Minor session demo app improvements

Basically this change removes a bug that makes video playback stuck when
a video is playing and the user taps the UMO notification to get to
the player activity.

- Use `launchMode="singleTop"` for `PlayerActivity`
- Change session activity to a back stacked activity on service `onDestroy`.

Using a back stacked activity `onDestroy()` will be useful once this demo
app implements playback resumption.

The rest of the changes are aesthetic:

- clean up and optimize screen space usage in UI of `PlayerActivity`
- changed some colors, paddings and spacings
- adds a default artwork for the `PlayerView`

PiperOrigin-RevId: 534152052

demos/session/src/main/AndroidManifest.xml

@@ -40,7 +40,9 @@
 
     <activity
         android:name=".PlayerActivity"
-        android:exported="true"/>
+        android:exported="true"
+        android:launchMode="singleTop"
+        android:theme="@style/Theme.AppCompat.NoActionBar"/>
 
     <activity
         android:name=".PlayableFolderActivity"

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

@@ -17,7 +17,6 @@ package androidx.media3.demo.session
 
 import android.content.ComponentName
 import android.content.Context
-import android.content.Intent
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.MenuItem
@@ -70,9 +69,9 @@ class MainActivity : AppCompatActivity() {
 
     findViewById<ExtendedFloatingActionButton>(R.id.open_player_floating_button)
       .setOnClickListener {
-        // display the playing media items
+        // Start the session activity that shows the playback activity. The System UI uses the same
-        val intent = Intent(this, PlayerActivity::class.java)
+        // intent in the same way to start the activity from the notification.
-        startActivity(intent)
+        browser?.sessionActivity?.send()
       }
 
     onBackPressedDispatcher.addCallback(

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

@@ -51,6 +51,7 @@ class PlayableFolderActivity : AppCompatActivity() {
 
   companion object {
     private const val MEDIA_ITEM_ID_KEY = "MEDIA_ITEM_ID_KEY"
+
     fun createIntent(context: Context, mediaItemID: String): Intent {
       val intent = Intent(context, PlayableFolderActivity::class.java)
       intent.putExtra(MEDIA_ITEM_ID_KEY, mediaItemID)
@@ -77,8 +78,7 @@ class PlayableFolderActivity : AppCompatActivity() {
         browser.shuffleModeEnabled = false
         browser.prepare()
         browser.play()
-        val intent = Intent(this, PlayerActivity::class.java)
+        browser.sessionActivity?.send()
-        startActivity(intent)
       }
     }
 
@@ -104,9 +104,9 @@ class PlayableFolderActivity : AppCompatActivity() {
 
     findViewById<ExtendedFloatingActionButton>(R.id.open_player_floating_button)
       .setOnClickListener {
-        // display the playing media items
+        // Start the session activity that shows the playback activity. The System UI uses the same
-        val intent = Intent(this, PlayerActivity::class.java)
+        // intent in the same way to start the activity from the notification.
-        startActivity(intent)
+        browser?.sessionActivity?.send()
       }
   }
 

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

@@ -18,6 +18,7 @@ package androidx.media3.demo.session
 import android.annotation.SuppressLint
 import android.app.NotificationChannel
 import android.app.NotificationManager
+import android.app.PendingIntent
 import android.app.PendingIntent.*
 import android.app.TaskStackBuilder
 import android.content.Intent
@@ -55,6 +56,7 @@ class PlaybackService : MediaLibraryService() {
       "android.media3.session.demo.SHUFFLE_OFF"
     private const val NOTIFICATION_ID = 123
     private const val CHANNEL_ID = "demo_session_notification_channel_id"
+    private val immutableFlag = if (Build.VERSION.SDK_INT >= 23) FLAG_IMMUTABLE else 0
   }
 
   override fun onCreate() {
@@ -78,14 +80,15 @@ class PlaybackService : MediaLibraryService() {
   }
 
   override fun onTaskRemoved(rootIntent: Intent?) {
-    if (!player.playWhenReady) {
+    if (!player.playWhenReady || player.mediaItemCount == 0) {
       stopSelf()
     }
   }
 
   override fun onDestroy() {
-    player.release()
+    mediaLibrarySession.setSessionActivity(getBackStackedActivity())
     mediaLibrarySession.release()
+    player.release()
     clearListener()
     super.onDestroy()
   }
@@ -235,18 +238,9 @@ class PlaybackService : MediaLibraryService() {
         .build()
     MediaItemTree.initialize(assets)
 
