перевод на Mvvm

app/build.gradle

@@ -50,4 +50,6 @@ dependencies {
     implementation 'com.google.code.gson:gson:2.8.6'
     implementation 'com.squareup.okhttp3:logging-interceptor:3.8.0'
     implementation "androidx.swiperefreshlayout:swiperefreshlayout:1.1.0"
+    def fragment_version = "1.2.5"
+    implementation "androidx.fragment:fragment-ktx:$fragment_version"
 }

app/src/androidTest/java/com/example/architecturebase/ExampleInstrumentedTest.kt

@@ -1,13 +1,11 @@
 package com.example.architecturebase
 
-import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.ext.junit.runners.AndroidJUnit4
-
+import androidx.test.platform.app.InstrumentationRegistry
+import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
 
-import org.junit.Assert.*
-
 /**
  * Instrumented test, which will execute on an Android device.
  *

app/src/main/AndroidManifest.xml

@@ -3,7 +3,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.example.architecturebase">
 
-    <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-permission android:name="android.permission.INTERNET" />
 
     <application
         android:allowBackup="true"

app/src/main/java/com/example/architecturebase/CallbackFromRetrofit.kt

@@ -0,0 +1,8 @@
+package com.example.architecturebase
+
+import com.example.architecturebase.network.model.Post
+
+interface CallbackFromRetrofit {
+    fun onSuccess(value: List<Post>)
+    fun onFailure(value: Throwable)
+}

app/src/main/java/com/example/architecturebase/Fragment.kt

@@ -0,0 +1,57 @@
+package com.example.architecturebase
+
+import android.os.Bundle
+import android.view.View
+import android.widget.Toast
+import androidx.fragment.app.Fragment
+import androidx.recyclerview.widget.LinearLayoutManager
+import com.example.architecturebase.adapter.MainAdapter
+import com.example.architecturebase.databinding.FragmentBinding
+
+
+class Fragment : Fragment(R.layout.fragment) {
+
+    private val mvvmModelView: MvvmContract = ViewModelMvvm()
+
+
+    private var _binding: FragmentBinding? = null
+    private val binding get() = _binding!!
+
+    private val mainAdapter = MainAdapter()
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        _binding = FragmentBinding.bind(view)
+        binding.mainRV.apply {
+            layoutManager = LinearLayoutManager(activity)
+            adapter = mainAdapter
+        }
+
+        mvvmModelView.getPosts()
+
+        binding.listSRL.isRefreshing = true
+
+        mvvmModelView.listPosts.observe(viewLifecycleOwner) {
+            mainAdapter.items = it
+            binding.listSRL.isRefreshing = false
+        }
+
+        mvvmModelView.errorMessage.observe(viewLifecycleOwner) { t -> showFailureLoadDataDialog(t) }
+
+        binding.listSRL.setOnRefreshListener {
+            mainAdapter.items = emptyList()
+            mvvmModelView.getPosts()
+        }
+    }
+
+    private fun showFailureLoadDataDialog(t: Throwable) {
+        t.printStackTrace()
+        binding.listSRL.isRefreshing = false
+        Toast.makeText(activity, t.message, Toast.LENGTH_SHORT).show()
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+}

app/src/main/java/com/example/architecturebase/IRepository.kt

@@ -0,0 +1,8 @@
+package com.example.architecturebase
+
+import com.example.architecturebase.network.IPostApi
+
+interface IRepository {
+
+    fun getData(): IPostApi
+}

app/src/main/java/com/example/architecturebase/MainActivity.kt

@@ -1,113 +1,20 @@
 package com.example.architecturebase
 
 import android.os.Bundle
-import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
-import androidx.recyclerview.widget.LinearLayoutManager
-import com.example.architecturebase.adapter.MainAdapter
-import com.example.architecturebase.databinding.ActivityMainBinding
-import com.example.architecturebase.network.IPostApi
-import com.example.architecturebase.network.model.Post
-import okhttp3.OkHttpClient
-import okhttp3.logging.HttpLoggingInterceptor
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
-import retrofit2.Retrofit
-import retrofit2.converter.gson.GsonConverterFactory
-import java.util.concurrent.TimeUnit
 
