How to clear what I draw in a component?

Question

Hi, I am doing some drawing in a component, and I want to click the button, then what I draw will clear immediately, so how do I do that?

Answer 1

hi, I can not give you a shor code
but this is the excutatble code, my intention is to click the stop button, the music will stop playing and the waveform will be cleared, but till not I do not know how to do it, thanks for your help..
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package display513;
import java.io.*;
import java.util.Vector;
import java.util.Deque;
import java.util.Scanner;
import java.util.LinkedList;
import java.net.URL;
import javax.sound.sampled.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Line2D;
import javax.swing.ImageIcon;
import javax.swing.filechooser.FileNameExtensionFilter;
* @author wangyue
public class demo {
    public demo()
        javax.swing.SwingUtilities.invokeLater(new Runnable()
            public void run()
                ShowWaveForm();
    private void ShowWaveForm()
        JFrame frame = new JFrame("Real-time audio beat tracking");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JComponent contentPane = new Pane();
        contentPane.setOpaque(true);
        frame.setContentPane(contentPane);//����add���� ����������������
        frame.pack();
        frame.setResizable(false);//false
        frame.setVisible(true);
    public static void main(String[] args)
        demo mydemo = new demo();
class Pane extends JPanel
  //public field .....................................
  private float FONT_SIZE = 20;
  //String name for button
  private static final String openString = "Open file";
  private static final String playString = "play only";
  private static final String play_trackString = "play&track";
  private static final String play_beatsString = "play beats only";
  private static final String pause_resumeStrig = "pause";
  private static final String stopString = "stop";
  private static final String save_beatsString = "save beats";
  private static final String quitString ="quit";
  //********************************button component************************
  private JButton openButton;
  private JButton playButton;
  private JButton play_trackButton;
  private JButton play_beatsButton;
  private JButton pause_resumeButton;
  private JButton stopButton;
  private JButton save_beatsButton;
  private JButton quitButton;
  //********************************button component************************
  //����������
  private Vector<Double> samples = new Vector<Double>(1024);
  private ImageIcon logoIcon = new ImageIcon("logo.jpg","the logo");   
  private static boolean isPlay ;
  FilenameFilter wavFilter = new WavFilter();
  private JLabel logolabel;
  private JTextField beatfield;
  private JPanel waveformpanel;
  private JPanel logopanel ;
  final  private JFileChooser chooser;
  private String filename;
  private static boolean track_flag = false;
  private static boolean notkill ;
  public Pane()
    super(new BorderLayout());
    isPlay = false;
    notkill = true;
    track_flag = false;
    openButton = new JButton(openString);
    openButton.addActionListener(new openListener());
    //openButton.setBorder(BorderFactory.createEmptyBorder(14,14,14,14));
    openButton.setSize(0,10);
    playButton = new JButton(playString);
    playButton.addActionListener(new playListener());   
    play_trackButton = new JButton(play_trackString);
    play_trackButton.addActionListener(new play_trackListener());
    play_beatsButton = new JButton(play_beatsString);
    play_beatsButton.addActionListener(new play_beatsListener());
    pause_resumeButton = new JButton(pause_resumeStrig);
    pause_resumeButton.addActionListener(new pause_resumeListener());
    stopButton = new JButton(stopString);
    stopButton.addActionListener(new stopListener());
    save_beatsButton = new JButton(save_beatsString);
    save_beatsButton.addActionListener(new save_beatsListener());
    quitButton = new JButton(quitString);
    quitButton.addActionListener(new quitListener());
    beatfield = new JTextField(1);
    JPanel lowerpane = new JPanel(new BorderLayout());
    lowerpane.add(beatfield, BorderLayout.CENTER);
    TitledBorder fieldOutsideBorder  = BorderFactory.createTitledBorder("Real Time Tracked Beats");
    fieldOutsideBorder.setTitleFont(fieldOutsideBorder.getTitleFont().deriveFont(FONT_SIZE));
    Border fieldInsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
    lowerpane.setBorder(BorderFactory.createCompoundBorder(fieldOutsideBorder,fieldInsideBorder));
    waveformpanel = new WaveformPanel();
    waveformpanel.setOpaque(true);
    JPanel upperpane = new JPanel(new BorderLayout());
    upperpane.add(waveformpanel, BorderLayout.CENTER);
    TitledBorder waveOutsideBorder  = BorderFactory.createTitledBorder("Music Signal");
    waveOutsideBorder.setTitleFont(waveOutsideBorder.getTitleFont().deriveFont(FONT_SIZE));
    Border waveInsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
    upperpane.setBorder(BorderFactory.createCompoundBorder(waveOutsideBorder,waveInsideBorder));
    //waveformpanel.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
    // ������������panel ����button
    JPanel buttonpane = new JPanel();
  //  buttonpane.setLayout(new BoxLayout(buttonpane, BoxLayout.Y_AXIS));
    GridLayout gl = new GridLayout(9,1);
    gl.setVgap(25);
    buttonpane.setLayout(gl);   
    buttonpane.add(openButton);
    buttonpane.add(playButton);
    buttonpane.add(play_trackButton);