-    val sessionActivityPendingIntent =
-      TaskStackBuilder.create(this).run {
-        addNextIntent(Intent(this@PlaybackService, MainActivity::class.java))
-        addNextIntent(Intent(this@PlaybackService, PlayerActivity::class.java))
-
-        val immutableFlag = if (Build.VERSION.SDK_INT >= 23) FLAG_IMMUTABLE else 0
-        getPendingIntent(0, immutableFlag or FLAG_UPDATE_CURRENT)
-      }
-
     mediaLibrarySession =
       MediaLibrarySession.Builder(this, player, librarySessionCallback)
-        .setSessionActivity(sessionActivityPendingIntent)
+        .setSessionActivity(getSingleTopActivity())
         .setBitmapLoader(CacheBitmapLoader(DataSourceBitmapLoader(/* context= */ this)))
         .build()
     if (!customLayout.isEmpty()) {
@@ -255,6 +249,23 @@ class PlaybackService : MediaLibraryService() {
     }
   }
 
+  private fun getSingleTopActivity(): PendingIntent {
+    return getActivity(
+      this,
+      0,
+      Intent(this, PlayerActivity::class.java),
+      immutableFlag or FLAG_UPDATE_CURRENT
+    )
+  }
+
+  private fun getBackStackedActivity(): PendingIntent {
+    return TaskStackBuilder.create(this).run {
+      addNextIntent(Intent(this@PlaybackService, MainActivity::class.java))
+      addNextIntent(Intent(this@PlaybackService, PlayerActivity::class.java))
+      getPendingIntent(0, immutableFlag or FLAG_UPDATE_CURRENT)
+    }
+  }
+
   private fun getShuffleCommandButton(sessionCommand: SessionCommand): CommandButton {
     val isOn = sessionCommand.customAction == CUSTOM_COMMAND_TOGGLE_SHUFFLE_MODE_ON
     return CommandButton.Builder()

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

@@ -19,7 +19,6 @@ import android.content.ComponentName
 import android.content.Context
 import android.os.Bundle
 import android.view.LayoutInflater
-import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ArrayAdapter
@@ -46,41 +45,33 @@ class PlayerActivity : AppCompatActivity() {
     get() = if (controllerFuture.isDone) controllerFuture.get() else null
 
   private lateinit var playerView: PlayerView
-  private lateinit var mediaList: ListView
+  private lateinit var mediaItemListView: ListView
-  private lateinit var mediaListAdapter: PlayingMediaItemArrayAdapter
+  private lateinit var mediaItemListAdapter: MediaItemListAdapter
-  private val subItemMediaList: MutableList<MediaItem> = mutableListOf()
+  private val mediaItemList: MutableList<MediaItem> = mutableListOf()
+  private var lastMediaItemId: String? = null
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     setContentView(R.layout.activity_player)
     playerView = findViewById(R.id.player_view)
 
