Head_First_Java之BeatBox.java

以你之姓@ 2022-06-08 01:53 177阅读 0赞

import javax.swing.*;
    import java.awt.*;
    import javax.sound.midi.*;
    import java.util.*;//ArrayList
    import java.awt.event.*;
    
    public class BeatBox {
    	JPanel mainPanel;
    	ArrayList
       
         checkboxList;//把checkbox存储在ArrayList中
    	Sequencer sequencer;
    	Sequence sequence;
    	Track track;
    	JFrame theFrame;
    	
    	String[] instrumentNames={"Bass Drum","Close Hi-Hat","Open Hi-Hat","Acounstic snare","Crash Cymbal","Hand Clap",
    			"High Tom","Hi Bongo","Maracas","Whistle","Low conga","Cowbell","Vibraslap","Low-mid Tom","High Agogo","Open Hi Conga"};
    	//乐器的名称，以String的array维护
    	int[] instruments={35,42,46,38,49,39,50,60,70,72,64,56,58,47,67,63};
    	//实际的乐器关键字，例如说35就代表Bass Drum
    	
    	public static void main(String[] args){
    		BeatBox beatBox=new BeatBox();
    		beatBox.buildGUI();
    	}
    	
    	public void buildGUI(){
    		theFrame=new JFrame("Cyber BeatBox");
    		theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    		JPanel background=new JPanel(new BorderLayout());//JPanel面板需要添加BorderLayout布局管理器
    		background.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));//设置面板上摆设组件时的空白边缘
    		
    		
    		checkboxList=new ArrayList
        
         ();
    		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);
    		
    		
    		
    		GridLayout grid=new GridLayout(16,16);//布局管理器之网格布局GridLayout (16*16的网格分布）
    		grid.setVgap(1);//设置垂直间距
    		grid.setHgap(5);//设置水平间距
    		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);          //从左至右，从上至下
    		}
    		setUpMidi();
    		
    		theFrame.getContentPane().add(background);
    		//theFrame.setBounds(50,50,100,100);
    		theFrame.pack();//若是已定义的setBound()范围太小，窗口自动调整
    		theFrame.setVisible(true);
    	}
    		
    		public void setUpMidi(){  //midi音频
    			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();//清除旧的track，重建一个新的
    		
    		for(int i=0;i<16;i++){
    			trackList=new int[16];
    			
    			int key=instruments[i];  //设定代表乐器的关键字
    			
    			for(int j=0;j<16;j++){
    				
    				JCheckBox jc=(JCheckBox) checkboxList.get(j+(16*i));
    				if(jc.isSelected()){   //判断选取的状态
    					trackList[j]=key;
    				}else{
    					trackList[j]=0;
    				}
    			}
    			
    			makeTracks(trackList);					
    			//track.add(makeEvent(176,1,127,0,16));//不会做任何事情，只是让我们知道有音符在播放
    		}
    		
    		track.add(makeEvent(192,9,1,0,15));//确拍保第16拍有事件，否则BeatBox不会重复播放
    		try{
    			sequencer.setSequence(sequence);
    			sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);//指定无穷的重复次数
    			sequencer.start();
    			sequencer.setTempoInBPM(120);
    		}catch(Exception 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*2));//节奏速度
    		}
    	}
    	public class MyDownTempoListener implements ActionListener{
    		public void actionPerformed(ActionEvent a){
    			float tempoFactor=sequencer.getTempoFactor();
    			sequencer.setTempoFactor((float)(tempoFactor*0.5));
    		}
    	}
    	
    	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);//tick表示拍
    		}catch(Exception e){e.printStackTrace();}
    		return event;
    	  }
    
    }