What the program should do:
After the user clicks the “delete” button with a word selected from the list on the word manager gui window, another item (any item) from the word list should be selected (highlighted on the gui) so that the user doesn’t have to click back and forth to delete a series of words from the list.
I refer you to the following code snippet to illustrate the problem further:
logic.words.remove(w);
logic.save_words_to_disk();
populate_list();
word_list.setSelectedIndex(0); //doesn't make the selection in the list
The above code snippet can be used to run a “find” search in the browser to locate the section of code I am referring too. Also, to illustrate what I mean, the list should be populated with a few items beforehand (an empty list obviously won’t do when testing this).
What happens:
The selected word is deleted, but, apparently, the method call word_list.setSelectedIndex(…) has no effect, as nothing is selected after it is called. The method getSelectedIndex() also doesn’t work, but I’ve used a work around (list selection listener) to get the currently selected index in the list, but its ugly (not elegant).
My question:
What am I doing wrong? I’ve tried the set list selection method in a simple program and it works fine, but for some reason, it doesn’t work in my main project. I’ve posted the full source code for both my main project and the simple test project below.
Any help would be appreciated. Thanks!
—MAIN PROJECT—
package spellingbee;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.io.*;
import java.util.ArrayList;
import java.util.Random;
import javax.sound.sampled.*;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class SpellingBee {
public static void main(String[] args) {
//create objects
GUI gui = new GUI();
Logic logic = new Logic();
//link objects
gui.logic = logic;
logic.gui = gui;
AudioRecorder.logic = logic;
//start program
AudioRecorder.init();
gui.initialize();
logic.load_words_from_disk();
logic.choose_word();
logic.prompt_word();
}
}
class GUI {
//this link is set externally
public Logic logic = null;
public WordManager word_manager = null;
public MainGUI main_gui = null;
public void initialize() {
main_gui = new MainGUI();
word_manager = new WordManager();
}
public void show_word_manager() {
word_manager.populate_list();
word_manager.window.setLocationRelativeTo(main_gui.window);
word_manager.window.setVisible(true);
}
class MainGUI {
public JLabel input_label = null;
public JLabel last_word_label = null;
JFrame window = null;
public MainGUI() {
window = new JFrame("Spelling Bee");
window.addKeyListener(new Keyboard());
window.setLayout(new BorderLayout());
input_label = new JLabel("", JLabel.CENTER);
input_label.setFont(new Font("", Font.PLAIN, 32));
input_label.setFocusable(false);
input_label.setPreferredSize(new Dimension(400, 100));
last_word_label = new JLabel("", JLabel.CENTER);
last_word_label.setFont(new Font("", Font.ITALIC, 16));
last_word_label.setFocusable(false);
last_word_label.setPreferredSize(new Dimension(400, 30));
JLabel help_label_1 = new JLabel("Press '0' to hear the current word.", JLabel.CENTER);
JLabel help_label_2 = new JLabel("Press '1' to manage word list.", JLabel.CENTER);
JPanel help_panel = new JPanel(new GridLayout(2, 1));
help_panel.add(help_label_1);
help_panel.add(help_label_2);
window.getContentPane().add(input_label, BorderLayout.CENTER);
window.getContentPane().add(last_word_label, BorderLayout.NORTH);
window.getContentPane().add(help_panel, BorderLayout.SOUTH);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.pack();
window.setLocationRelativeTo(null);
window.setVisible(true);
}
}
class WordManager {
public JDialog window = null;
public JList word_list = null;
public DefaultListModel list_model = null;
public JButton delete_button = null;
public JButton record_button = null;
public int list_selection;
public JTextField input_field = null;
public WordManager() {
window = new JDialog(main_gui.window, "Word Viewer", true);
//window.setPreferredSize(new Dimension(300, 300));
list_model = new DefaultListModel();
DefaultListSelectionModel dlsm = new DefaultListSelectionModel();
dlsm.clearSelection();
word_list = new JList(list_model);
word_list.setSelectionModel(dlsm);
word_list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
word_list.addListSelectionListener(new SelectionManager());
JScrollPane word_list_scroll_pane = new JScrollPane(word_list);
word_list_scroll_pane.setPreferredSize(new Dimension(150, 300));
ButtonManager button_manager = new ButtonManager();
delete_button = new JButton("Delete");
delete_button.setActionCommand("delete_button");
delete_button.addActionListener(button_manager);
//delete_button.setPreferredSize(new Dimension(100,30));
record_button = new JButton("Record");
record_button.setActionCommand("start_record");
record_button.addActionListener(button_manager);
input_field = new JTextField(15);
JPanel record_panel = new JPanel(new GridLayout(2, 1));
record_panel.add(input_field);
record_panel.add(record_button);
