A lot of time since the last post. Let me announce a new port of VMPK, for Android (4.x) devices. It is available in Google Play.
There are two apps, a paid version (0.5€) and a free one (gratis) with a small advertisement. It is not based on Qt, and it is not open source. It is a Java port rewritten
from scratch using the native Android MIDI synthesizer and native
Android themes. But on the other hand, is quite similar to the old N9
port, as you can see in the following screenshots, but with several additional features.
Being mostly a Java app, it includes some C code. The internal MIDI synthesizer is Android's "Sonivox EAS", which is part of AOS. The library is included in all recent Android versions, but it is not a public API, so I've compiled the library with a customized configuration and different features resulting a smaller binary and included it in the APK along with some other native code, mainly opensl_stream by Peter Brinkmann for interfacing the synth with Android's OpenSL ES audio output. An interesting aspect of the synth is the embedded GM soundfont using very small amount of memory, and not needing external data files.
Some features are: ipMIDI compatibility (MIDI OUT only) using UDP multicast and Wireless network. Accelerometer driven sliders for velocity, controllers and bender (like the N9 port), configurable number of keys and initial key, among other goodies.