    buttonpane.add(play_beatsButton);
    buttonpane.add(pause_resumeButton);
    buttonpane.add(stopButton);
    buttonpane.add(save_beatsButton);
    buttonpane.add(quitButton);
    buttonpane.setBorder(BorderFactory.createEmptyBorder(20,20,5,5));
   // BorderFactory.createLineBorder(Color.BLUE, 5);
    //Border outterborder = BorderFactory.createEmptyBorder(20,18,5,5);
  //  Border innerborder  = BorderFactory.createLineBorder(Color.GRAY);
    //buttonpane.setBorder();
  //  buttonpane.setBorder(BorderFactory.createCompoundBorder(outterborder,innerborder));
    JPanel rightpane = new JPanel(new BorderLayout());
  //  rightpane.setSize(100, 100);
   // rightpane.add(upperpane,BorderLayout.NORTH);  
    rightpane.add(upperpane,BorderLayout.NORTH);
  //  rightpane.add(lowerpane, BorderLayout.SOUTH);
     rightpane.add(lowerpane);
    rightpane.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
    JPanel buttompane = new JPanel();
    buttompane.setLayout(new BoxLayout(buttompane, BoxLayout.LINE_AXIS));
    buttompane.add(buttonpane);
    buttompane.add(rightpane);
    logopanel = new JPanel(new BorderLayout());//fuck fuck   ��������������������
    JLabel logolabel = new JLabel(logoIcon);
    //logolabel.setIcon(logoIcon); //faint ����������������������������
    logopanel.add(logolabel);    
    // ����������������
   // add(logopanel, BorderLayout.SOUTH); 
    add(logopanel, BorderLayout.PAGE_START);
    add(buttompane, BorderLayout.CENTER);
      chooser = new JFileChooser();
         playButton.setEnabled(false);
         play_beatsButton.setEnabled(false);
         pause_resumeButton.setEnabled(false);
         play_trackButton.setEnabled(false);
         stopButton.setEnabled(false);
         save_beatsButton.setEnabled(false);
  }// end for Panel()
  public void setFilename(String filename)
       this.filename = filename;
  public String getFilename()
      return filename;
  class openListener implements ActionListener
        public void actionPerformed(ActionEvent e)
        //  int state = chooser.showOpenDialog(null);
         chooser.setCurrentDirectory(new File("D:\\"));
         FileNameExtensionFilter filter = new FileNameExtensionFilter("wav", "wav");
         chooser.setFileFilter(filter);
         int state = chooser.showOpenDialog(null);
         if(state == JFileChooser.APPROVE_OPTION)
             filename =  chooser.getSelectedFile().getName();
             setFilename(filename);
             playButton.setEnabled(true);
             play_trackButton.setEnabled(true);
             pause_resumeButton.setEnabled(false);
             stopButton.setEnabled(false);
             save_beatsButton.setEnabled(false);
             System.out.println("You chose to open this file: " + filename);
             else if(state == JFileChooser.CANCEL_OPTION)
                JOptionPane.showMessageDialog(null, "Canceled");
             else if(state == JFileChooser.ERROR_OPTION)
                JOptionPane.showMessageDialog(null, "Error!");
       //throw new UnsupportedOperationException("Not supported yet.");
  class playListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
         play_beatsButton.setEnabled(true);
         pause_resumeButton.setEnabled(true);
         stopButton.setEnabled(true);
         save_beatsButton.setEnabled(true);
        //����������������
         isPlay = true;
         new PlayThread(getFilename()).start();
            //throw new UnsupportedOperationException("Not supported yet.");
  class play_trackListener implements ActionListener
        public void actionPerformed(ActionEvent e)
            track_flag  = true;
            isPlay = true;
            new PlayThread(getFilename()).start();
            play_beatsButton.setEnabled(true);
            pause_resumeButton.setEnabled(true);
            stopButton.setEnabled(true);
            save_beatsButton.setEnabled(true);
  class play_beatsListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
            throw new UnsupportedOperationException("Not supported yet.");
  class pause_resumeListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
          //  throw new UnsupportedOperationException("Not supported yet.");
            if(isPlay)
                 isPlay = false;               
                 pause_resumeButton.setText("continue");
               //  System.out.println(isPlay);
            else
                  isPlay = true;
                  pause_resumeButton.setText("pause");
                //  System.out.println(isPlay);
  class stopListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
            //throw new UnsupportedOperationException("Not supported yet.");       
           // new PlayThread(getFilename()).start();
            //isPlay = false;
           // notkill = false;
  class save_beatsListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
            throw new UnsupportedOperationException("Not supported yet.");
  class quitListener implements ActionListener
        public void actionPerformed(ActionEvent e) {
          //  throw new UnsupportedOperationException("Not supported yet.");
           System.exit(0);
  class WaveformPanel extends JPanel implements ActionListener
      Timer timer;
      int speed = 100;//100
      int pause = 0;
      int nframe=0;
      int count=20;
      int pp=0;//������������
      double xpos=1.0;
  int[] pos= { 150,190,230,274,315,356,395,436,477,515,555,595,635,675,715,755,795,835,875,915,955,995,10,6,1076,1116,1155,1195,1235,1275
