I'm a guitarist and a software developer. I'd like to share an Android app I developed for music educators and practicing musicians, called Mozart's Friend.
Mozart's Friend includes an interactive music library with over 1,200 scales, modes and chords for every music key signature, complete with piano view and neck view for 6, 7 or 8-string guitar and 4, 5 or 6-string bass. Notes and intervals are labeled using music theory conventions, making Mozart's Friend a great companion for the composer or music student. One-touch audio demonstrations provide interactive ear training. Tunings for each instrument are fully user-definable.
Also included is a chromatic tuner and a programmable metronome with adjustable tones and intervallic beats, allowing you to quickly outline a chord to play along with. Transpose keys easily in a single swipe.
And finally, a one-touch backup band! The new Jam Tracks feature allows you to simply choose your musical style and you're up and running. Adjust the tempo and key with the friendly controls.
Mozart's Friend was designed to be simple, intuitive, powerful and efficient. At just 0.74 MB, you'll be hard-pressed to find a more powerful tool with such a small footprint. Mozart's Friend does not save nor send any user information, contains no ads and is absolutely Free.
Cheers,
-James
https://play.google.com/store/apps/details?id=com.jameschin.android.mozartsfriend