Use dependency injection for most singletons

music/src/main/java/de/mm20/launcher2/music/Module.kt

@@ -0,0 +1,10 @@
+package de.mm20.launcher2.music
+
+import org.koin.android.ext.koin.androidContext
+import org.koin.androidx.viewmodel.dsl.viewModel
+import org.koin.dsl.module
+
+val musicModule = module {
+    single { MusicRepository(androidContext()) }
+    viewModel { MusicViewModel(get()) }
+}

music/src/main/java/de/mm20/launcher2/music/MusicRepository.kt

@@ -24,7 +24,7 @@ import kotlinx.coroutines.*
 import java.io.File
 import java.util.concurrent.Executors
 
-class MusicRepository private constructor(val context: Context) {
+class MusicRepository(val context: Context) {
 
     private val scope = CoroutineScope(Job() + Dispatchers.Main)
 
@@ -245,12 +245,6 @@ class MusicRepository private constructor(val context: Context) {
     }
 
     companion object {
-        private lateinit var instance: MusicRepository
-
-        fun getInstance(context: Context): MusicRepository {
-            if (!::instance.isInitialized) instance = MusicRepository(context.applicationContext)
-            return instance
-        }
 
         private const val PREFS = "music"
         private const val PREFS_KEY_TITLE = "title"

music/src/main/java/de/mm20/launcher2/music/MusicViewModel.kt

@@ -1,16 +1,14 @@
 package de.mm20.launcher2.music
 
-import android.app.Application
 import android.app.PendingIntent
 import android.content.Context
 import android.graphics.Bitmap
-import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
 
-class MusicViewModel(app: Application) : AndroidViewModel(app) {
-
-    val musicRepository = MusicRepository.getInstance(app)
+class MusicViewModel(
+    val musicRepository: MusicRepository
+) : ViewModel() {
 
     val title: LiveData<String?> = musicRepository.title
     val artist: LiveData<String?> = musicRepository.artist