Koin

app/build.gradle

@@ -33,7 +33,7 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
+    implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation "com.android.support:appcompat-v7:$android_support_version"
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
@@ -63,10 +63,8 @@ dependencies {
     implementation "com.squareup.retrofit2:adapter-rxjava2:$retrofit_version"
     implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version"
 
-    // Dagger 2
-    implementation "com.google.dagger:dagger:$dagger2_version"
-    kapt "com.google.dagger:dagger-compiler:$dagger2_version"
-    compileOnly "org.glassfish:javax.annotation:3.1.1"
+    // Koin
+    implementation "org.koin:koin-android-architecture:$koin_version"
 
     //Rx
     implementation "io.reactivex.rxjava2:rxjava:2.1.15"

app/src/main/AndroidManifest.xml

@@ -4,6 +4,7 @@
     <uses-permission android:name="android.permission.INTERNET"/>
 
     <application
+        android:name=".PostsApplication"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"

app/src/main/kotlin/net/gahfy/mvvmposts/PostsApplication.kt

@@ -0,0 +1,14 @@
+package net.gahfy.mvvmposts
+
+import android.app.Application
+import net.gahfy.mvvmposts.utils.postsModule
+import org.koin.android.ext.android.startKoin
+
+class PostsApplication : Application() {
+
+    override fun onCreate() {
+        super.onCreate()
+
+        startKoin(this, listOf(postsModule(this)))
+    }
+}

app/src/main/kotlin/net/gahfy/mvvmposts/base/BaseViewModel.kt

@@ -1,27 +1,5 @@
 package net.gahfy.mvvmposts.base
 
 import android.arch.lifecycle.ViewModel
-import net.gahfy.mvvmposts.injection.component.DaggerViewModelInjector
-import net.gahfy.mvvmposts.injection.component.ViewModelInjector
-import net.gahfy.mvvmposts.injection.module.NetworkModule
-import net.gahfy.mvvmposts.ui.post.PostListViewModel
 
-abstract class BaseViewModel:ViewModel(){
-    private val injector: ViewModelInjector = DaggerViewModelInjector
-            .builder()
-            .networkModule(NetworkModule)
-            .build()
-
-    init {
-        inject()
-    }
-
-    /**
-     * Injects the required dependencies
-     */
-    private fun inject() {
-        when (this) {
-            is PostListViewModel -> injector.inject(this)
-        }
-    }
-}
+abstract class BaseViewModel:ViewModel()

app/src/main/kotlin/net/gahfy/mvvmposts/injection/ViewModelFactory.kt

@@ -2,17 +2,16 @@ package net.gahfy.mvvmposts.injection
 
 import android.arch.lifecycle.ViewModel
 import android.arch.lifecycle.ViewModelProvider
-import android.arch.persistence.room.Room
-import android.support.v7.app.AppCompatActivity
-import net.gahfy.mvvmposts.model.database.AppDatabase
+import net.gahfy.mvvmposts.model.PostDao
+import net.gahfy.mvvmposts.network.PostApi
 import net.gahfy.mvvmposts.ui.post.PostListViewModel
 
-class ViewModelFactory(private val activity: AppCompatActivity): ViewModelProvider.Factory{
+class ViewModelFactory(private val postDao: PostDao, private val postApi: PostApi): ViewModelProvider.Factory{
+
     override fun <T : ViewModel?> create(modelClass: Class<T>): T {
         if (modelClass.isAssignableFrom(PostListViewModel::class.java)) {
-            val db = Room.databaseBuilder(activity.applicationContext, AppDatabase::class.java, "posts").build()
             @Suppress("UNCHECKED_CAST")
-            return PostListViewModel(db.postDao()) as T
+            return PostListViewModel(postDao, postApi) as T
         }
         throw IllegalArgumentException("Unknown ViewModel class")
 

