Now there is some of the serious apps that can import midi but SunVox /FL Studio Mobile can and there is some Piano applications that can and probably some midi composing apps. Which brings me to another point TabMaster shows only regular notes and the Guitar tablature but for example the app midiSheetMusic ( free app ) can read midi files and you can see how it is played on the piano keyboard and transfer/study it and so use it in any appplication.So if you are stuck for inspiration or just needs notes for a song this application can help you...Or wonder of wonders... learn a song!
Also used it in combination with the GuitarPro app as it is possible to compose in GuitarPro and then use TabMaster to transform into Midi.
There is some other apps for guitar that works on the same principle, downloading guitar tablature directly from the internet just talking about this one as it is the one that I used and it works good for me.Also found it strange that it does not seem to be a similar application for piano at least did not find any after looking for awhile...
Just some thoughts that may be helpful?