-    mediaList = findViewById(R.id.current_playing_list)
+    mediaItemListView = findViewById(R.id.current_playing_list)
-    mediaListAdapter = PlayingMediaItemArrayAdapter(this, R.layout.folder_items, subItemMediaList)
+    mediaItemListAdapter = MediaItemListAdapter(this, R.layout.folder_items, mediaItemList)
-    mediaList.adapter = mediaListAdapter
+    mediaItemListView.adapter = mediaItemListAdapter
-    mediaList.setOnItemClickListener { _, _, position, _ ->
+    mediaItemListView.setOnItemClickListener { _, _, position, _ ->
       run {
         val controller = this.controller ?: return@run
-        controller.seekToDefaultPosition(/* windowIndex= */ position)
+        if (controller.currentMediaItemIndex == position) {
-        mediaListAdapter.notifyDataSetChanged()
+          controller.playWhenReady = !controller.playWhenReady
+          if (controller.playWhenReady) {
+            playerView.hideController()
+          }
+        } else {
+          controller.seekToDefaultPosition(/* mediaItemIndex= */ position)
+          mediaItemListAdapter.notifyDataSetChanged()
         }
       }
-
-    findViewById<ImageView>(R.id.shuffle_switch).setOnClickListener {
-      val controller = this.controller ?: return@setOnClickListener
-      controller.shuffleModeEnabled = !controller.shuffleModeEnabled
     }
-
-    findViewById<ImageView>(R.id.repeat_switch).setOnClickListener {
-      val controller = this.controller ?: return@setOnClickListener
-      when (controller.repeatMode) {
-        Player.REPEAT_MODE_ALL -> controller.repeatMode = Player.REPEAT_MODE_OFF
-        Player.REPEAT_MODE_OFF -> controller.repeatMode = Player.REPEAT_MODE_ONE
-        Player.REPEAT_MODE_ONE -> controller.repeatMode = Player.REPEAT_MODE_ALL
-      }
-    }
-
-    supportActionBar!!.setDisplayHomeAsUpEnabled(true)
   }
 
   override fun onStart() {
@@ -94,14 +85,6 @@ class PlayerActivity : AppCompatActivity() {
     releaseController()
   }
 
-  override fun onOptionsItemSelected(item: MenuItem): Boolean {
-    if (item.itemId == android.R.id.home) {
-      onBackPressed()
-      return true
-    }
-    return super.onOptionsItemSelected(item)
-  }
-
   private fun initializeController() {
     controllerFuture =
       MediaController.Builder(
@@ -123,8 +106,6 @@ class PlayerActivity : AppCompatActivity() {
 
     updateCurrentPlaylistUI()
     updateMediaMetadataUI(controller.mediaMetadata)
-    updateShuffleSwitchUI(controller.shuffleModeEnabled)
-    updateRepeatSwitchUI(controller.repeatMode)
     playerView.setShowSubtitleButton(controller.currentTracks.isTypeSupported(TRACK_TYPE_TEXT))
 
     controller.addListener(
@@ -133,14 +114,6 @@ class PlayerActivity : AppCompatActivity() {
           updateMediaMetadataUI(mediaItem?.mediaMetadata ?: MediaMetadata.EMPTY)
         }
 
-        override fun onShuffleModeEnabledChanged(shuffleModeEnabled: Boolean) {
-          updateShuffleSwitchUI(shuffleModeEnabled)
-        }
-
-        override fun onRepeatModeChanged(repeatMode: Int) {
-          updateRepeatSwitchUI(repeatMode)
-        }
-
         override fun onTracksChanged(tracks: Tracks) {
           playerView.setShowSubtitleButton(tracks.isTypeSupported(TRACK_TYPE_TEXT))
         }
@@ -148,48 +121,26 @@ class PlayerActivity : AppCompatActivity() {
     )
   }
 
-  private fun updateShuffleSwitchUI(shuffleModeEnabled: Boolean) {
-    val resId =
-      if (shuffleModeEnabled) R.drawable.exo_styled_controls_shuffle_on
-      else R.drawable.exo_styled_controls_shuffle_off
-    findViewById<ImageView>(R.id.shuffle_switch)
-      .setImageDrawable(ContextCompat.getDrawable(this, resId))
-  }
-
-  private fun updateRepeatSwitchUI(repeatMode: Int) {
-    val resId: Int =
-      when (repeatMode) {
-        Player.REPEAT_MODE_OFF -> R.drawable.exo_styled_controls_repeat_off
-        Player.REPEAT_MODE_ONE -> R.drawable.exo_styled_controls_repeat_one
-        Player.REPEAT_MODE_ALL -> R.drawable.exo_styled_controls_repeat_all
-        else -> R.drawable.exo_styled_controls_repeat_off
-      }
-    findViewById<ImageView>(R.id.repeat_switch)
-      .setImageDrawable(ContextCompat.getDrawable(this, resId))
-  }
-
   private fun updateMediaMetadataUI(mediaMetadata: MediaMetadata) {
-    val title: CharSequence = mediaMetadata.title ?: getString(R.string.no_item_prompt)
+    val title: CharSequence = mediaMetadata.title ?: "getString(R.string.no_item_prompt)"
 
