Use kotlinx-coroutines-guava in session demo app

I originally tried switching to `Futures.addCallback` (as a follow-up
to Issue: androidx/media#890), but it seemed like a good chance to go further into
Kotlin-ification.

Before this change, if the connection to the session failed, the app
would hang at the 'waiting' screen with nothing logged (and the music
keeps playing). This behaviour is maintained with the `try/catch` around
the `.await()` call (with additional logging). Without this, the failed
connection causes the `PlayerActivity` to crash and the music in the
background stops. The `try/catch` is used to flag to developers who
might be using this app as an example that connecting to the session
may fail, and they may want to handle that.

This change also switches `this.controller` to be `lateinit` instead of
nullable.

Issue: androidx/media#890
PiperOrigin-RevId: 638948568

constants.gradle

@@ -29,6 +29,7 @@ project.ext {
     // Use the same Guava version as the Android repo:
     // https://cs.android.com/android/platform/superproject/main/+/main:external/guava/METADATA
     guavaVersion = '33.0.0-android'
+    kotlinxCoroutinesVersion = '1.8.1'
     leakCanaryVersion = '2.10'
     mockitoVersion = '3.12.4'
     robolectricVersion = '4.11'
@@ -46,6 +47,7 @@ project.ext {
     // Updating this to 1.9.0+ will import Kotlin stdlib [internal ref: b/277891049].
     androidxCoreVersion = '1.8.0'
     androidxExifInterfaceVersion = '1.3.6'
+    androidxLifecycleVersion = '2.6.0'
     androidxMediaVersion = '1.7.0'
     androidxMultidexVersion = '2.0.1'
     androidxRecyclerViewVersion = '1.3.0'

demos/session/build.gradle

@@ -62,9 +62,12 @@ dependencies {
     // For detecting and debugging leaks only. LeakCanary is not needed for demo app to work.
     debugImplementation 'com.squareup.leakcanary:leakcanary-android:' + leakCanaryVersion
     implementation 'androidx.core:core-ktx:' + androidxCoreVersion
+    implementation 'androidx.lifecycle:lifecycle-common:' + androidxLifecycleVersion
+    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:' + androidxLifecycleVersion
     implementation 'androidx.appcompat:appcompat:' + androidxAppCompatVersion
     implementation 'androidx.multidex:multidex:' + androidxMultidexVersion
     implementation 'com.google.android.material:material:' + androidxMaterialVersion
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-guava:' + kotlinxCoroutinesVersion
     implementation project(modulePrefix + 'lib-ui')
     implementation project(modulePrefix + 'lib-session')
     implementation project(modulePrefix + 'demo-session-service')

demos/session/src/main/java/androidx/media3/demo/session/PlayerActivity.kt

@@ -18,6 +18,7 @@ package androidx.media3.demo.session
 import android.content.ComponentName
 import android.content.Context
 import android.os.Bundle
+import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -28,6 +29,9 @@ import android.widget.TextView
 import androidx.annotation.OptIn
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.ContextCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.media3.common.C.TRACK_TYPE_TEXT
 import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
@@ -40,13 +44,15 @@ import androidx.media3.session.MediaController
 import androidx.media3.session.SessionToken
 import androidx.media3.ui.PlayerView
 import com.google.common.util.concurrent.ListenableFuture
-import com.google.common.util.concurrent.MoreExecutors
+import kotlinx.coroutines.awaitCancellation
+import kotlinx.coroutines.guava.await
+import kotlinx.coroutines.launch
+
+private const val TAG = "PlayerActivity"
 
 class PlayerActivity : AppCompatActivity() {
   private lateinit var controllerFuture: ListenableFuture<MediaController>
-  private val controller: MediaController?
-    get() =
-      if (controllerFuture.isDone && !controllerFuture.isCancelled) controllerFuture.get() else null
+  private lateinit var controller: MediaController
 
   private lateinit var playerView: PlayerView
   private lateinit var mediaItemListView: ListView
@@ -57,6 +63,18 @@ class PlayerActivity : AppCompatActivity() {
   @OptIn(UnstableApi::class) // PlayerView.hideController
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
+    lifecycleScope.launch {
+      lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
+        try {
+          initializeController()
+          awaitCancellation()
+        } finally {
+          playerView.player = null
+          releaseController()
+        }
+      }
+    }
+
     setContentView(R.layout.activity_player)
     playerView = findViewById(R.id.player_view)
 
