A widget for Android phones for pause/resume, stop and previous/next would be great.
I find it a bit slow to open the webapp (which sometimes even loads “from scratch”) or doesn’t load and I have to kill the process and restart…
And a question: A few days ago you guys retweeted a link to “volumio android apps” and there was one called volumio web app. I would like to know in which way is it better than going to volumio’s IP in chrome and then choose “add to desktop”?
Volumio uses MPD (Music Player Daemon) to play webradio/local files/nas and a Spotify library to manage Spotify plays.
If you don’t use Spotify, you can download any Android MPD-client. The most popular client I think is MPDroid (https://play.google.com/store/apps/details?id=com.namelessdev.mpdroid), and this one had Widgets (homescreen AND lockscreen!) which work perfectly.
If you use spotify however, you’re stuck with the WebUI. Maybe this will change in future releases 
I hope you mean the Volumio Spotify Share App (https://volumio.org/volumio-android-apps/):
Its (as far as i know) the WebUI as an App with the extra function that you can send spotify music to your volumio.