Rhythmic Metronome

This ad-free metronome allows the entry of custom rhythms to help
musicians play in time when playing songs with complex rhythms.
Rhythms can be made up of whole notes down to sixteenth notes
(including dotted notes, triplets, and ties) and rests of similar duration.
Time signatures can be specified to accentuate the clicks on the
downbeat and slightly accentuate every second beat (or third beat in
e.g., 6/8 time).

The tempo can be entered with a keyboard, selected among a drop-down list
of Italian tempo markings, or adjusted with buttons.

The rhythm and tempo can be saved in the application's memory.
The rhythm can also be copied to and pasted from the clipboard.
Go to the import/export screen (accessed through the big "floppy disc"
button icon) for this.

This metronome is audio-only and does not provide "visual clicks".

An advanced entry mode (reached by clicking on the "keyboard" icon on the
keyboard) allows for the entry of notes, rests and time signatures of
arbitrary duration.
E.g.,: Enter "n1/32" for a thirty-second note, "n3/64" for a dotted
thirty-second note, "n1/7" for a septuplet (seven notes in the time of
one); "r1/64" for a sixty-fourth rest;
"t7/4" for a 7-over-4 time signature.
It is also possible to group notes with parenthesis.
Individual notes and rests and groups can be played multiple times by
appending an asterisk and a number.
E.g.,: "(n1/2n1/4*2)*3" would play three times:
half-note, quater-note, quater-note.

Copyright 2014, IBM Corp.
Copyright 2018, Robert R. Enderlein.

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Known bugs:

The rhythm entry field does not allow moving the cursor by tapping,
making selections, or copy/pasting. Use the arrow keys on the keyboard to
move. Use the import/export screen (accessed
through the big "floppy disc" button icon) to copy or paste.

If the application sleeps for too long, the rhythm entry might be replaced
by "x". I suggest you save your rhythms often, and reload them if that
happens.

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Source code is available at:

https://github.com/robertre2/ch.e7n.metronome

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Attributions:

The metronome click soundtrack is from soundbible.com "Metronome",
recorded by Mike Koenig, license: Creative commons attribution 3.0.

The musical note images where generated with Lilypond (www.lilypond.org).

Some of the code was based on Periklis Ntanasis's BeatKeeper
(https://github.com/MasterEx/BeatKeeper). License: UNLICENSE.

Some of the code was based on Maarten Pennings's tutorial for
creating a custom keyboard
(http://www.fampennings.nl/maarten/android/09keyboard/index.htm).
Licensed under Apache License 2.0.

The Italian tempo markings where taken from Wikipedia
(http://en.wikipedia.org/wiki/Tempo#Italian_tempo_markings)
under an Creative Commons Attribution-ShareAlike License.

Recent changes:
Updated targetSdk to version 28.