,1315,1355,1395,1434,1474,1514,1554,1594,1634,1673,1713,1753,1793,1833,1873,1913,1953,1993,2033,2073,2113,2153,2192,2232,2223,2322,2352,2392,2431,2471,2511,2551};
      public WaveformPanel()
         super(new BorderLayout());
         setPreferredSize(new Dimension(500, 400));
         timer = new Timer(speed, this);
         timer.setInitialDelay(pause);
         timer.start();
      public void actionPerformed(ActionEvent e)
        if (!isPlay && !notkill)
           // return;
        else
            repaint();
      public void paint(Graphics graph)
          Graphics2D g = (Graphics2D) graph;
          Dimension d = getSize();
          double gridWidth = d.getWidth();
          double gridHeight = d.getHeight();
          int gridWidthInt = new Double(gridWidth).intValue();
          int gridHeightInt = new Double(gridHeight).intValue();
          g.clearRect(0, 0, gridWidthInt, gridHeightInt);
          g.setColor(Color.red);
          ///g.fi
          int size = samples.size();//size ����������1600��������
         if(notkill = false)
            // get the visible area
            Rectangle clip = g.getClipBounds();
             // set a color you want for clearing
            g.setColor(getBackground());
            g.fillRect(clip.x, clip.y, clip.width, clip.height);
         else
              for (int index = 1; index < size - 1; index++)
                    Double s = samples.elementAt(index);   
                    double x1 = (new Integer(index + 1)).doubleValue() / 1024.0
                      * gridWidth;
                    double x2 = x1;
                    double y1 ;
                    double y2 ;
                    if( s.doubleValue()>900)
                        y1 =0.0;
                    else
                        y1 = 0.5 * gridHeight;
                    y2= 0.5 * gridHeight * (1 + s.doubleValue());
                 g.draw(new Line2D.Double(x1,y1,x2,y2));
class PlayThread extends Thread
     String filename;
     int index=0;
     int nframe=0;
     int[] pos= { 150,190,230,274,315,356,395,436,477,515,555,595,635,675,715,755,795,835,875,915,955,995,1076,1116,1155,1195,1235,1275
,1315,1355,1395,1434,1474,1514,1554,1594,1634,1673,1713,1753,1793,2392,2431,2471,2511,2551};     
     public PlayThread(String filename)
         this.filename = filename;
         samples = new Vector<Double>(1024);
     public void run()
        // isPlay = true;
         final byte[] buf = new byte[2];
         AudioInputStream ain = null;
         SourceDataLine line = null;
         try
             File sndFile = new File(filename);
             ain = AudioSystem.getAudioInputStream(sndFile);
             AudioFormat formatInfo = ain.getFormat();
             DataLine.Info info = new DataLine.Info(SourceDataLine.class, formatInfo);
             line = (SourceDataLine) AudioSystem.getLine(info);
             line.open(formatInfo);
         catch(Exception e)
             System.err.println(e.getMessage());
             isPlay = false;
             return ;
         try
            int sampleIndex = 0;
            int sampleRate = 512;
            int capacity = samples.capacity();
            line.start();
            //if(notkill)
            System.out.println(notkill);
                    while( ain.read(buf) != -1 && !notkill)// && notkill
                        if(isPlay)
                            // System.out.println(isPlay);
                             line.write(buf, 0,2);
                             if (sampleIndex == sampleRate)
                              double scale = new Short(getSample(buf)).doubleValue() / 32767.0;
                             //fuck ���������������� ����������  fuck fuck     
                              if(track_flag == true)
                                    if(pos[index] == nframe)
                                       samples.add(new Double(scale+1000));
                                       System.out.println(index);
                                       index++;
                                    else
                                    samples.add(new Double(scale));
                                else
                                    samples.add(new Double(scale));
                                  sampleIndex = 0;                
                                  nframe++;
                                 if (samples.size() == capacity)
                                     samples.remove(0);
                            sampleIndex++;
                        else
                            while(true)
                                //System.out.println(isPlay);//������ ������ ������������
                                //��������������
                               // int aa=1;
                              //  System.out.println("wang yue fighting");
                                Thread.sleep(500);
                                if(isPlay == true)
                                    break;
                                //else
         catch(Exception e)
             System.err.println(e.getMessage());
             isPlay = false;
             return ;
         line.drain();
         line.close();
         isPlay = false;
     }// end run method
     private short getSample(byte[] buf)
      short sample = 0x0000;
      short mask = 0x00ff;
      sample |= (mask & buf[1]);
      sample <<= 8;
      sample |= (mask & buf[0]);
      return sample;
}// end play thread
class WavFilter implements FilenameFilter {
    public boolean accept(File dir, String name) {
      return (name.endsWith(".wav"));
}