 class MainActivity : AppCompatActivity() {
 
-    companion object {
-        private const val REQUEST_TIMEOUT_SECONDS = 5L
-    }
-
-    private val binding by lazy {
-        val bind = ActivityMainBinding.inflate(layoutInflater)
-        setContentView(bind.root)
-        bind
-    }
-
-    private val mainAdapter = MainAdapter()
-
-    private val okHttpClient = OkHttpClient.Builder()
-        .addInterceptor(HttpLoggingInterceptor().apply {
-            level = HttpLoggingInterceptor.Level.BODY
-        })
-        .callTimeout(REQUEST_TIMEOUT_SECONDS, TimeUnit.SECONDS)
-        .build()
-
-    private val retrofit = Retrofit.Builder()
-        .baseUrl("https://jsonplaceholder.typicode.com")
-        .addConverterFactory(GsonConverterFactory.create())
-        .client(okHttpClient)
-        .build()
-
-    private val postApi = retrofit.create(IPostApi::class.java)
-
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-
-        binding.mainRV.apply {
-            layoutManager = LinearLayoutManager(this@MainActivity)
-            adapter = mainAdapter
-        }
-        binding.listSRL.isRefreshing = true
-        postApi.getPosts().enqueue(object : Callback<List<Post>> {
-            override fun onResponse(call: Call<List<Post>>, response: Response<List<Post>>) {
-                if (response.isSuccessful) {
-                    response.body()?.let { posts ->
-                        // logic starts
-                        val processedPosts = posts.filter {
-                            !it.title.startsWith("H")
-                        }.map {
-                            it.copy(title = it.title + "appendix")
-                        }.sortedBy {
-                            it.title
-                        }.subList(0, posts.size - 3)
-                        // logic ends
-                        mainAdapter.items = processedPosts
-                        binding.listSRL.isRefreshing = false
-                    }
-                }
-            }
-
-            override fun onFailure(call: Call<List<Post>>, t: Throwable) {
-                Toast.makeText(this@MainActivity, t.message, Toast.LENGTH_SHORT).show()
-                t.printStackTrace()
-                binding.listSRL.isRefreshing = false
+        setContentView(R.layout.activity_main)
+        val fragment = Fragment()
+        if (savedInstanceState == null) {
+            supportFragmentManager.beginTransaction().apply {
+                setReorderingAllowed(true)
+                add(R.id.fragmentContainerView, fragment)
+                commit()
             }
-        })
-
-        binding.listSRL.setOnRefreshListener {
-            mainAdapter.items = emptyList()
-
-            postApi.getPosts().enqueue(object : Callback<List<Post>> {
-                override fun onResponse(call: Call<List<Post>>, response: Response<List<Post>>) {
-                    if (response.isSuccessful) {
-                        response.body()?.let { posts ->
-                            // logic starts
-                            val processedPosts = posts.filter {
-                                !it.title.startsWith("H")
-                            }.map {
-                                it.copy(title = it.title + "appendix")
-                            }.sortedBy {
-                                it.title
-                            }.subList(0, posts.size - 3)
-                            // logic ends
-                            mainAdapter.items = processedPosts
-                            binding.listSRL.isRefreshing = false
-                        }
-                    }
-                }
-
-                override fun onFailure(call: Call<List<Post>>, t: Throwable) {
-                    Toast.makeText(this@MainActivity, t.message, Toast.LENGTH_SHORT).show()
-                    t.printStackTrace()
-                    binding.listSRL.isRefreshing = false
-                }
-            })
         }
     }
 }

