groove.java

用JAVA实现录音机功能

    public void close() {
        if (startB.getText().startsWith("Stop")) {
            startB.doClick(0);
        }
        if (sequencer != null) {
            sequencer.close();
        }
        sequencer = null;
    }


    private JButton makeButton(String bName, Color c) {
        JButton b = new JButton(bName);
        b.setBackground(c);
        b.addActionListener(this);
        return b;
    }


    private void buildTrackThenStartSequencer() {
        Sequence sequence = null;
        try {
           sequence = new Sequence(Sequence.PPQ, 4);
        } catch (Exception ex) { ex.printStackTrace(); }
        track = sequence.createTrack();
        createEvent(PROGRAM, 9, 1, 0);
        for (int i = 0; i < data.size(); i++) {
            Data d = (Data) data.get(i);
            for (int j = 0; j < d.staff.length; j++) {
                if (d.staff[j].equals(Color.black)) {
                     createEvent(NOTEON, 9, d.id, j); 
                     createEvent(NOTEOFF, 9, d.id, j+1); 
                }
            }
        }
        // so we always have a track from 0 to 15.
        createEvent(PROGRAM, 9, 1, 15);

        // set and start the sequencer.
        try {
            sequencer.setSequence(sequence);
        } catch (Exception ex) { ex.printStackTrace(); }
        sequencer.start();
        sequencer.setTempoInBPM(tempoDial.getTempo());
    }


    private void presetTracks(int num) {

        final int ACOUSTIC_BASS = 35;
        final int ACOUSTIC_SNARE = 38;
        final int HAND_CLAP = 39;
        final int PEDAL_HIHAT = 44;
        final int LO_TOM = 45;
        final int CLOSED_HIHAT = 42;
        final int CRASH_CYMBAL1 = 49;
        final int HI_TOM = 50;
        final int RIDE_BELL = 53;

        clearTable();

        switch (num) {
            case 0 : for (int i = 0; i < 16; i+=2) {
                         setCell(CLOSED_HIHAT, i); 
                     }
                     setCell(ACOUSTIC_SNARE, 4);
                     setCell(ACOUSTIC_SNARE, 12);
                     int bass1[] = { 0, 3, 6, 8 };
                     for (int i = 0; i < bass1.length; i++) {
                         setCell(ACOUSTIC_BASS, bass1[i]); 
                     }
                     break;
            case 1 : for (int i = 0; i < 16; i+=4) {
                         setCell(CRASH_CYMBAL1, i); 
                     }
                     for (int i = 0; i < 16; i+=2) {
                         setCell(PEDAL_HIHAT, i); 
                     }
                     setCell(ACOUSTIC_SNARE, 4);
                     setCell(ACOUSTIC_SNARE, 12);
                     int bass2[] = { 0, 2, 3, 7, 9, 10, 15 };
                     for (int i = 0; i < bass2.length; i++) {
                         setCell(ACOUSTIC_BASS, bass2[i]); 
                     }
                     break;
            case 2 : for (int i = 0; i < 16; i+=4) {
                         setCell(RIDE_BELL, i); 
                     }
                     for (int i = 2; i < 16; i+=4) {
                         setCell(PEDAL_HIHAT, i); 
                     }
                     setCell(HAND_CLAP, 4);
                     setCell(HAND_CLAP, 12);
                     setCell(HI_TOM, 13);
                     setCell(LO_TOM, 14);
                     int bass3[] = { 0, 3, 6, 9, 15 };
                     for (int i = 0; i < bass3.length; i++) {
                         setCell(ACOUSTIC_BASS+1, bass3[i]); 
                     }
                     break;
            default :
        }
        table.tableChanged(new TableModelEvent(dataModel));
    }


    private void setCell(int id, int tick) {
        for (int i = 0; i < data.size(); i++) {
            Data d = (Data) data.get(i);
            if (d.id == id) {
                d.staff[tick] = Color.black;
                break;
            }
        }
    }


    private void clearTable() {
        for (int i = 0; i < data.size(); i++) {
            Data d = (Data) data.get(i);
            for (int j = 0; j < d.staff.length; j++) {
                d.staff[j] = Color.white;
            }
        }
    }


    private void createEvent(int type, int chan, int num, long tick) {
        ShortMessage message = new ShortMessage();
        try {
            message.setMessage(type, chan, num, velocity); 
            MidiEvent event = new MidiEvent( message, tick );
            track.add(event);
        } catch (Exception ex) { ex.printStackTrace(); }
    }


    public void meta(MetaMessage message) {
        if (message.getType() == 47) {  // 47 is end of track
            if (loopB.getBackground().equals(Color.gray)) {
                if (sequencer != null && sequencer.isOpen()) {
                    sequencer.start();
                    sequencer.setTempoInBPM(tempoDial.getTempo());
                }
            } else {
                startB.setText("Start");
            }
        }
    }


    public void actionPerformed(ActionEvent e) {
        Object object = e.getSource();
        if (object instanceof JComboBox) {
            presetTracks(((JComboBox) object).getSelectedIndex());
            if (startB.getText().startsWith("Stop")) {
                sequencer.stop();
                buildTrackThenStartSequencer();
            }
        } else if (object instanceof JButton) {
            JButton b = (JButton) object;
            if (b.equals(startB)) {
                if (b.getText().startsWith("Start")) {
                    buildTrackThenStartSequencer();
                    b.setText("Stop");
                } else {
                    sequencer.stop();
                    b.setText("Start");
                }
            } else if (b.equals(loopB)) {
                b.setSelected(!b.isSelected());
                if (loopB.getBackground().equals(Color.gray)) {
                    loopB.setBackground(getBackground());
                } else {
                    loopB.setBackground(Color.gray);
                }
            } else if (b.getText().startsWith("Clear")) {
                clearTable();
                table.tableChanged(new TableModelEvent(dataModel));
            }
        }
    }


    /**
     * Storage class for instrument and musical staff represented by color.
     */
    class Data extends Object {
        String name; int id; Color staff[] = new Color[16];
        public Data(String name, int id) {
            this.name = name;
            this.id = id;
            for (int i = 0; i < staff.length; i++) {
                staff[i] = Color.white;
            }
        }
    }


    public static void main(String args[]) {
        final Groove groove = new Groove();
        JFrame f = new JFrame("Rhythm Groove Box");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        f.getContentPane().add("Center", groove);
        f.pack();
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        int w = 640;
        int h = 440;
        f.setLocation(screenSize.width/2 - w/2, screenSize.height/2 - h/2);
        f.setSize(w, h);
        f.show();
        groove.open();
    }
}