Sonos have updated their Android app adding streaming from the local library. With the updated app you can send music from local Android library to a Sonos system without having to have the content on a central PC. It’s a smart move by Sonos to enable content stored on portable devices to be played on the Sonos system, less and less people have PCs with music libraries on them. You can also stream podcasts from an Android device to a Sonos system.
You can get the updated app from the Google Play Store.