MiniMusicPlayer HFJ

[Brian Pianczk]

OK I have two sets of code here both, to me, look to be the same except for style differences. One I wrote from doing the section in the book MiniMusicPlayer. The other was a direct copy and paste MiniMusicPlayer3.
Mine doesn't work, it plays the track, but doesn't display the random rectangles. The copied and pasted code works.
I can't recognize the difference in the two codes,(myDrawPanel is named different in the two, but referenced the same way) I am curious if anyone else can see something I am not seeing?


Mine

import javax.sound.midi.*;
import java.io.*;
import javax.swing.*;
import java.awt.*;

public class MiniMusicPlayer {
	static JFrame f = new JFrame("My First Music Video");
	static MyDrawPanel1 ml;

	public static void main (String [] args) {
		MiniMusicPlayer mini = new MiniMusicPlayer();
		mini.go();
	}
	
	public void setUpGui() {
		ml = new MyDrawPanel1();
		f.setContentPane(ml);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.setBounds(30, 30, 300, 300);
		f.setVisible(true);
	}
	public void go() {
		setUpGui();
		
		try {
			Sequencer sequencer = MidiSystem.getSequencer();
			sequencer.open();
			sequencer.addControllerEventListener(ml, new int[] {127});
			Sequence seq = new Sequence(Sequence.PPQ, 4);
			Track track = seq.createTrack();
			
			int r = 0;
			for (int i = 0; i < 60; i += 4) {
				r = (int) ((Math.random() * 50) +1);
				track.add(makeEvent(144, 1, r, 100, i));
				track.add(makeEvent(176, 1, 127, 0, i));
				track.add(makeEvent(128, 1, r, 100, i + 2));
			}
			
			sequencer.setSequence(seq);
			sequencer.start();
			sequencer.setTempoInBPM(220);
			
		} catch (Exception ex) {ex.printStackTrace();}
	}
	
	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) {}
		return event;
	}
	
	class MyDrawPanel1 extends JPanel implements ControllerEventListener {
		boolean msg = false;
		
		public void controlChange(ShortMessage event) {
			msg = true;
			repaint();
		}
		
		public void paintCompenent (Graphics g) {
			if (msg) {
			
				Graphics2D g2 = (Graphics2D) g;
				
				int r = (int) (Math.random() * 250);
				int gr = (int) (Math.random() * 250);
				int b = (int) (Math.random() * 250);
				
				g.setColor(new Color(r, gr, b));
				
				int ht = (int) ((Math.random() * 120) + 10);
				int width = (int) ((Math.random() * 120) + 10);
				
				int x = (int) ((Math.random() * 40) + 10);
				int y = (int) ((Math.random() * 40) + 10);
				
				g.fillRect(x, y, ht, width);
				msg = false;
			}
		}
	}
}    

Copied version

     import javax.sound.midi.*;
    import java.io.*;
    import javax.swing.*;
    import java.awt.*;

    public class MiniMusicPlayer3
    {
       static JFrame f = new JFrame ( "My First Music Video" );
       static MyDrawPanel ml;
       
       public static void main ( String[] args )
       {
          MiniMusicPlayer3 mini = new MiniMusicPlayer3 (  );
          mini.go (  );
       }
       
       public void setUpGui (  )
       {
          ml = new MyDrawPanel (  );
          f.setContentPane ( ml );
		  f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          f.setBounds ( 30, 30, 300, 300 );
          f.setVisible ( true );
       }
       
       public void go (  )
       {
          setUpGui (  );
          
          try
          {
             Sequencer sequencer = MidiSystem.getSequencer (  );
             sequencer.open (  );
             sequencer.addControllerEventListener ( ml, new int[] { 127 } );
             Sequence seq = new Sequence ( Sequence.PPQ, 4 );
             Track track = seq.createTrack (  );
             
             int r = 0;
             for ( int i = 0; i < 60; i += 4 )
             {
                r = ( int ) ( ( Math.random (  ) * 50 ) + 1 );
                track.add ( makeEvent ( 144, 1, r, 100, i ) );
                track.add ( makeEvent ( 176, 1, 127, 0, i ) );
                track.add ( makeEvent ( 128, 1, r, 100, i + 2 ) );
             }
             
             sequencer.setSequence ( seq );
             sequencer.start (  );
          } catch ( Exception ex ) { ex.printStackTrace (  ); }
       }
       
       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 ) {  }
          
          return event;
       }
       
       class MyDrawPanel extends JPanel implements ControllerEventListener
       {
          boolean msg = false;
          
          public void controlChange ( ShortMessage event )
          {
             msg = true;
             repaint (  );
          }
          
          public void paintComponent ( Graphics g )
          {
             if ( msg )
             {
                Graphics2D g2 = ( Graphics2D ) g;
                
                int r = ( int ) ( Math.random (  ) * 255 );
                int gr = ( int ) ( Math.random (  ) * 255 );
                int b = ( int ) ( Math.random (  ) * 255 );
                
                g.setColor ( new Color ( r, gr, b ) );
                
                int ht = ( int ) ( ( Math.random (  ) * 120 ) + 10 );
                int width = ( int ) ( ( Math.random (  ) * 120 ) + 10 );
                
                int x = ( int ) ( ( Math.random (  ) * 40 ) + 10 );
                int y = ( int ) ( ( Math.random (  ) * 40 ) + 10 );
                
                g.fillRect ( x, y, ht, width );
                msg = false;
             }
          }
       }
    }
   

[Bartek Myszkowski]

class MiniMusicPlayer, line 66 - You override method paintCompenent instead of paintComponent
after correcting method name works fine for me

[Brian Pianczk]

Thank you! I looked over this code again and again. Even line by line and did not notice. Even when I pinpointed it to that bit of code.

Thanks again!

[Michael Dunn]

for future reference, had you done this

@Override//<---------
public void paintCompenent (Graphics g) {

the compiler wopuld have spat this out
"method does not override or implement a method from a supertype"