mediabrowser | Laravel packages that provide a basic user interface | File Utils library

Finally found the source of the problem. I was overriding onBind and returning null.

Your media service extends MediaBrowserServiceCompat. At first, this looks like an issue with MediaBrowserServiceCompat. androidx.media:media:1.1.0 is the latest release, and the latest sources for MediaBrowserServiceCompat are currently here.

MediaBrowserServiceCompat is a base service class that delegates to a subclass of the AOSP MediaBrowserService class (sources). One tricky bit here is that while MediaBrowserService is a service, when used by MediaBrowserServiceCompat it's not actually created as a real Android service but instead created as a mere delegate that MediaBrowserServiceCompat passes callbacks to. That in itself means it's easy to make mistakes.

The MediaBrowserService subclass holds a reference to the MediaBrowserServiceCompat instance so that t

The leak trace shows there's a native reference to MediaBrowserService$ServiceBinder. When MediaBrowserServiceCompat receives its onBind() call it returns the binder from MediaBrowserService. That binder should be held as long as MediaBrowserServiceCompat is alived, and released when it's destroyed. At this point we need a heap dump to dig further.

I downloaded the sources, built the app and deployed it on an emulator (API 29) and was able to reproduce the leak by pressing back. I noticed that the MediaSessionCompat constructor javadoc states "You must call {@link #release()} when finished with the session.". I tried calling that in onDestroy() but the leak still happens.

I'm wondering if this happens only with app compat, or also with AOSP. I ported the code back to AOSP (no compat) and the same thing is happening.

Reference: https://developer.android.com/guide/topics/media-apps/audio-app/building-a-mediabrowserservice

In order to understand this, it is important to have a clear understanding of what a MediaItem represents. In the reference the following statement is provided "Your service is responsible for associating the ID with the appropriate menu node or content item." You need to use the MediaItem class to define a hierarchy of items (PLAYABLE or BROWSEABLE). An example would be

root (Not a media item, but can be subscribed to return the highest level fo Media items) -> songs(browseable) albums (browseable) artists (browseable)

the albums MediaItem, if subscribed to, would return something like -> album1 (browseable) album2 (browseable)

and in your album1 you would have your playable MP3s e.g. -> song1.mp3 (playable) song2.mp3 (playable)

For all browseable MediaItems we can choose to "subscribe" to them to get all of the child nodes; which helps when we one to dynamically build our UI.

Relating this concept to the software architecture, you need to think about what is going to access onGetRoot and onLoadChildren. They are part of a MediaBrowserService, therefore the functions will be interacted by a MediaBrowser.

1) onGetRoot() is called to gain the authority to access the Media that the MediaBrowserService provides. It will return a "root ID" which can be subscribed to and return the MediaItems at the highest level of your hierarchy. I.e. in the above example subscribing to the root node would return Songs, Albums and Artists.

onLoadChildren() is therefore called when we choose to subscribe to MediaItems to get their children nodes.

2) This does not relate to the root directory but rather a "root ID" used to subscribe to the top (root) level of your self defined hierarchy

3) OnLoadChildren is called by the subscribe method of the MediaBrowser and will return all child MediaItems (browseable or playable).

4) OnLoadChildren can return a playlist if you wish. To do so define a mediaItem "playlist name" which can be browseable and it will return the MediaItems in that playlist.

https://stackoverflow.com/a/43676925/11485632 - this answer helped me to solve the problem. It turned out you can't even have your own Binder implemented. After removing overridden onBind(Intent intent) in Service.java callback started being invoked.

My issue was unrelated to the MediaBrowserServiceCompat class. The issue was coming about because I was calling result.detach() in order to implement some asynchronous data fetching, and the listener I was using had both the parentId and result variables from the onLoadChildren method passed in and assigned final val rather than var.

I still don't fully understand why this occurs, whether it's an underlying result of using a Player.EventListener within another asynchronous network call listener, but the solution was to create and assign a variable (and perhaps someone else can explain this phenomenon):

It turns out that the whole problem was caused by having another BroadcastReceiver handling MEDIA_BUTTON declared in my app's Manifest. By removing that receiver everything works now.

Your assumption is correct, you should not embed the wear APK inside the phone APK (this was the old way of doing it). However, you still need to publish the phone APK.

There are only 2 APKs in your screen shot. There should be 3 in total: phone APK for AW 1.x, wear APK for AW 1.x, and wear APK for AW 2.x.

Make sure that the AW 2.0 APK has the highest version code, followed by the AW 1.x watch APK, and finally the AW 1.x phone APK.

Note that that the wearAppUnbundled true flag (in your phone gradle file) is only needed if you've previously published an AW 1.x app with an embedded wear APK (but it shouldn't hurt to include it otherwise).

As you discovered, MediaBrowserServiceCompat is already a bound service - you cannot and should not override onBind().

Instead, you must connect to your MediaBrowserServiceCompat with a MediaBrowserCompat as per the documentation. Once connected, you can trigger custom methods, like doMagic by:

1. Create a MediaControllerCompat from your MediaBrowserCompat instance, following the documentation
2. Call sendCommand, passing in a command String which uniquely identifies your command (say, doMagic), any parameters you wish to pass to the method, and a ResultReceiver if you want a return value.
3. In the MediaSessionCompat.Callback registered with your MediaBrowserServiceCompat, override onCommand() and handle the command (say, by calling doMagic).

An example of this approach was offered in this blog post

It was a silly mistake. I for got to add setMediaPlaybackState(PlaybackStateCompat.STATE_PLAYING); after my mediaPlayer was prepared.