老师说是程序不完整 少打了括号什么的 但是好像没有什么少的 :-（
import java.awt.BorderLayout;
import java.awt.Checkbox;
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.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={"bess brum","closed hi hat","open hi hat","acoustic snare","crash Cymbal","hand clap","hight tom","hi bongo","maracas","whistle",
"low conga","cowbell","vibrasslap","low-mid tom","hight Agogo","open hi conga",};
int[] instruments={35,42,46,38,49,39,50,60,70,76,64,56,58,47,67,63};

public static void main(String[] args) {
// TODO Auto-generated method stub
new BeatBox().buildGUI();
}
public void buildGUI(){
theFrame=new JFrame("BeatBox");
theFrame.setDefaultCloseOperation(JFrame .EXIT_ON_CLOSE);
BorderLayout layout=new BorderLayout();
JPanel background=new JPanel(layout);
background.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

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

JButton start = new JButton("开始");
start.addActionListener(new MyStartListen());
buttonBox.add(start);

JButton stop = new JButton("停止");
stop.addActionListener(new MystopListen());
buttonBox.add(stop);

JButton tempo= new JButton("节奏增加");
tempo.addActionListener(new MytempoListen());
buttonBox.add(tempo);

JButton dtempo= new JButton("节奏减少");
dtempo.addActionListener(new MydteopoListen());
buttonBox.add(dtempo);

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(1);
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 buildTrackAndStrat(){
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;