最近有一個研究方向岳掐，在java里把python的noteSequence轉(zhuǎn)成midi凭疮，在網(wǎng)上找了很多文章饭耳，大部分都是介紹如何把midi文件轉(zhuǎn)成MidiEvent或者note的，好不容易找到了把noteSequence轉(zhuǎn)成midi的方法执解，記錄下來寞肖。

我做的測試時把midi轉(zhuǎn)成notes json，再把note json轉(zhuǎn)成midi衰腌。midi轉(zhuǎn)note就不多說了新蟆，網(wǎng)上很多相關文章，主要說一下note轉(zhuǎn)midi右蕊。

private static final String PATH1 = Environment.getExternalStorageDirectory().getPath() + File.separator + "xxx";
File fileDir;
private void test(){
        // 1. Open up a MIDI file
        fileDir = new File(PATH1);
        if (!fileDir.exists() && !fileDir.mkdirs()) {
        }
        File output = new File(fileDir.getAbsolutePath(),"example.mid");
        // 1. Create some MidiTracks
        MidiTrack tempoTrack = new MidiTrack();
        MidiTrack noteTrack = new MidiTrack();
        MidiTrack leftNoteTrack = new MidiTrack();

        // 2. Add events to the tracks
        // 2a. Track 0 is typically the tempo map
        TimeSignature ts = new TimeSignature();
        ts.setTimeSignature(4, 3, TimeSignature.DEFAULT_METER, TimeSignature.DEFAULT_DIVISION);

        Tempo t = new Tempo();
        t.setBpm(128);
        tempoTrack.insertEvent(ts);
        tempoTrack.insertEvent(t);

        SharedPreferences preferences = getSharedPreferences("SPF",MODE_PRIVATE);
        String leftJson = preferences.getString("leftJson","");
        String rightJson = preferences.getString("rightJson","");
        List<MSequence> leftList = JsonUtilCustomer.getParses(leftJson,MSequence.class);
        List<MSequence> rightList = JsonUtilCustomer.getParses(rightJson,MSequence.class);
        for (MSequence rightSequence : rightList) {
            NoteOn on = new NoteOn(rightSequence.getTick(),rightSequence.getChannel(),
                    rightSequence.getPitch(),rightSequence.getVelocity());
            NoteOff off = new NoteOff(rightSequence.getTick() + rightSequence.getDuration(),rightSequence.getChannel(),
                    rightSequence.getPitch(),rightSequence.getVelocity());
            noteTrack.insertEvent(on);
            noteTrack.insertEvent(off);
        }

        for (MSequence leftSequence : leftList) {
            NoteOn on = new NoteOn(leftSequence.getTick(),leftSequence.getChannel(),
                    leftSequence.getPitch(),leftSequence.getVelocity());
            NoteOff off = new NoteOff(leftSequence.getTick() + leftSequence.getDuration(),leftSequence.getChannel(),
                    leftSequence.getPitch(),leftSequence.getVelocity());
            leftNoteTrack.insertEvent(on);
            leftNoteTrack.insertEvent(off);
        }

        // It's best not to manually insert EndOfTrack events; MidiTrack will
        // call closeTrack() on itself before writing itself to a file

        // 3. Create a MidiFile with the tracks we created
        ArrayList<MidiTrack> tracks = new ArrayList<MidiTrack>();
        tracks.add(tempoTrack);
        tracks.add(noteTrack);
        tracks.add(leftNoteTrack);

        MidiFile midi = new MidiFile(MidiFile.DEFAULT_RESOLUTION, tracks);

        // 4. Write the MIDI data to a file
        try
        {
            midi.writeToFile(output);
        }
        catch(IOException e)
        {
            System.err.println(e);
        }
}