Otus-Android#3 Реализовано решение ViewModel

Author: firkatdavletov

app/build.gradle

@@ -41,4 +41,5 @@ 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"
 }

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

@@ -15,12 +15,12 @@ class CatsView @JvmOverloads constructor(
     defStyleAttr: Int = 0
 ) : ConstraintLayout(context, attrs, defStyleAttr), ICatsView {
 
-    var presenter :CatsPresenter? = null
+    var viewModel : CatsViewModel? = null
 
     override fun onFinishInflate() {
         super.onFinishInflate()
         findViewById<Button>(R.id.button).setOnClickListener {
-            presenter?.onInitComplete()
+            viewModel?.onInitComplete()
         }
     }
 

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

@@ -0,0 +1,49 @@
+package otus.homework.coroutines
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.net.SocketTimeoutException
+
+class CatsViewModel(
+    private val catsService: CatsService,
+    private val imageService: ImageService
+): ViewModel() {
+    private var _catsView: ICatsView? = null
+    private var job: Job? = null
+
+    fun onInitComplete() {
+        job = viewModelScope.launch {
+            try {
+                val fact = catsService.getCatFact()
+                val image = imageService.getRandomImage()
+                val model = FactPresentationModel(fact, image.first())
+                withContext(Dispatchers.Main) {
+                    _catsView?.populate(model)
+                }
+            } catch (e: Exception) {
+                when (e) {
+                    is SocketTimeoutException -> {
+                        _catsView?.onError(R.string.connection_error_message)
+                    }
+                    else -> {
+                        CrashMonitor.trackWarning()
+                    }
+                }
+            }
+        }
+    }
+
+    fun attachView(catsView: ICatsView) {
+        _catsView = catsView
+    }
+
+    fun detachView() {
+        job?.cancel()
+        _catsView = null
+    }
+}

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

@@ -0,0 +1,13 @@
+package otus.homework.coroutines
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+
+class CatsViewModelFactory(
+    private val catsService: CatsService,
+    private val imageService: ImageService
+) : ViewModelProvider.NewInstanceFactory() {
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        return CatsViewModel(catsService, imageService) as T
+    }
+}

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

@@ -2,10 +2,12 @@ package otus.homework.coroutines
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.lifecycle.ViewModelProvider
 
 class MainActivity : AppCompatActivity() {
 
-    lateinit var catsPresenter: CatsPresenter
+    //lateinit var catsPresenter: CatsPresenter
+    lateinit var viewModel: CatsViewModel
 
     private val diContainer = DiContainer()
 
@@ -14,16 +16,16 @@ class MainActivity : AppCompatActivity() {
 
         val view = layoutInflater.inflate(R.layout.activity_main, null) as CatsView
         setContentView(view)
-
-        catsPresenter = CatsPresenter(diContainer.service, diContainer.imageService)
-        view.presenter = catsPresenter
-        catsPresenter.attachView(view)
-        catsPresenter.onInitComplete()
+        viewModel = CatsViewModelFactory(diContainer.service, diContainer.imageService)
+            .create(CatsViewModel::class.java)
+        view.viewModel = viewModel
+        viewModel.attachView(view)
+        viewModel.onInitComplete()
     }
 
     override fun onStop() {
         if (isFinishing) {
-            catsPresenter.detachView()
+            viewModel.detachView()
         }
         super.onStop()
     }