Use ViewmodelScope instead of creating coroutine scope

Author: SudKul

app/build.gradle

@@ -29,7 +29,7 @@ android {
         targetSdkVersion 30
         versionCode 1
         versionName "1.0"
-        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        multiDexEnabled true
         vectorDrawables.useSupportLibrary = true
     }
     buildTypes {
@@ -79,6 +79,7 @@ dependencies {
 
     // ViewModel and LiveData (arch components)
     implementation "androidx.lifecycle:lifecycle-extensions:$version_lifecycle_extensions"
+    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
 
     // Logging
     implementation "com.jakewharton.timber:timber:$version_timber"
@@ -90,6 +91,9 @@ dependencies {
     implementation "androidx.room:room-runtime:$version_room"
     kapt "androidx.room:room-compiler:$version_room"
 
+    // Kotlin Extensions and Coroutines support for Room
+    implementation "androidx.room:room-ktx:$room_version"
+
     // WorkManager
     implementation "android.arch.work:work-runtime-ktx:$version_work"
 }

app/src/main/java/com/example/android/devbyteviewer/viewmodels/DevByteViewModel.kt

@@ -21,6 +21,7 @@ import android.app.Application
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
 import com.example.android.devbyteviewer.database.getDatabase
 import com.example.android.devbyteviewer.repository.VideosRepository
 import kotlinx.coroutines.CoroutineScope
@@ -41,19 +42,12 @@ import kotlinx.coroutines.launch
 class DevByteViewModel(application: Application) : AndroidViewModel(application) {
 
     /**
-     * This is the job for all coroutines started by this ViewModel.
      *
-     * Cancelling this job will cancel all coroutines started by this ViewModel.
      */
-    private val viewModelJob = SupervisorJob()
 
     /**
-     * This is the main scope for all coroutines launched by MainViewModel.
      *
-     * Since we pass viewModelJob, you can cancel all coroutines launched by uiScope by calling
-     * viewModelJob.cancel()
      */
-    private val viewModelScope = CoroutineScope(viewModelJob + Dispatchers.Main)
 
     private val database = getDatabase(application)
     private val videosRepository = VideosRepository(database)
@@ -70,12 +64,7 @@ class DevByteViewModel(application: Application) : AndroidViewModel(application)
     val playlist = videosRepository.videos
 
     /**
-     * Cancel all coroutines when the ViewModel is cleared
      */
-    override fun onCleared() {
-        super.onCleared()
-        viewModelJob.cancel()
-    }
 
     /**
      * Factory for constructing DevByteViewModel with parameter

build.gradle

@@ -27,6 +27,7 @@ buildscript {
         version_gradle = '4.0.1'
         version_kotlin = "1.3.72"
         version_lifecycle_extensions = "2.2.0"
+        lifecycle_version = "2.2.0"
         version_room = "2.2.5"
         version_appcompat = "1.2.0"
         version_fragment = "1.0.0"