app/src/main/java/com/example/architecturebase/MvvmContract.kt

@@ -0,0 +1,12 @@
+package com.example.architecturebase
+
+import androidx.lifecycle.LifecycleObserver
+import androidx.lifecycle.LiveData
+import com.example.architecturebase.network.model.Post
+
+interface MvvmContract {
+
+    val listPosts: LiveData<List<Post>>
+    val errorMessage: LiveData<Throwable>
+    fun getPosts()
+}

app/src/main/java/com/example/architecturebase/Repository.kt

@@ -0,0 +1,34 @@
+package com.example.architecturebase
+
+import com.example.architecturebase.network.IPostApi
+import okhttp3.OkHttpClient
+import okhttp3.logging.HttpLoggingInterceptor
+import retrofit2.Retrofit
+import retrofit2.converter.gson.GsonConverterFactory
+import java.util.concurrent.TimeUnit
+
+class Repository : IRepository {
+
+    private val okHttpClient = OkHttpClient.Builder()
+        .addInterceptor(HttpLoggingInterceptor().apply {
+            level = HttpLoggingInterceptor.Level.BODY
+        })
+        .callTimeout(REQUEST_TIMEOUT_SECONDS, TimeUnit.SECONDS)
+        .build()
+
+    private val retrofit = Retrofit.Builder()
+        .baseUrl("https://jsonplaceholder.typicode.com")
+        .addConverterFactory(GsonConverterFactory.create())
+        .client(okHttpClient)
+        .build()
+
+    private val postApi = retrofit.create(IPostApi::class.java)
+
+    override fun getData(): IPostApi {
+        return postApi
+    }
+
+    companion object {
+        private const val REQUEST_TIMEOUT_SECONDS = 5L
+    }
+}

app/src/main/java/com/example/architecturebase/UseCases/UseCaseGetPosts.kt

@@ -0,0 +1,39 @@
+package com.example.architecturebase.UseCases
+
+import com.example.architecturebase.CallbackFromRetrofit
+import com.example.architecturebase.IRepository
+import com.example.architecturebase.Repository
+import com.example.architecturebase.network.model.Post
+import retrofit2.Call
+import retrofit2.Callback
+import retrofit2.Response
+
+object UseCaseGetPosts {
+
+    private val repository: IRepository = Repository()
+
+    fun loadPosts(customCallback: CallbackFromRetrofit) {
+        repository.getData().getPosts().enqueue(object : Callback<List<Post>> {
+            override fun onResponse(call: Call<List<Post>>, response: Response<List<Post>>) {
+                if (response.isSuccessful) {
+                    response.body()?.let { posts ->
+                        customCallback.onSuccess(sortedPosts(posts))
+                    }
+                }
+            }
+            override fun onFailure(call: Call<List<Post>>, t: Throwable) {
+                customCallback.onFailure(t)
+            }
+        })
+    }
+
+    private fun sortedPosts(posts: List<Post>): List<Post> {
+        return posts.filter {
+            !it.title.startsWith("H")
+        }.map {
+            it.copy(title = it.title + "appendix")
+        }.sortedBy {
+            it.title
+        }.subList(0, posts.size - 3)
+    }
+}

app/src/main/java/com/example/architecturebase/ViewModelMvvm.kt

@@ -0,0 +1,25 @@
+package com.example.architecturebase
+
+import androidx.lifecycle.*
+import com.example.architecturebase.UseCases.UseCaseGetPosts
+import com.example.architecturebase.network.model.Post
+
+class ViewModelMvvm :  MvvmContract, ViewModel() {
+
+
+    override val listPosts: MutableLiveData<List<Post>> = MutableLiveData()
+
+    override val errorMessage: MutableLiveData<Throwable> = MutableLiveData()
+
+    override fun getPosts() {
+        UseCaseGetPosts.loadPosts(object : CallbackFromRetrofit {
+            override fun onSuccess(value: List<Post>) {
+                listPosts.value = value
+            }
+
+            override fun onFailure(value: Throwable) {
+                errorMessage.value = value
+            }
+        })
+    }
+}