You can use the setErrorMessage() in the PlaybackStateCompat class to accomplish this. When the PlaybackStateCompat is assigned to a Media Session, its used to describe the current operational state of the player.
private void playbackStateErrorMessage(int code, String message) {
PlaybackStateCompat.Builder playbackStateBuilder = new PlaybackStateCompat.Builder();
playbackStateBuilder.setState(PlaybackStateCompat.STATE_ERROR, -1L, 1.0F);
playbackStateBuilder.setErrorMessage(code, message);
mSession.setPlaybackState(playbackStateBuilder.build());
}
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