app/src/main/kotlin/net/gahfy/mvvmposts/ui/post/PostListActivity.kt

@@ -1,7 +1,6 @@
 package net.gahfy.mvvmposts.ui.post
 
 import android.arch.lifecycle.Observer
-import android.arch.lifecycle.ViewModelProviders
 import android.databinding.DataBindingUtil
 import android.os.Bundle
 import android.support.annotation.StringRes
@@ -10,11 +9,11 @@ import android.support.v7.app.AppCompatActivity
 import android.support.v7.widget.LinearLayoutManager
 import net.gahfy.mvvmposts.R
 import net.gahfy.mvvmposts.databinding.ActivityPostListBinding
-import net.gahfy.mvvmposts.injection.ViewModelFactory
+import org.koin.android.architecture.ext.viewModel
 
 class PostListActivity: AppCompatActivity() {
     private lateinit var binding: ActivityPostListBinding
-    private lateinit var viewModel: PostListViewModel
+    private val viewModel by viewModel<PostListViewModel>()
     private var errorSnackbar: Snackbar? = null
 
     override fun onCreate(savedInstanceState: Bundle?){
@@ -23,7 +22,6 @@ class PostListActivity: AppCompatActivity() {
         binding = DataBindingUtil.setContentView(this, R.layout.activity_post_list)
         binding.postList.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
 
-        viewModel = ViewModelProviders.of(this, ViewModelFactory(this)).get(PostListViewModel::class.java)
         viewModel.errorMessage.observe(this, Observer {
             errorMessage -> if(errorMessage != null) showError(errorMessage) else hideError()
         })

app/src/main/kotlin/net/gahfy/mvvmposts/ui/post/PostListViewModel.kt

@@ -11,11 +11,8 @@ import net.gahfy.mvvmposts.base.BaseViewModel
 import net.gahfy.mvvmposts.model.Post
 import net.gahfy.mvvmposts.model.PostDao
 import net.gahfy.mvvmposts.network.PostApi
-import javax.inject.Inject
 
-class PostListViewModel(private val postDao: PostDao):BaseViewModel(){
-    @Inject
-    lateinit var postApi: PostApi
+class PostListViewModel(private val postDao: PostDao, private val postApi: PostApi):BaseViewModel(){
     val postListAdapter: PostListAdapter = PostListAdapter()
 
     val loadingVisibility: MutableLiveData<Int> = MutableLiveData()

app/src/main/kotlin/net/gahfy/mvvmposts/utils/Modules.kt

@@ -0,0 +1,31 @@
+package net.gahfy.mvvmposts.utils
+
+import android.arch.persistence.room.Room
+import android.content.Context
+import io.reactivex.schedulers.Schedulers
+import net.gahfy.mvvmposts.model.database.AppDatabase
+import net.gahfy.mvvmposts.network.PostApi
+import net.gahfy.mvvmposts.ui.post.PostListViewModel
+import org.koin.android.architecture.ext.viewModel
+import org.koin.dsl.module.Module
+import retrofit2.Retrofit
+import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
+import retrofit2.converter.moshi.MoshiConverterFactory
+
+fun postsModule(applicationContext: Context): Module = org.koin.dsl.module.applicationContext {
+    viewModel { PostListViewModel(get("dao"), get("network")) }
+    bean("dao") {
+        Room.databaseBuilder(applicationContext, AppDatabase::class.java, "posts").build().postDao()
+    }
+    bean("network") {
+        (get("retrofit") as Retrofit).create(PostApi::class.java) as PostApi
+    }
+    bean("retrofit") {
+        Retrofit.Builder()
+                .baseUrl(BASE_URL)
+                .addConverterFactory(MoshiConverterFactory.create())
+                .addCallAdapterFactory(RxJava2CallAdapterFactory.createWithScheduler(Schedulers.io()))
+                .build()
+    }
+
+}

build.gradle

@@ -5,9 +5,9 @@ buildscript {
     ext.kotlin_version = '1.2.30'
     ext.lifecycle_version = '1.1.1'
     ext.retrofit_version = '2.4.0'
-    ext.dagger2_version = '2.16'
     ext.android_support_version = '28.0.0-alpha3'
     ext.room_version = '1.1.1'
+    ext.koin_version = '0.9.3'
 
     repositories {
         google()