JPanel east_panel = new JPanel(new BorderLayout());
east_panel.add(delete_button, BorderLayout.SOUTH);
east_panel.add(record_panel, BorderLayout.NORTH);
window.setLayout(new BorderLayout());
window.add(word_list_scroll_pane, BorderLayout.WEST);
window.add(east_panel, BorderLayout.EAST);
window.setDefaultCloseOperation(JDialog.HIDE_ON_CLOSE);
window.pack();
window.setLocationRelativeTo(main_gui.window);
}
public void populate_list() {
//this code creates a thread on the event dispatch thread
//which is needed for gui actions. not doing this for gui
//operations can cause unpredictable errors that are
//difficult to reproduce
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
populate_list_helper();
}
});
}
private void populate_list_helper() {
//this line will determine whether or not a block of code is running
//on the event dispatching thread
//System.out.println(javax.swing.SwingUtilities.isEventDispatchThread());
list_model.clear();
for (Word w : logic.words) {
list_model.addElement(w.spelling);
}
}
class SelectionManager implements ListSelectionListener {
@Override
public void valueChanged(ListSelectionEvent e) {
list_selection = e.getFirstIndex();
}
}
class ButtonManager implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
String action_command = e.getActionCommand();
if (action_command.equals("delete_button")) {
int selection = list_selection;
if (selection != -1) {
String selected_string = word_list.getModel().getElementAt(selection).toString();
for (Word w : logic.words) {
if (w.spelling.equals(selected_string)) {
logic.words.remove(w);
logic.save_words_to_disk();
populate_list();
word_list.setSelectedIndex(0);
return;
}
}
}
} else if (action_command.equals("start_record")) {
if (!input_field.getText().isEmpty()) {
record_button.setActionCommand("stop_record");
record_button.setText("Stop Recording");
logic.start_recording();
} else {
SoundPlayer.play("wrong.wav");
}
} else if (action_command.equals("stop_record")) {
record_button.setActionCommand("start_record");
logic.stop_recording();
record_button.setText("Record");
input_field.grabFocus();
input_field.selectAll();
}
}
}
}
class Keyboard extends KeyAdapter {
@Override
public void keyTyped(KeyEvent e) {
logic.process_keyboard_input(e);
}
}
}
class Logic {
public GUI gui = null;
ArrayList<Word> words = new ArrayList<Word>();
Word current_word = null;
//public byte[] sound_data = null;
public void save_words_to_disk() {
try {
FileOutputStream fos = new FileOutputStream("src\\spellingbee\\words.dat");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(words);
oos.close();
} catch (Exception e) {
System.err.println("save_words_to_disk: " + e);
}
}
public void load_words_from_disk() {
try {
FileInputStream fis = new FileInputStream("src\\spellingbee\\words.dat");
ObjectInputStream ois = new ObjectInputStream(fis);
words = (ArrayList<Word>) ois.readObject();
ois.close();
} catch (Exception e) {
System.err.println("load_words_from_disk: " + e);
}
}
public void start_recording() {
AudioRecorder.captureAudio();
}
public void stop_recording() {
AudioRecorder.stopCapture = true;
}
public void process_new_word(byte[] sound_data) {
Word temp_word = new Word(gui.word_manager.input_field.getText(), sound_data);
words.add(temp_word);
temp_word.play();
if (words.size() == 1) {
choose_word();
}
gui.word_manager.populate_list();
save_words_to_disk();
}
public void choose_word() {
if (current_word != null) {
String old_word = current_word.spelling;
if (words.size() > 1) {
while (old_word.equals(current_word.spelling)) {
current_word = words.get(new Random().nextInt(words.size()));
}
} else {
current_word = words.get(0);
}
} else {
if (words.size() > 0) {
current_word = words.get(new Random().nextInt(words.size()));
}
}
}
public void prompt_word() {
if (current_word != null) {
current_word.play();
}
}
public void process_keyboard_input(KeyEvent e) {
char user_input = e.getKeyChar();
//verify input
if (!input_ok(user_input)) {
return;
}
switch (user_input) {
case '0':
prompt_word();
return;
case '1':
gui.show_word_manager();
return;
default:
break;
}
String result_string = gui.main_gui.input_label.getText();
gui.main_gui.input_label.setText(result_string + Character.toString(user_input));
result_string = gui.main_gui.input_label.getText();
String answer_string = current_word.spelling;
if (result_string.equalsIgnoreCase(answer_string)) {
SoundPlayer.play("ding.wav");
gui.main_gui.last_word_label.setText(gui.main_gui.input_label.getText().toLowerCase());
gui.main_gui.input_label.setText("");
choose_word();
prompt_word();
}
//check to see if input is correct so far
int result_length = result_string.length();
String partial_result = result_string.substring(0, result_length);
String partial_answer = answer_string.substring(0, result_length);
if (!partial_result.equalsIgnoreCase(partial_answer)) {
SoundPlayer.play("wrong.wav");
gui.main_gui.input_label.setText("");
}
}
public boolean input_ok(char input_value) {
boolean result = false;
switch (new Character(input_value).toString().toLowerCase().charAt(0)) {
