Some vendors' battery optimizers killed the background service quite

quickly when the app is in the background and *not* playing music. This
had the effect of breaking all player actions within the app (queue
listing, playback control, etc.).

This "starts" PlayerService every time MainActivity is resumed, which is
a noop if the service is still running, but allows retrieving app
functionality otherwise.

app/build.gradle.kts

@@ -90,8 +90,8 @@ dependencies {
   implementation(fileTree(mapOf("dir" to "libs", "include" to listOf("*.jar"))))
 
   implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.50")
-  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.2.2")
-  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.2.2")
+  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2")
+  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.2")
 
   implementation("androidx.appcompat:appcompat:1.1.0")
   implementation("androidx.core:core-ktx:1.2.0-beta01")

app/src/main/java/com/github/apognu/otter/Otter.kt

@@ -17,7 +17,7 @@ class Otter : Application() {
     fun get(): Otter = instance
   }
 
-  var eventBus: BroadcastChannel<Event> = BroadcastChannel(10)
+  val eventBus: BroadcastChannel<Event> = BroadcastChannel(10)
   val commandBus: Channel<Command> = Channel(10)
   val requestBus: BroadcastChannel<Request> = BroadcastChannel(10)
   val progressBus: BroadcastChannel<Triple<Int, Int, Int>> = ConflatedBroadcastChannel()

app/src/main/java/com/github/apognu/otter/activities/MainActivity.kt

@@ -59,8 +59,6 @@ class MainActivity : AppCompatActivity() {
       .replace(R.id.container, BrowseFragment())
       .commit()
 
-    startService(Intent(this, PlayerService::class.java))
-
     watchEventBus()
 
     CommandBus.send(Command.RefreshService)
@@ -69,6 +67,8 @@ class MainActivity : AppCompatActivity() {
   override fun onResume() {
     super.onResume()
 
+    startService(Intent(this, PlayerService::class.java))
+
     now_playing_toggle.setOnClickListener {
       CommandBus.send(Command.ToggleState)
     }