRes resId: Int) {
+        handle(context.getString(resId))
+    }
+
+    override fun handle(msg: String) {
+        Toast.makeText(context, msg, Toast.LENGTH_LONG).show()
+    }
+}
+
+interface ICatsView : IUserMessageHandler {
+
+    fun populate(fact: Fact, images: List<CatImage>)
+
+    fun populate(result: Result<CatData>)
 }
 
-interface ICatsView {
+sealed class Result<out T> {
+
+    class Success<out T>(val data: T) : Result<T>()
+
+    class Error(
+        @StringRes val errorResId: Int? = null,
+        val errorMsg: String? = null
+    ) : Result<Nothing>()
+}
 
-    fun populate(fact: Fact)
-}
+data class CatData(
+    val fact: Fact,
+    val images: List<CatImage>,
+)

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

@@ -0,0 +1,71 @@
+package otus.homework.coroutines
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.net.SocketTimeoutException
+import kotlin.coroutines.cancellation.CancellationException
+
+class CatsViewModel(
+    private val catsService: CatsService,
+    private val catImageService: CatImageService,
+) : ViewModel(), ICatsPresenter {
+
+    private var _catsView: ICatsView? = null
+    private var workJob: Job? = null
+    private val scopeExceptionHandler = CoroutineExceptionHandler { coroutineContext, throwable ->
+        val error = when (throwable) {
+            is SocketTimeoutException -> Result.Error(errorResId = R.string.app_request_timeout)
+            is CancellationException -> null
+            else -> Result.Error(errorMsg = throwable.message.toString())
+        }
+        error?.let { e ->
+            _catsView?.populate(e)
+            CrashMonitor.trackError(
+                throwable, "Handled by VMCoroutineExceptionHandler $coroutineContext"
+            )
+        }
+    }
+
+    override fun onInitComplete() {
+        if (workJob?.isActive == true) {
+            _catsView?.handle(R.string.cats_wait_next_fact)
+            return
+        }
+        workJob = viewModelScope.launch(scopeExceptionHandler) {
+            withContext(Dispatchers.IO) {
+                val factDeferred = async {
+                    catsService.getCatFact()
+                }
+                val imageDeferred = async {
+                    catImageService.getRandomImages()
+                }
+                withContext(Dispatchers.Main) {
+                    _catsView?.populate(
+                        Result.Success(
+                            CatData(
+                                factDeferred.await(),
+                                imageDeferred.await()
+                            )
+                        )
+                    )
+                }
+            }
+        }
+    }
+
+    override fun attachView(catsView: ICatsView) {
+        _catsView = catsView
+    }
+
+    override fun detachView() {
+        _catsView = null
+        viewModelScope.cancel()
+    }
+}

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

@@ -1,10 +1,19 @@
 package otus.homework.coroutines
 
+import android.util.Log
+
 object CrashMonitor {
 
     /**
      * Pretend this is Crashlytics/AppCenter
      */
-    fun trackWarning() {
+    fun trackWarning(msg: String) {
+        Log.w(MONITOR_TAG, msg)
+    }
+
+    fun trackError(t: Throwable? = null, msg: String? = null) {
+        Log.e(MONITOR_TAG, msg, t)
     }
+
+    private const val MONITOR_TAG = "OHC_CrashMonitor"
 }

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

@@ -1,16 +1,31 @@
 package otus.homework.coroutines
 
+import okhttp3.OkHttpClient
 import retrofit2.Retrofit
 import retrofit2.converter.gson.GsonConverterFactory
+import java.util.concurrent.TimeUnit
 
 class DiContainer {
 
     private val retrofit by lazy {
         Retrofit.Builder()
             .baseUrl("https://catfact.ninja/")
+            .client(OkHttpClient.Builder().apply {
+                //для проверки работы при SocketTimeoutException
+                readTimeout(5, TimeUnit.SECONDS)
+            }.build())
+            .addConverterFactory(GsonConverterFactory.create())
+            .build()
+    }
+
+    private val retrofitImage by lazy {
+        Retrofit.Builder()
+            .baseUrl("https://api.thecatapi.com/")
             .addConverterFactory(GsonConverterFactory.create())
             .build()
     }
 
     val service by lazy { retrofit.create(CatsService::class.java) }
+
+    val imageServise by lazy { retrofitImage.create(CatImageService::class.java) }
 }

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

@@ -0,0 +1,10 @@
+package otus.homework.coroutines
+
+import androidx.annotation.StringRes
+
+interface IUserMessageHandler {
+
+    fun handle(@StringRes resId: Int)
+
+    fun handle(msg: String)
+}