package test;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

import javax.sound.midi.InvalidMidiDataException;
import javax.sound.midi.MidiEvent;
import javax.sound.midi.MidiSystem;
import javax.sound.midi.Sequence;
import javax.sound.midi.Sequencer;
import javax.sound.midi.ShortMessage;
import javax.sound.midi.Track;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class BeatBox {
JPanel mainPanel;
ArrayList<JCheckBox> checkboxList;
Sequencer sequencer;
Sequence sequence;
Track track;
JFrame theFrame;

String[] instrumentNames={
"Bass Drum","Closed Hi-Hat","Open Hi-Hat","Acoustic Snare",
"Crash Cymbal","Hand Clap","High Tom","Hi Bongo",
"Maracas","Whistle","Low Conga","Cowbell",
"Vibraslap","Low-mid Tom","High Agogo","Open Hi Conga"};
int[] instruments={35,42,46,38,49,39,50,60,70,72,64,56,58,47,67,63};

public static void main(String[] args) {
new BeatBox().buildGUI();
}

public void buildGUI(){
// the title for the frame
theFrame = new JFrame("Cyber BeatBox");
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BorderLayout layout = new BorderLayout();
JPanel background = new JPanel(layout);
//设置面板上摆设组件时的空白边缘
background.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));

checkboxList = new ArrayList<JCheckBox>();
Box buttonBox = new Box(BoxLayout.Y_AXIS);

JButton start = new JButton("Start");
start.addActionListener(new MyStartListener());
buttonBox.add(start);

JButton stop = new JButton("Stop");
stop.addActionListener(new MyStopListener());
buttonBox.add(stop);

JButton upTempo = new JButton("Tempo up");
upTempo.addActionListener(new MyUpTempoListener());
buttonBox.add(upTempo);

JButton downTempo = new JButton("Tempo down");
downTempo.addActionListener(new MyDownTempoListener());
buttonBox.add(downTempo);

Box nameBox = new Box(BoxLayout.Y_AXIS);
for(int i=0;i<16;i++){
nameBox.add(new Label(instrumentNames[i]));
}

background.add(BorderLayout.EAST,buttonBox);
background.add(BorderLayout.WEST,nameBox);

theFrame.getContentPane().add(background);

GridLayout grid = new GridLayout(16,16);
grid.setVgap(2);
grid.setHgap(2);
mainPanel = new JPanel(grid);
background.add(BorderLayout.CENTER,mainPanel);

for(int i=0;i<256;i++){
JCheckBox c = new JCheckBox();
c.setSelected(false);
checkboxList.add(c);
mainPanel.add(c);
}

setUpMidi();

theFrame.setBounds(50,50,300,300);
theFrame.pack();
theFrame.setVisible(true);
}

public void setUpMidi(){
try {
sequencer = MidiSystem.getSequencer();
sequencer.open();
sequence = new Sequence(Sequence.PPQ,4);
track = sequence.createTrack();
sequencer.setTempoInBPM(120);
} catch (Exception e) {
e.printStackTrace();
}
}

public void buildTrackAndStart(){
int[] trackList = null;

sequence.deleteTrack(track);
track = sequence.createTrack();

for(int i=0;i<16;i++){
trackList = new int[16];

int key = instruments[i];
for(int j=0;j<16;j++){
JCheckBox jc = (JCheckBox)checkboxList.get(j + (16*i));
if( jc.isSelected() ){
trackList[j] = key;
}else{
trackList[j] = 0;
}
}

makeTracks(trackList);
track.add(makeEvent(176,1,127,0,16));
}

track.add(makeEvent(192,9,1,0,15));

try {
sequencer.setSequence(sequence);
sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);
sequencer.start();
sequencer.setTempoInBPM(20);
} catch (InvalidMidiDataException e) {
e.printStackTrace();
}

}

public class MyStartListener implements ActionListener{
public void actionPerformed(ActionEvent a){
buildTrackAndStart();
}
}

public class MyStopListener implements ActionListener{
public void actionPerformed(ActionEvent a){
sequencer.stop();
}
}

public class MyUpTempoListener implements ActionListener{
public void actionPerformed(ActionEvent a){
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * 1.03));
}
}

public class MyDownTempoListener implements ActionListener{
public void actionPerformed(ActionEvent a){
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * .97));
}
}

public void makeTracks(int[] list){
for(int i=0;i<16;i++){
int key= list[i];

if(key != 0){
track.add(makeEvent(144,9,key,100,i));
track.add(makeEvent(128,9,key,100,i++));
}
}
}

public MidiEvent makeEvent(int comd,int chan,int one,int two,int tick){
MidiEvent event = null;

try {
ShortMessage a = new ShortMessage();
a.setMessage(comd,chan,one,two);
event = new MidiEvent(a,tick);
} catch (InvalidMidiDataException e) {
e.printStackTrace();
}
return event;
}

}

java 示例