-    findViewById<TextView>(R.id.video_title).text = title
+    findViewById<TextView>(R.id.media_title).text = title
-    findViewById<TextView>(R.id.video_album).text = mediaMetadata.albumTitle
+    findViewById<TextView>(R.id.media_artist).text = mediaMetadata.artist
-    findViewById<TextView>(R.id.video_artist).text = mediaMetadata.artist
-    findViewById<TextView>(R.id.video_genre).text = mediaMetadata.genre
 
     // Trick to update playlist UI
-    mediaListAdapter.notifyDataSetChanged()
+    mediaItemListAdapter.notifyDataSetChanged()
   }
 
   private fun updateCurrentPlaylistUI() {
     val controller = this.controller ?: return
-    subItemMediaList.clear()
+    mediaItemList.clear()
     for (i in 0 until controller.mediaItemCount) {
-      subItemMediaList.add(controller.getMediaItemAt(i))
+      mediaItemList.add(controller.getMediaItemAt(i))
     }
-    mediaListAdapter.notifyDataSetChanged()
+    mediaItemListAdapter.notifyDataSetChanged()
   }
 
-  private inner class PlayingMediaItemArrayAdapter(
+  private inner class MediaItemListAdapter(
     context: Context,
     viewID: Int,
     mediaItemList: List<MediaItem>
@@ -201,23 +152,31 @@ 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) {
-        returnConvertView.setBackgroundColor(ContextCompat.getColor(context, R.color.white))
+        // Styles for the current media item list item.
-        returnConvertView
+        returnConvertView.setBackgroundColor(
-          .findViewById<TextView>(R.id.media_item)
+          ContextCompat.getColor(context, R.color.playlist_item_background)
-          .setTextColor(ContextCompat.getColor(context, R.color.black))
+        )
-      } else {
-        returnConvertView.setBackgroundColor(ContextCompat.getColor(context, R.color.black))
         returnConvertView
           .findViewById<TextView>(R.id.media_item)
           .setTextColor(ContextCompat.getColor(context, R.color.white))
-      }
+        deleteButton.visibility = View.GONE
-
+      } else {
-      returnConvertView.findViewById<Button>(R.id.delete_button).setOnClickListener {
+        // Styles for any other media item list item.
+        returnConvertView.setBackgroundColor(
+          ContextCompat.getColor(context, R.color.player_background)
+        )
+        returnConvertView
+          .findViewById<TextView>(R.id.media_item)
+          .setTextColor(ContextCompat.getColor(context, R.color.white))
+        deleteButton.visibility = View.VISIBLE
+        deleteButton.setOnClickListener {
           val controller = this@PlayerActivity.controller ?: return@setOnClickListener
           controller.removeMediaItem(position)
           updateCurrentPlaylistUI()
         }
+      }
 
       return returnConvertView
     }

demos/session/src/main/res/layout/activity_player.xml

@@ -19,7 +19,7 @@
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
-  android:background="@color/black"
+  android:background="@color/player_background"
   tools:context=".PlayerActivity">
 
   <androidx.media3.ui.AspectRatioFrameLayout
@@ -28,77 +28,47 @@
     >
     <androidx.media3.ui.PlayerView
       android:id="@+id/player_view"
+      android:background="@color/player_background"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
-      app:use_artwork="true" />
+      app:default_artwork="@drawable/artwork_placeholder"
+      app:repeat_toggle_modes="one|all"
+      app:show_shuffle_button="true"
+      app:shutter_background_color="@color/player_background" />
   </androidx.media3.ui.AspectRatioFrameLayout>
 