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
case 'g':
case 'h':
case 'i':
case 'j':
case 'k':
case 'l':
case 'm':
case 'n':
case 'o':
case 'p':
case 'q':
case 'r':
case 's':
case 't':
case 'u':
case 'v':
case 'w':
case 'x':
case 'y':
case 'z':
case '0':
case '1':
result = true;
}
return result;
}
}
class Word implements Serializable {
public String spelling = null;
public byte[] audio_data = null;
public Word(String spelling, byte[] audio_data) {
this.spelling = spelling;
this.audio_data = audio_data;
System.out.println("");
}
public void play() {
SoundPlayer.play_data(audio_data);
}
}
class SoundPlayer {
static AudioFormat audio_format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, 44100.0F, 16, 2, 4, 44100.0F, false);
static public void play(String path) {
try {
Clip clip = AudioSystem.getClip();
InputStream audio_src = SpellingBee.class.getResourceAsStream(path);
InputStream buffered_in = new BufferedInputStream(audio_src);
AudioInputStream audioStream = AudioSystem.getAudioInputStream(buffered_in);
clip.open(audioStream);
clip.start();
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
static public void play_data(byte[] data) {
Clip clip = null;
try {
clip = AudioSystem.getClip();
} catch (Exception e) {
System.err.println("1 " + e.getMessage());
}
try {
clip.open(audio_format, data, 0, data.length);
} catch (LineUnavailableException e) {
System.err.println("2a " + e.getMessage());
} catch (IllegalArgumentException e) {
System.err.println("2b " + e.getMessage());
} catch (IllegalStateException e) {
System.err.println("2c " + e.getMessage());
} catch (SecurityException e) {
System.err.println("2d " + e.getMessage());
}
try {
clip.start();
} catch (Exception e) {
System.err.println("3 " + e.getMessage());
}
}
}
class AudioRecorder {
static boolean stopCapture = false;
static ByteArrayOutputStream byteArrayOutputStream;
static AudioFormat audioFormat = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, 44100.0F, 16, 2, 4, 44100.0F, false);
static TargetDataLine targetDataLine;
static private byte[] audioData = null;
public static Logic logic = null;
static public byte[] get_audio_data() {
return audioData;
}
static public void init() {
try {
DataLine.Info dataLineInfo = new DataLine.Info(TargetDataLine.class, audioFormat);
targetDataLine = (TargetDataLine) AudioSystem.getLine(dataLineInfo);
targetDataLine.open(audioFormat);
} catch (Exception e) {
System.err.println(e);
}
}
static public void captureAudio() {
try {
targetDataLine.start();
//Create a thread to capture the microphone data and start it
//running. It will run until the Stop button is clicked.
Thread captureThread = new Thread(new CaptureThread());
captureThread.start();
} catch (Exception e) {
System.out.println("4 " + e);
System.exit(0);
}//end catch
}//end captureAudio method
static class CaptureThread extends Thread {
//An arbitrary-size temporary holding buffer
byte tempBuffer[] = new byte[10000];
@Override
public void run() {
byteArrayOutputStream = new ByteArrayOutputStream();
stopCapture = false;
try {
//stopCapture will be set by another thread
while (!stopCapture) {
//Read data from the internal buffer of the data line.
int cnt = targetDataLine.read(tempBuffer, 0, tempBuffer.length);
if (cnt > 0) {
byteArrayOutputStream.write(tempBuffer, 0, cnt);
}
}
byteArrayOutputStream.close();
audioData = byteArrayOutputStream.toByteArray();
logic.process_new_word(audioData);
System.out.println();
} catch (Exception e) {
System.out.println("capture thread " + e);
System.exit(0);
}//end catch
}//end run
}//end inner class CaptureThread
}//end outer class AudioCapture01.java
—TEST PROJECT—
package testing;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
public class Testing {
public static void main(String[] args) {
JFrame frame = new JFrame();
String[] items = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k"};
final JList list = new JList(items);
list.setPreferredSize(new Dimension(200,200));
frame.setLayout(new BorderLayout());
JButton button = new JButton("select random item");
button.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e) {
list.setSelectedIndex(new Random().nextInt(11));
}
}
);
frame.getContentPane().add(list, BorderLayout.CENTER);
frame.getContentPane().add(button, BorderLayout.EAST);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
It is actually quite simple why your code does not work:
populate_list()where you callinvokeLaterwhich will invoke laterpopulate_list_helper()populate_list_helper()gets calledQuestion:
Why do you use invokeLater while you are already on the EDT (
ActionEventonly occurs on the EDT, that’s the whole point of EDT)? (Remember that EDT stands for Event Dispatching Thread)You have several options here:
populate_list_helper()instead of calling it ininvokeLaterpopulate_list_helper()restore the previous selection after repopulating your list.NB: Any reason for preventing multiple selection? This would be a lot friendlier to the end-user. He could delete several words in a single action.