play a downloaded mp3 in xamarin forms - audio

Question

I am able to play a file "test.mp3" added as a resource into the "Resources\Sounds\" folder of my pcl project by calling
AudioManager.Audio.Manager.PlaySound("test.mp3");
Now I am trying to play an audio file that I have downloaded from my webapi service. I am using the RestSharp library to download the file and the PCLStorage library to store the file:
try
{
var fileId = new Guid("test2");
IFolder rootFolder = FileSystem.Current.LocalStorage;
IFolder resources = await rootFolder.CreateFolderAsync("Resources", CreationCollisionOption.OpenIfExists);
IFolder soundsFolder = await rootFolder.CreateFolderAsync("Sounds", CreationCollisionOption.OpenIfExists);
IFile myFile = await soundsFolder.CreateFileAsync($"{fileId}.mp3", CreationCollisionOption.ReplaceExisting);
using (var stream = await myFile.OpenAsync(fileAccess: FileAccess.ReadAndWrite))
{
var request = new RestRequest($"{fileId}");
var client = new RestClient();
client.BaseUrl = new System.Uri("http://10.0.2.2/MyApp.WebApi/api/");
var bytes = client.DownloadData(request);
foreach (var myByte in bytes)
{
stream.WriteByte(myByte);
}
}
}
catch (Exception e)
{
}
I also tried saving the file to the root dir but this also doesn't work.
The file seems to download just fine as far as I can tell (no errors). But I have yet to find a way to verify this by locating the file on the android emulator. I guess I first need to install the play store somehow and then download ES File explorer to see the file structure on the android emulator.
The problem is that when I try to play the soundfile in the same way I did with the embedded resource it won't work.
AudioManager.Audio.Manager.PlaySound("test2.mp3");
I guess this is because of the magic that happens during compile time to migrate the embedded resources to "somewhere" on the android emulator.
My main problem is that I do not understand what path to use to
write the file (tried resources/sounds and root)
read the file (tried
resources/sounds and root)
in order to be able to play the file

Answer 1

It turns out the AudioManager library assumes sounds are always Assets.
In it's NewSound method in the android code it tries to build an AssetFileDescriptor by using the following line:
Forms.Context.Assets.OpenFd(filePath);
I guess this method wants a filepath relative to the assets folder (for compiled resources) and throws a FileNotFoundException otherwise. This exception, however thrown, did not reach my catch statement in my pcl code. (it looks like it get's swallowed somewhere in the android -> pcl layer??)
Now I am using the SoundPool.LoadAsync with a filepath rather than a AssetFileDescriptor and this fixes my problem.
Yay!