这是我的代码，我收到以下错误可以有人帮忙吗？它很好，但我不知道突然发生了什么......
基本上有两个文本框第一个是从提到的列表获取值，另一个是从数据库获取值第一个工作正常... 问题是当我尝试在第二个txtfield写任何东西时给出了这个错误
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import javax.swing.AbstractAction;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JWindow;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
import javax.swing.border.LineBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class Test {
static final String URL = "jdbc:mysql://localhost:3306/timetable?useSSL=false";
// Database credentials
public Test() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextField tftea = new JTextField(20);
JTextField f = new JTextField(20);
AutoSuggestor semtea = new AutoSuggestor(tftea, frame, null, Color.WHITE.brighter(), Color.BLUE, Color.RED,
0.75f) {
@Override
boolean wordTyped(String typedWord) {
ArrayList<String> words = new ArrayList<>();
try {
Connection conn = DriverManager.getConnection(URL, USER, PASS);
PreparedStatement ps = conn.prepareStatement("SELECT DISTINCT program FROM `sem`");
ResultSet result = ps.executeQuery();
while (result.next()) {
// comboBoxName.addItem(result.getString("teacher"));
String a = result.getString("program");
words.add(a);
System.out.println(a);
}
} catch (Exception ex) {
ex.printStackTrace();
}
setDictionary(words);
return super.wordTyped(typedWord);// now call super to check for
// any matches against
// newest dictionary
}
};
AutoSuggestor autoSuggestor = new AutoSuggestor(f, frame, null, Color.WHITE.brighter(), Color.BLUE, Color.RED, 0.75f) {
@Override
boolean wordTyped(String typedWord) {
//create list for dictionary this in your case might be done via calling a method which queries db and returns results as arraylist
ArrayList<String> words = new ArrayList<>();
words.add("hello");
words.add("heritage");
words.add("happiness");
words.add("goodbye");
words.add("cruel");
words.add("car");
words.add("war");
words.add("will");
words.add("world");
words.add("wall");
setDictionary(words);
//addToDictionary("bye");//adds a single word
return super.wordTyped(typedWord);//now call super to check for any matches against newest dictionary
}
};
JPanel p = new JPanel();
p.add(f);
p.add(tftea);
frame.add(p);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Test();
}
});
}
}
class AutoSuggestor {
private final JTextField textField;
private final Window container;
private JPanel suggestionsPanel;
private JWindow autoSuggestionPopUpWindow;
private String typedWord;
private final ArrayList<String> dictionary = new ArrayList<>();
private int currentIndexOfSpace, tW, tH;
private DocumentListener documentListener = new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
@Override
public void removeUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
@Override
public void changedUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
};
private final Color suggestionsTextColor;
private final Color suggestionFocusedColor;
public AutoSuggestor(JTextField textField, Window mainWindow, ArrayList<String> words, Color popUpBackground, Color textColor, Color suggestionFocusedColor, float opacity) {
this.textField = textField;
this.suggestionsTextColor = textColor;
this.container = mainWindow;
this.suggestionFocusedColor = suggestionFocusedColor;
this.textField.getDocument().addDocumentListener(documentListener);
setDictionary(words);
typedWord = "";
currentIndexOfSpace = 0;
tW = 0;
tH = 0;
autoSuggestionPopUpWindow = new JWindow(mainWindow);
autoSuggestionPopUpWindow.setOpacity(opacity);
suggestionsPanel = new JPanel();
suggestionsPanel.setLayout(new GridLayout(0, 1));
suggestionsPanel.setBackground(popUpBackground);
addKeyBindingToRequestFocusInPopUpWindow();
}
private void addKeyBindingToRequestFocusInPopUpWindow() {
textField.getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "Down released");
textField.getActionMap().put("Down released", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent ae) {//focuses the first label on popwindow
for (int i = 0; i < suggestionsPanel.getComponentCount(); i++) {
if (suggestionsPanel.getComponent(i) instanceof SuggestionLabel) {
((SuggestionLabel) suggestionsPanel.getComponent(i)).setFocused(true);
autoSuggestionPopUpWindow.toFront();
autoSuggestionPopUpWindow.requestFocusInWindow();
suggestionsPanel.requestFocusInWindow();
suggestionsPanel.getComponent(i).requestFocusInWindow();
break;
}
}
}
});
suggestionsPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "Down released");
