CT-Gui-Ftor, CT-Synth

GUI toolkit for the Linux desktop and for Android tablets, running Android 4.4 or higher.
Included a demo project, a synthesizer.
CT-synth
Attached to MIDI keyboard

Info about building and installing: README

Source code:
CT-ftor-combo.tar.gz (date: april, 2016)

Apk file (to download directly to your device):
CT_Synth-release.apk
NB! You will need at least Android version 4.4, aka Kitkat, as this is the first version that provides low audio-latency. Don't forget to enable Unknown Sources, in the Security settings of your device.

In order to connect a MIDI keyboard (via an OTG cable), the tablet must have USB-host capability.