@@ -65,7 +83,6 @@ class PlayerActivity : AppCompatActivity() {
     mediaItemListView.adapter = mediaItemListAdapter
     mediaItemListView.setOnItemClickListener { _, _, position, _ ->
       run {
-        val controller = this.controller ?: return@run
         if (controller.currentMediaItemIndex == position) {
           controller.playWhenReady = !controller.playWhenReady
           if (controller.playWhenReady) {
@@ -79,18 +96,7 @@ class PlayerActivity : AppCompatActivity() {
     }
   }
 
-  override fun onStart() {
-    super.onStart()
-    initializeController()
-  }
-
-  override fun onStop() {
-    super.onStop()
-    playerView.player = null
-    releaseController()
-  }
-
-  private fun initializeController() {
+  private suspend fun initializeController() {
     controllerFuture =
       MediaController.Builder(
           this,
@@ -98,7 +104,7 @@ class PlayerActivity : AppCompatActivity() {
         )
         .buildAsync()
     updateMediaMetadataUI()
-    controllerFuture.addListener({ setController() }, MoreExecutors.directExecutor())
+    setController()
   }
 
   private fun releaseController() {
@@ -106,9 +112,13 @@ class PlayerActivity : AppCompatActivity() {
   }
 
   @OptIn(UnstableApi::class) // PlayerView.setShowSubtitleButton
-  private fun setController() {
-    val controller = this.controller ?: return
-
+  private suspend fun setController() {
+    try {
+      controller = controllerFuture.await()
+    } catch (t: Throwable) {
+      Log.w(TAG, "Failed to connect to MediaController", t)
+      return
+    }
     playerView.player = controller
 
     updateCurrentPlaylistUI()
@@ -137,8 +147,7 @@ class PlayerActivity : AppCompatActivity() {
   }
 
   private fun updateMediaMetadataUI() {
-    val controller = this.controller
-    if (controller == null || controller.mediaItemCount == 0) {
+    if (!::controller.isInitialized || controller.mediaItemCount == 0) {
       findViewById<TextView>(R.id.media_title).text = getString(R.string.waiting_for_metadata)
       findViewById<TextView>(R.id.media_artist).text = ""
       return
@@ -152,7 +161,9 @@ class PlayerActivity : AppCompatActivity() {
   }
 
   private fun updateCurrentPlaylistUI() {
-    val controller = this.controller ?: return
+    if (!::controller.isInitialized) {
+      return
+    }
     mediaItemList.clear()
     for (i in 0 until controller.mediaItemCount) {
       mediaItemList.add(controller.getMediaItemAt(i))
@@ -173,7 +184,7 @@ class PlayerActivity : AppCompatActivity() {
       returnConvertView.findViewById<TextView>(R.id.media_item).text = mediaItem.mediaMetadata.title
 
       val deleteButton = returnConvertView.findViewById<Button>(R.id.delete_button)
-      if (position == controller?.currentMediaItemIndex) {
+      if (::controller.isInitialized && position == controller.currentMediaItemIndex) {
         // Styles for the current media item list item.
         returnConvertView.setBackgroundColor(
           ContextCompat.getColor(context, R.color.playlist_item_background)
@@ -192,7 +203,6 @@ class PlayerActivity : AppCompatActivity() {
           .setTextColor(ContextCompat.getColor(context, R.color.white))
         deleteButton.visibility = View.VISIBLE
         deleteButton.setOnClickListener {
-          val controller = this@PlayerActivity.controller ?: return@setOnClickListener
           controller.removeMediaItem(position)
           updateCurrentPlaylistUI()
         }