-
   <TextView
-    android:id="@+id/video_title"
+    android:id="@+id/media_artist"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:paddingLeft="10dp"
+    android:paddingStart="10dp"
+    android:paddingTop="10dp"
+    android:textColor="@color/white"
+    android:textSize="14sp"/>
+
+  <TextView
+    android:id="@+id/media_title"
+    android:ellipsize="end"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:maxLines="1"
+    android:paddingLeft="10dp"
     android:paddingBottom="10dp"
+    android:paddingStart="10dp"
     android:textColor="@color/white"
     android:textSize="20sp" />
 
-  <TextView
+  <View
-    android:id="@+id/video_album"
+    android:background="@color/divider"
-    android:layout_width="match_parent"
+    android:layout_height="1dp"
-    android:layout_height="wrap_content"
+    android:layout_width="match_parent" />
-    android:paddingLeft="10dp"
-    android:paddingBottom="10dp"
-    android:textColor="@color/white"
-    android:textSize="20sp" />
-
-  <TextView
-    android:id="@+id/video_artist"
-    android:layout_width="match_parent"
-    android:layout_height="wrap_content"
-    android:textColor="@color/white"
-    android:paddingLeft="10dp"
-    android:paddingBottom="10dp"/>
-
-  <TextView
-    android:id="@+id/video_genre"
-    android:layout_width="match_parent"
-    android:layout_height="wrap_content"
-    android:textColor="@color/white"
-    android:paddingLeft="10dp"
-    android:paddingBottom="10dp"
-    android:textSize="12sp" />
-
-  <LinearLayout
-    android:gravity="center_vertical"
-    android:layout_width="match_parent"
-    android:layout_height="wrap_content">
-
-    <ImageView
-      android:id="@+id/shuffle_switch"
-      android:layout_width="wrap_content"
-      android:layout_height="wrap_content"
-      android:contentDescription="@string/shuffle"
-      android:src="@drawable/exo_styled_controls_shuffle_off"
-      android:textColor="@color/white" />
-
-
-    <ImageView
-      android:layout_margin="@dimen/exo_icon_horizontal_margin"
-      android:id="@+id/repeat_switch"
-      android:layout_width="wrap_content"
-      android:layout_height="wrap_content"
-      android:src="@drawable/exo_styled_controls_repeat_off"
-      android:textColor="@color/white"
-      android:contentDescription="@string/repeat"
-      />
-  </LinearLayout>
 
   <ListView
     android:id="@+id/current_playing_list"
-    android:layout_width="match_parent"
     android:divider="@drawable/divider"
     android:dividerHeight="1px"
+    android:layout_width="match_parent"
     android:layout_height="wrap_content" />
 
 </LinearLayout>

demos/session/src/main/res/layout/playlist_items.xml

@@ -25,6 +25,8 @@
     android:layout_height="wrap_content"
     android:gravity="center_vertical"
     android:paddingStart="10dp"
+    android:maxLines="1"
+    android:ellipsize="end"
     android:textColor="@color/white"
     android:paddingEnd="10dp"
     android:minHeight="50dp" />
@@ -35,6 +37,7 @@
     android:layout_width="50dp"
     android:layout_height="match_parent"
     android:id="@+id/delete_button"
+    android:backgroundTint="@color/playlist_item_foreground"
     android:background="@drawable/baseline_playlist_remove_white_48"
     />
 

demos/session/src/main/res/values/colors.xml

@@ -22,4 +22,9 @@
   <color name="black">#FF000000</color>
   <color name="white">#FFFFFFFF</color>
   <color name="grey">#FF999999</color>
+  <color name="background">#292929</color>
+  <color name="player_background">#1c1c1c</color>
+  <color name="playlist_item_background">#363434</color>
+  <color name="playlist_item_foreground">#635E5E</color>
+  <color name="divider">#646464</color>
 </resources>