自己创作音乐的BeatBox！

import java.awt.*; import javax.swing.*; import javax.sound.midi.*; import java.util.*; import java.awt.event.*; 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(){ theFrame=new JFrame("Cyber 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("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(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); }//循环结束 setUpMidi(); theFrame.setBounds(50, 50, 300, 300); theFrame.pack(); theFrame.setVisible(true); }//关闭方法 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<15;j++){ JCheckBox jc=(JCheckBox) checkboxList.get(j+(16*i)); if(jc.isSelected()){ trackList[j]=key; }else{ trackList[j]=0; } }//关闭内部循环 makeTracks(trackList); track.add(makeEvent(176,1,127,0,16)); }//关闭外部循环 track.add(makeEvent(192,9,1,0,15)); try{ sequencer.setSequence(sequence); sequencer.setLoopCount(4); sequencer.start(); sequencer.setTempoInBPM(120); }catch(Exception e){e.printStackTrace();} }//关闭buildTrackAndStart方法 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*0.97)); } } 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+1)); } } } 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(Exception e){e.printStackTrace();} return event; } }