HFJ BeatBox program, problems

[Davy Kelly]

Hey everyone,

I am going though the Head First Java 2nd ed nicely.

I made up the BeatBox program on chapter 13 page 420, and it worked nicely.

I was finished chapter 14 and tried to add in the inner classes to make the program save the beat.

and add in more buttons for this to happen.

I done all that, and it came up with many errors, so many in fact that it said the original program was wrong.

so I undid all the changes, and tried to compile, now I went through the program with a fine tooth comb, it is perfectly the same as the book, so it should work again, but it will not compile.

I have noticed that there was a program on page 437 called Box, whixh I made up, as I like to see things work, so I understand them.

I have since got rid of this class Box, cause I think this was making the main BeatBox program not work.

However, I still get lots of errors, and I am not sure why as it worked before with the exact same code.

here is my beatbox code:

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 Symbol", 
"Hand Clap", "High Tom", "Hi Bongo", "Maracas", "Whistle", "Low Conga",
"Cowbell", "Vibraslap", "Low-mid Tom", "High Agogo", "Open Hi Conga"};
//these are the real drum beats
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();
}//end main method
 
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]));
}//end for loop
 
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);
 
//make the checkboxes and set them to false so that none are checked
for (int i = 0; i < 256; i++)
{
JCheckBox c = new JCheckBox();
c.setSelected(false);
checkboxList.add(c);
mainPanel.add(c);
}//end for loop
 
setUpMidi();
 
theFrame.setBounds(50, 50, 300, 300);
theFrame.pack();
theFrame.setVisible(true);
}//end buildGUI method

public void setUpMidi()
{
//the usual midi setup stuff for getting the sequencer, the sequence and the track
try
{
sequencer = MidiSystem.getSequencer();
sequencer.open();
sequence = new Sequence(Sequence.PPQ, 4);
track = sequence.createTrack();
sequencer.setTempoInBPM(120);
}
catch (Exception e)
{
e.printStackTrace();
}//end try catch
}//close setUpMidi method
 
//this is where it all happens, we turn checkbox state into MIDI events, and add them to the track
public void buildTrackAndStart()
{
//16 element array to hold the values for one instrument accross 16 beats
int[] trackList = null;
 
sequence.deleteTrack(track);//get rid of old track to make a fresh one
track = sequence.createTrack();
 
//do this for eack of the 16 rows of instruments   outer for loop
for (int i = 0; i < 16; i++)
{
trackList = new int[16];
 
int key = instruments[i];//sets the key that represents which instrument this is
 
//inner for loop for each of the beats for this row
for (int j = 0; j < 16; j++)
{
JCheckBox jc = (JCheckBox) checkboxList.get(j + (16 * i));
/*is the checkbox at this beat selected?
 if yes put the key value in the slot in the array, the slot that represents the beat
*/
if (jc.isSelected())
{
trackList[j] = key;
}
else
{
trackList[j] = 0;
}
}//end inner for loop
 
makeTracks(trackList);
//for this instrument and for all 16 beats, make events and add them to the track
track.add(makeEvent(176, 1, 127, 0, 16));
}//end outer for loop
 
//we always want to make sure there is an event at beat 16 (0-15) 
otherwise the beatbox might not go the full 16 beats 
before it satrts at zero
track.add(makeEvent(192, 9, 1, 0, 15));

//lets you specify the number of loop iterations or in this case, continuos playing
try
{
sequencer.setSequence(sequence);
sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);
//play the thing now
sequencer.start();
sequencer.setTempoInBPM(120);
}
catch (Exception e)
{
e.printStackTrace();
} //end try catch
}//end buildTrackAndStart method
 
//inner class 1
public class MyStartListener implements ActionListener
{
public void actionPerformed(ActionEvent a)
{
buildTrackAndStart();
}//close actionPerformed method
}//close inner MyStartListener class
 
//inner class 2
public class MyStopListener implements ActionListener
{
public void actionPerformed(ActionEvent a)
{
sequencer.stop();
}//close actionPerformed method
}//close inner MyStopListener class
 
//inner class 3
//the tempo factor scales the sequencer's tempo by the factor provided. the default is 1.0 so we are adjusting +/- 3% per click
public class MyUpTempoListener implements ActionListener
{
public void actionPerformed(ActionEvent a)
{
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * 1.03));
}//close actionPerformed method
}//close inner MyUpTempoListener class
 
//inner class 4
//the tempo factor scales the sequencer's tempo by the factor provided. the default is 1.0 so we are adjusting +/- 3% per click
public class MyDownTempoListener implements ActionListener
{
public void actionPerformed(ActionEvent a)
{
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * .97));
}//close actionPerformed method
}//close inner MyUpTempoListener class
 


 
/*this makes events for one instrument at a time, for all 16 beats.
  so it might get an int[] for the bass drumn, and each index in the array will hold either the key of that instrument or a zero.
  the instrument isnt supposed to play at that beat
  otherwise, make an event and add it to the track
*/
public void makeTracks(int[] list)
{
for (int i = 0; i < 16; i++)
{
int key = list[i];
if (key != 0)
{
//make the NOTE ON and NOTE OFF events, add them to track
track.add(makeEvent(144, 9, key, 100, i));
track.add(makeEvent(128, 9, key, 100, i+1));
}
}//close for loop
}//close makeTracks method
 
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; //need to return as the method is not void
}//close makeEvent method
}//close BeatBox class

here is a screen shot of my errors which I never got the last time.

can someone help?

Davy

[ November 23, 2006: Message edited by: Davy Kelly ]
[ November 23, 2006: Message edited by: Davy Kelly ]

[Keith Lynn]

According to your output the problem is in the class Box. If you look at the individual errors, they will tell you what is expected.

[Davy Kelly]

Keith,

What I was asking is why did it compile fine and run fine in the first place?
ok I made a few changes, but I have set the code back to its original working order, so it should work fine now, but its not

davy

[Davy Kelly]

I have downloaded the code from O'reilly the Code Kitchen jar file.

I extracted the files and saved the BeatBoxSaveOnly.java file in where all my other java files save and get compiles from.

I compiled this file, and this returned 11 errors.

again saying there is a problem with the Box class, which I see is a class within the java language.

I am at a loss, I have spent all day trying to figure this out, but to no avail.

I cannot add buttons to the buttonBox, as the main problem is with the class Box.

Can someone help please, instead of telling me the compilation errors tell me what the problem is?

davy
[ November 24, 2006: Message edited by: Davy Kelly ]