AudioService.addToQueue generates exception: "This session doesn't support queue management operations".

[BeMacized]

Hello!

While experimenting with this plugin, I ran into the issue that whenever I call AudioService.addQueueItem, the following exception is thrown:

E/MethodChannel#ryanheise.com/audioService(11872): Failed to handle method call
E/MethodChannel#ryanheise.com/audioService(11872): java.lang.UnsupportedOperationException: This session doesn't support queue management operations
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.support.v4.media.session.MediaControllerCompat$MediaControllerImplApi21.addQueueItem(MediaControllerCompat.java:1988)
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.support.v4.media.session.MediaControllerCompat.addQueueItem(MediaControllerCompat.java:316)
E/MethodChannel#ryanheise.com/audioService(11872): 	at com.ryanheise.audioservice.AudioServicePlugin$ClientHandler.onMethodCall(AudioServicePlugin.java:316)
E/MethodChannel#ryanheise.com/audioService(11872): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:200)
E/MethodChannel#ryanheise.com/audioService(11872): 	at io.flutter.view.FlutterNativeView.handlePlatformMessage(FlutterNativeView.java:163)
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.os.MessageQueue.next(MessageQueue.java:326)
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.os.Looper.loop(Looper.java:160)
E/MethodChannel#ryanheise.com/audioService(11872): 	at android.app.ActivityThread.main(ActivityThread.java:6863)
E/MethodChannel#ryanheise.com/audioService(11872): 	at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#ryanheise.com/audioService(11872): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
E/MethodChannel#ryanheise.com/audioService(11872): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

This error was produced with the following code, based off the example in this repo:
https://gist.github.com/BeMacized/5ccc11f43c4b18bd1e40a1e539082721

Any idea what might cause this?

[ryanheise]

I've just published release 0.0.9 which should now support queue/playlist management. Just an important point about the way it works, this will only be enabled if you implement one or more of the queue callbacks passed into AudioServiceBackground.run. In your case, you would want to implement onAddToQueue. In here, you should then call setQueue to actually update the queue.

[BeMacized]

Thank you very much for the help!

I have tried the new update, and I could sort of get it to work. However, I am running into trouble when I try to queue items immediately after starting the audio service. Currently, awaiting AudioService.start, does not wait for the background task to start (and therefore queue management to be enabled).

Therefore, the following snippet still throws the same exception as before:

MediaItem mediaItem = MediaItem(
    id: 'audio_1', album: 'Sample Album', title: 'Sample Title');

await AudioService.start(
    backgroundTask: backgroundTask,
    resumeOnClick: true,
    notificationChannelName: 'Audio Service Demo',
    notificationColor: 0xFF2196f3,
    androidNotificationIcon: 'mipmap/ic_launcher',
);

// Uncomment delay to "fix".
// await Future.delayed(Duration(seconds: 5));

await AudioService.addQueueItem(mediaItem);

However, when uncommenting the delay line, as a crude way of waiting for the background task to start, everything works as it should.

Is there maybe some way to await the background task being started?

[ryanheise]

I like that idea. I've implemented and committed it if you want to try it out. I haven't published a new release to the package server since I notice a pull request which I want to get to first.

[ryanheise]

This fix and your pull request are now included in release 0.0.10.

[BeMacized]

Seems to work fine, thank you!