javax.swing.Box help

[Eric Larsen]

Hi guys, I've got an app (an excercise from Chapter 13 of Head First Java) to make a drum/percussion instruments machine and I need a little help with the GUI. The JLabels on the left are in a Box component , and I need some way to get them to match up with each row of JCheckBoxes in the center (in another Box.) Thanks in advance for the help!

package com.teslarobotics.music;

import java.awt.*;
import javax.swing.*;
import javax.sound.midi.*;
import java.util.*;
import java.awt.event.*;
import com.teslarobotics.utilities.*;

public class BeatBox {

	JPanel mainPanel;
	ArrayList<JCheckBox> checkBoxList;
	Sequencer sequencer;
	Sequence sequence;
	Track track;
	JFrame frame;
	String[] instrumentNames = {"Bass Drum","Closed Hi-Hat","Open Hi-Hat","Acoustic Snare","Crash Symbal","Hand Clap","High Tom","Hi Bongo","Maracas","Whistle","Low Conga","Cowbell","Vibraslap","Low-mid Tom","High Agogo","Open Hi Conga"};
	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();

	}

	public void buildGui () {

		frame = new JFrame("Rainstick - The Rythm Machine");
		frame.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 StartListener());
		buttonBox.add(start);

		JButton stop = new JButton("Stop");
		stop.addActionListener(new StopListener());
		buttonBox.add(stop);

		JButton upTempo = new JButton("Tempo Up");
		upTempo.addActionListener(new UpTempoListener());
		buttonBox.add(upTempo);

		JButton downTempo = new JButton("Tempo Down");
		downTempo.addActionListener(new DownTempoListener());
		buttonBox.add(downTempo);

		Box nameBox = new Box(BoxLayout.Y_AXIS);
		for (int i = 0; i < 16; i++) {
			nameBox.add(new JLabel(instrumentNames[i]));
		}

		background.add(BorderLayout.EAST, buttonBox);
		background.add(BorderLayout.WEST, nameBox);

		frame.getContentPane().add(background);

		GridLayout grid = new GridLayout(16, 16);
		grid.setVgap(1);
		grid.setHgap(2);
		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);
		}

		setUpMidi();

		frame.setBounds(50, 50, 300, 300);
		frame.pack();
		frame.setVisible(true);

	}

	public void setUpMidi() {

		try {

			sequencer = MidiSystem.getSequencer();
			sequencer.open();
			sequence = new Sequence(Sequence.PPQ, 4);
			track = sequence.createTrack();
			sequencer.setTempoInBPM(120);

		} catch (Exception e) {

			System.out.println("Error in method setUpMidi");
			e.printStackTrace();

		}

	}

	public void buildTrackAndStart () {

		int[] trackList = null;

		sequence.deleteTrack(track);
		track = sequence.createTrack();

		for (int i = 0; i < 16; i++) {

			trackList = new int[16];

			int key = instruments[i];

			for (int j = 0; j < 16; j++) {

				JCheckBox jc = (JCheckBox) checkBoxList.get(j + (16 * i));
				if (jc.isSelected()) {
					trackList[j] = key;
				} else {
					trackList[j] = 0;
				}

			}

			makeTracks(trackList);
			track.add(MidiUtilities.makeMidiEvent(176, 1, 127, 0, 16));

		}

		track.add(MidiUtilities.makeMidiEvent(192, 9, 1, 0, 16));

		try {

			sequencer.setSequence(sequence);
			sequencer.setLoopCount(Sequencer.LOOP_CONTINUOUSLY);
			sequencer.start();
			sequencer.setTempoInBPM(120);

		} catch (Exception e) {

			System.out.println("Error in method buildTrackAndStart.");
			e.printStackTrace();

		}

	}

	public class StartListener implements ActionListener {

		public void actionPerformed (ActionEvent a) {

			buildTrackAndStart();

		}

	}

	public class StopListener implements ActionListener {

		public void actionPerformed (ActionEvent b) {

			sequencer.stop();

		}

	}

	public class UpTempoListener implements ActionListener {

		public void actionPerformed (ActionEvent c) {

			float tempoFactor = sequencer.getTempoFactor();
			sequencer.setTempoFactor((float) (tempoFactor * 1.03));

		}

	}

	public class DownTempoListener implements ActionListener {

		public void actionPerformed (ActionEvent d) {

			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(MidiUtilities.makeMidiEvent(144, 9, key, 100, i));
				track.add(MidiUtilities.makeMidiEvent(128, 9, key, 100, i + 1));
			}
		}

	}

}

[Michael Dunn]

a simple alternative

//Box nameBox = new Box(BoxLayout.Y_AXIS);
JPanel nameBox = new JPanel(new GridLayout(0,1,0,2));