suggestionsPanel.getActionMap().put("Down released", new AbstractAction() {
int lastFocusableIndex = 0;
@Override
public void actionPerformed(ActionEvent ae) {//allows scrolling of labels in pop window (I know very hacky for now :))
ArrayList<SuggestionLabel> sls = getAddedSuggestionLabels();
int max = sls.size();
if (max > 1) {//more than 1 suggestion
for (int i = 0; i < max; i++) {
SuggestionLabel sl = sls.get(i);
if (sl.isFocused()) {
if (lastFocusableIndex == max - 1) {
lastFocusableIndex = 0;
sl.setFocused(false);
autoSuggestionPopUpWindow.setVisible(false);
setFocusToTextField();
checkForAndShowSuggestions();//fire method as if document listener change occured and fired it
} else {
sl.setFocused(false);
lastFocusableIndex = i;
}
} else if (lastFocusableIndex <= i) {
if (i < max) {
sl.setFocused(true);
autoSuggestionPopUpWindow.toFront();
autoSuggestionPopUpWindow.requestFocusInWindow();
suggestionsPanel.requestFocusInWindow();
suggestionsPanel.getComponent(i).requestFocusInWindow();
lastFocusableIndex = i;
break;
}
}
}
} else {//only a single suggestion was given
autoSuggestionPopUpWindow.setVisible(false);
setFocusToTextField();
checkForAndShowSuggestions();//fire method as if document listener change occured and fired it
}
}
});
}
private void setFocusToTextField() {
container.toFront();
container.requestFocusInWindow();
textField.requestFocusInWindow();
}
public ArrayList<SuggestionLabel> getAddedSuggestionLabels() {
ArrayList<SuggestionLabel> sls = new ArrayList<>();
for (int i = 0; i < suggestionsPanel.getComponentCount(); i++) {
if (suggestionsPanel.getComponent(i) instanceof SuggestionLabel) {
SuggestionLabel sl = (SuggestionLabel) suggestionsPanel.getComponent(i);
sls.add(sl);
}
}
return sls;
}
private void checkForAndShowSuggestions() {
typedWord = getCurrentlyTypedWord();
suggestionsPanel.removeAll();//remove previos words/jlabels that were added
//used to calcualte size of JWindow as new Jlabels are added
tW = 0;
tH = 0;
boolean added = wordTyped(typedWord);
if (!added) {
if (autoSuggestionPopUpWindow.isVisible()) {
autoSuggestionPopUpWindow.setVisible(false);
}
} else {
showPopUpWindow();
setFocusToTextField();
}
}
protected void addWordToSuggestions(String word) {
SuggestionLabel suggestionLabel = new SuggestionLabel(word, suggestionFocusedColor, suggestionsTextColor, this);
calculatePopUpWindowSize(suggestionLabel);
suggestionsPanel.add(suggestionLabel);
}
public String getCurrentlyTypedWord() {//get newest word after last white spaceif any or the first word if no white spaces
String text = textField.getText();
String wordBeingTyped = "";
if (text.contains(" ")) {
int tmp = text.lastIndexOf(" ");
if (tmp >= currentIndexOfSpace) {
currentIndexOfSpace = tmp;
wordBeingTyped = text.substring(text.lastIndexOf(" "));
}
} else {
wordBeingTyped = text;
}
return wordBeingTyped.trim();
}
private void calculatePopUpWindowSize(JLabel label) {
//so we can size the JWindow correctly
if (tW < label.getPreferredSize().width) {
tW = label.getPreferredSize().width;
}
tH += label.getPreferredSize().height;
}
private void showPopUpWindow() {
autoSuggestionPopUpWindow.getContentPane().add(suggestionsPanel);
autoSuggestionPopUpWindow.setMinimumSize(new Dimension(textField.getWidth(), 30));
autoSuggestionPopUpWindow.setSize(tW, tH);
autoSuggestionPopUpWindow.setVisible(true);
int windowX = 0;
int windowY = 0;
windowX = container.getX() + textField.getX() + 5;
if (suggestionsPanel.getHeight() > autoSuggestionPopUpWindow.getMinimumSize().height) {
windowY = container.getY() + textField.getY() + textField.getHeight() + autoSuggestionPopUpWindow.getMinimumSize().height;
} else {
windowY = container.getY() + textField.getY() + textField.getHeight() + autoSuggestionPopUpWindow.getHeight();
}
autoSuggestionPopUpWindow.setLocation(windowX, windowY);
autoSuggestionPopUpWindow.setMinimumSize(new Dimension(textField.getWidth(), 30));
autoSuggestionPopUpWindow.revalidate();
autoSuggestionPopUpWindow.repaint();
}
public void setDictionary(ArrayList<String> words) {
dictionary.clear();
if (words == null) {
return;//so we can call constructor with null value for dictionary without exception thrown
}
for (String word : words) {
dictionary.add(word);
}
}
public JWindow getAutoSuggestionPopUpWindow() {
return autoSuggestionPopUpWindow;
}
public Window getContainer() {
return container;
}
public JTextField getTextField() {
return textField;
}
public void addToDictionary(String word) {
