Swing运用：音乐播放器
16×16的乐器组合，可勾选不同组合播放乐音。
勾选后按下start键即可循环播放，按下stop键即可停止；
package a新音乐播放器;
import javax.sound.midi.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.util.ArrayList;
public class BeatBox {
JPanel mainPanel;
//把checkbox存储在ArrayList中
ArrayList<JCheckBox> checkboxList;
Sequencer sequencer;
Sequence sequence;
Track track;
JFrame theFrame;
//设置乐器名称
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"};
//乐器在Java中对应的关键字
int[] instruments = {
35,42,46,38,49,39,50,60,70,72,64,56,58,47,67,63};
//main（）函数
public static void main(String[] args) {
new BeatBox().buildGUI();
}
//创建GUI
public void buildGUI()
{
theFrame = new JFrame("Cyber BeatBox");
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//背景
BorderLayout layout = new BorderLayout();
JPanel background = new JPanel(layout);
//设置面板上摆设组件的空白边缘
background.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
checkboxList = new ArrayList<JCheckBox>();
Box buttonBox = new Box(BoxLayout.Y_AXIS);//用BoxLayout进行布局
//start按钮，开始循环播放
JButton start = new JButton("Start");
start.addActionListener(new MyStartListener());
buttonBox.add(start);
//stop按钮，停止播放
JButton stop = new JButton("Stop");
stop.addActionListener(new MyStopListener());
buttonBox.add(stop);
//调高节奏
JButton upTempo = new JButton("Tempo Up");
stop.addActionListener(new MyUpTempoListener());
buttonBox.add(upTempo);
//调低节奏
JButton downTempo = new JButton("Tempo Down");
downTempo.addActionListener(new MyDownTempoListener());
buttonBox.add(downTempo);
//将乐器名字按照BoxLayout进行排列
Box nameBox = new Box(BoxLayout.Y_AXIS);
for(int i=0;i<16;i++)
{
nameBox.add(new Label(instrumentNames[i]));
}
//将4个按钮设置在背景的右边，将乐器名字设置在左边
background.add(BorderLayout.EAST,buttonBox);
background.add(BorderLayout.WEST,nameBox);
//把设置好的背景添加到JFrame对象中
theFrame.getContentPane().add(background);
//按GridLayout的排列方式设置16*16的格子
GridLayout grid = new GridLayout(16,16);
grid.setVgap(1);//设置垂直间距
grid.setHgap(2);//设置水平间距
//将16*16的勾选格加到背景中
mainPanel = new JPanel(grid);
background.add(BorderLayout.CENTER,mainPanel);
//创建checkbox组，设定未勾选的为false并加到ArrayList和面板上
for(int i=0;i<256;i++)
{
JCheckBox c = new JCheckBox();
c.setSelected(false);
checkboxList.add(c);
mainPanel.add(c);
}
setUpMidi();
//基操
theFrame.setBounds(50,50,300,300);
theFrame.pack();
theFrame.setVisible(true);
}
//setUPMidi（）方法是一般的Midi设置程序代码
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();
}
}
//开始播放的方法
public void buildTrackAndStart(){
int[] trackList =null;//储存乐器值
//消掉旧的track并创建一个新的
sequence.deleteTrack(track);
track = sequence.createTrack();
//对16个乐器都执行一遍
for(int i=0;i<16;i++)
{
trackList = new int[16];
int key = instruments[i];//乐器关键字
//对每一拍都执行一次
for(int j=0;j<16;j++)
{
//以列为单位逐个遍历
JCheckBox jc = (JCheckBox) checkboxList.get(j+(16*i));
//如果勾选了，就加到数组中，否则补0
if(jc.isSelected()){
trackList[j] = key;
}else{
trackList[j] = 0;
}
}
//创建乐器事件并加到track中
makeTracks(trackList);
track.add(makeEvent(176,1,127,0,16));
}
//确保第16拍有事件，从而实现循环播放
track.add(makeEvent(192,9,1,0,15));
try{
sequencer.setSequence(sequence);
sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);//指定为无穷次数
sequencer.start();//开始播放
sequencer.setTempoInBPM(120);
}catch (Exception e){
e.printStackTrace();
}
}
//四个内部类，分别实现4个按钮的接听
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+1));
}
}
}
//1-4个参数是给信息用的，tick是何时播放信息
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();
}
//返回事件
return event;
}
public class MyReadInListener implements ActionListener{
public void actionPerformed(ActionEvent a){
boolean[] checkboxState = null;
try{
FileInputStream fileIn = new FileInputStream(new File("Checkbox.ser"));
ObjectInputStream is =new ObjectInputStream(fileIn);
checkboxState = (boolean[])is.readObject();
}catch (Exception e){
e.printStackTrace();
}
for(int i=0;i<256;i++)
{
JCheckBox check = (JCheckBox) checkboxList.get(i);
if(checkboxState[i]){
check.setSelected(true);
}else{
check.setSelected(false);
}
}
sequencer.stop();
buildTrackAndStart();
}
}
}
