How do I 'cast' music to my Sonos devices from an Android phone?

I don’t think Android (Google) provides a similar casting system to Sonos devices. You’d need to place your music on a PC or NAS, or even (I’ve heard) iBroadcast. 

Hmm, thanks for the reply Bruce - but I’m not really talking about a local music library. When using my iPhone, I could be streaming music from Apple Music and then simply press the “Airplay” button and select a different speaker, switching it from the iPhone to the Sonos speaker.

Now that you mention it, I do have a local music library set up and shared to all my devices using Jellyfin… but again, Sonos doesn’t recognise that either. With my iPhone I could play music from my Jellyfin server using an app like Ampfin and then just “send” it to the Sonos using Airplay.

But now I’m on Android, I can’t do any of that. I feel like this is a restriction of the Sonos speaker more than the Android phone, maybe? If the speaker supported Chromecast, would this work? Does the Sonos support Chromecast?

Sorry, I’m not familiar with ‘Jellyfin’. Is that a hardware device, or software? Where is the library itself stored, locally?

Sonos, being a Linux based OS, connects its speakers via SMB to the location of the stored music. If it is cloud based, to my knowledge, they can’t connect, as there is no SMB method for connection.

It doesn’t connect through the app itself, which uses the OS that it is running on for connections, and not the speaker’s OS. One of the easy reasons to see it’s a remote control, and not an actual ‘player’ itself. 

My suspicion is, given Google’s failed attempt to steal some of the copyrighted efforts by Sonos, there’s some ill will there, and they’ve never added the ability to cast from the Android system. Sonos doesn’t have much control over that, unfortunately, they’ve already written that system for Apple to use, Google just needs to include it on for Android. And Sonos customers, like you, end up paying the price. IMHO. I don’t work for either company, much less at a level to really know. 

Griping at Sonos might make you feel better. You’re not the first to do so, either, it’s been going on for years. But ultimately, it is Google who needs to allow Sonos to finalize any implementation, and change the Android codebase to recognize Sonos as a viable target. I’m pretty certain Sonos, along with thousands, or even millions of customers, would be delighted.