dictionary.add(word);
}
boolean wordTyped(String typedWord) {
if (typedWord.isEmpty()) {
return false;
}
//System.out.println("Typed word: " + typedWord);
boolean suggestionAdded = false;
for (String word : dictionary) {//get words in the dictionary which we added
boolean fullymatches = true;
for (int i = 0; i < typedWord.length(); i++) {//each string in the word
if (!typedWord.toLowerCase().startsWith(String.valueOf(word.toLowerCase().charAt(i)), i)) {//check for match
fullymatches = false;
break;
}
}
if (fullymatches) {
addWordToSuggestions(word);
suggestionAdded = true;
}
}
return suggestionAdded;
}
}
class SuggestionLabel extends JLabel {
private boolean focused = false;
private final JWindow autoSuggestionsPopUpWindow;
private final JTextField textField;
private final AutoSuggestor autoSuggestor;
private Color suggestionsTextColor, suggestionBorderColor;
public SuggestionLabel(String string, final Color borderColor, Color suggestionsTextColor, AutoSuggestor autoSuggestor) {
super(string);
this.suggestionsTextColor = suggestionsTextColor;
this.autoSuggestor = autoSuggestor;
this.textField = autoSuggestor.getTextField();
this.suggestionBorderColor = borderColor;
this.autoSuggestionsPopUpWindow = autoSuggestor.getAutoSuggestionPopUpWindow();
initComponent();
}
private void initComponent() {
setFocusable(true);
setForeground(suggestionsTextColor);
addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent me) {
super.mouseClicked(me);
replaceWithSuggestedText();
autoSuggestionsPopUpWindow.setVisible(false);
}
});
getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, true), "Enter released");
getActionMap().put("Enter released", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent ae) {
replaceWithSuggestedText();
autoSuggestionsPopUpWindow.setVisible(false);
}
});
}
public void setFocused(boolean focused) {
if (focused) {
setBorder(new LineBorder(suggestionBorderColor));
} else {
setBorder(null);
}
repaint();
this.focused = focused;
}
public boolean isFocused() {
return focused;
}
private void replaceWithSuggestedText() {
String suggestedWord = getText();
String text = textField.getText();
String typedWord = autoSuggestor.getCurrentlyTypedWord();
String t = text.substring(0, text.lastIndexOf(typedWord));
String tmp = t + text.substring(text.lastIndexOf(typedWord)).replace(typedWord, suggestedWord);
textField.setText(tmp + " ");
}
}
错误
Exception in thread "AWT-EventQueue-0" java.lang.StringIndexOutOfBoundsException: String index out of range: 0
at java.lang.String.charAt(Unknown Source)
at timetable.AutoSuggestor.wordTyped(Test.java:360)
at timetable.Test$1.wordTyped(Test.java:64)
at timetable.AutoSuggestor.checkForAndShowSuggestions(Test.java:256)
at timetable.AutoSuggestor.access$0(Test.java:247)
at timetable.AutoSuggestor$1.insertUpdate(Test.java:127)
at javax.swing.text.AbstractDocument.fireInsertUpdate(Unknown Source)
at javax.swing.text.AbstractDocument.handleInsertString(Unknown Source)
at javax.swing.text.AbstractDocument.insertString(Unknown Source)
at javax.swing.text.PlainDocument.insertString(Unknown Source)
at javax.swing.text.AbstractDocument.replace(Unknown Source)
at javax.swing.text.JTextComponent.replaceSelection(Unknown Source)
at javax.swing.text.DefaultEditorKit$DefaultKeyTypedAction.actionPerformed(Unknown Source)
at javax.swing.SwingUtilities.notifyAction(Unknown Source)
at javax.swing.JComponent.processKeyBinding(Unknown Source)
at javax.swing.JComponent.processKeyBindings(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
这是创建问题的代码
public void addToDictionary(String word) {
dictionary.add(word);
}
boolean wordTyped(String typedWord) {
if (typedWord.isEmpty()) {
return false;
}
//System.out.println("Typed word: " + typedWord);
boolean suggestionAdded = false;
for (String word : dictionary) {//get words in the dictionary which we added
boolean fullymatches = true;
for (int ii = 0; ii < typedWord.length(); ii++) {//each string in the word
if (!typedWord.toLowerCase().startsWith(String.valueOf(word.toLowerCase().charAt(ii)), ii)) {//check for match
fullymatches = false;
break;
}
}
if (fullymatches) {
addWordToSuggestions(word);
suggestionAdded = true;
}
}
return suggestionAdded;
}
}
答案 0 :(得分：0)
代码破解是：
if (!typedWord.toLowerCase().startsWith(String.valueOf(word.toLowerCase().charAt(ii)), ii))
所以，如果
typedWord = "household"
word = "house"
然后对于ii = 5，代码将尝试读取typedWord和word的第6个字符，导致异常，因为“house”只有5个字符。
也许你的数据库中有一个空字。