The Sonos app is a remote control that connects to the Sonos system that is playing music on the speakers. Both Google (Android) and Apple (iOS) have chosen to not allow remote playing systems the ability to access data stored on their devices. The Android decision is more recent, you can see more here. I’d recommend, if your Sonos speakers support it, using Bluetooth. However, there are many other options in that thread. 

And frankly, no, I don’t consider it ‘fraud’ by any stretch of the imagination. Especially if you’ve read both Sonos’ marketing materials, and the TOS when you start using their software. 

That’s not how it works. Sonos has openen up it’s systems to any music service. It is up to the music service if and how they implement Sonos. Some have a direct link, like Spotify Connect, others can be added via the Sonos app. Others do nit have any possibilities with Sonos.

I do not agree to this argument. Saying “sonos allows other music services to integrate” still means that other services need to develop some integration instead of simply being able of using other any services  as possible with other, less expensive systems

Thank your  answer (although I strongly disagree with your second comment).

If I understand the thread correctly it is about the particular problem playing media stored on a device. My question is rather about a general solution sending any audio output produced by any Android App towards the Sonons system. Is there any?

And: Does the limitation discussed here also exists on Apple devices or does AirDrop allow the audio output of any App to Sonos?

For Apple devices, you could use airplay.  I think the corresponding feature for android you’re looking for is chromecast, which Sonos does not support.

The Sonos system existed before there were even smartphones, and thus it’s designed to not really rely on smart phones.  The speaker itself is really the player, and does not need audio sent to it from a phone.  While originally you could only play from an aux input or your local library of tracks, because there was no streaming services, it’s since adapted so that you can enter your streaming service credentials in the Sonos app.  The speaker itself will stream the audio, you don’t need your phone to play the music at all.

There are two reasons why it’s up to the streaming service to build the integration to Sonos, rather than Sonos integrating to each service.  One is that this allows the service to better control how the service is presented to their customer.  Two, their are limited resources on the speakers, and they cannot build 100 different interfaces.

Some streaming apps having casting abilities to Sonos, so that you can use the service app rather than Sonos app.  But it would obviously up to the service to support this.

As far as a general way of playing anything on your phone to Sonos, several devices support bluetooth, as already suggested.  If you don’t want to use the Sonos app, don’t want to use bluetooth, and want to use apps that don’t have casting abilities, and are using an android device, that Sonos doesn’t have a solution for you.  You would need to find something with chromecast support. 

Personally I’ve never had an issue with the lack of chromecast.  I have used chromecast once or twice to cast youtube on to my TV, but then Sonos plays whats on the TV so I’m not missing anything.