我需要在用户输入JTextArea时显示建议（自动填充），有点像手机T9。
我不知道如何在myTextAreaKeyTyped()事件中执行此操作。
这个应用程序是一个打字助手。它显示键盘上不存在的字符变体。
例如。按'A'，显示Â：1，Á：2，À：3 ...如果按1,2或3，'A'将被替换。
它已经完成，但变体显示在JLabel底部的JFrame中，因为我不知道如何执行此操作。
答案 0 :(得分：13)
这是一个让自己受到启发的片段。您可能需要重新组织一些代码以使其更易于维护，但它应该为您提供要点。
基本上，我们会监听关键事件（我发现它与侦听文档事件无关，例如，如果用户粘贴了一些文本，我不希望出现建议面板），以及插入符号时至少2个字符后面，我们提出一些建议，使用包含建议JList的弹出菜单（这里的建议实际上没有意义，但将它绑定到一个字典并不太难）。至于你提到的捷径，这不应该太难。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTextArea;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.BadLocationException;
public class Test {
public class SuggestionPanel {
private JList list;
private JPopupMenu popupMenu;
private String subWord;
private final int insertionPosition;
public SuggestionPanel(JTextArea textarea, int position, String subWord, Point location) {
this.insertionPosition = position;
this.subWord = subWord;
popupMenu = new JPopupMenu();
popupMenu.removeAll();
popupMenu.setOpaque(false);
popupMenu.setBorder(null);
popupMenu.add(list = createSuggestionList(position, subWord), BorderLayout.CENTER);
popupMenu.show(textarea, location.x, textarea.getBaseline(0, 0) + location.y);
}
public void hide() {
popupMenu.setVisible(false);
if (suggestion == this) {
suggestion = null;
}
}
private JList createSuggestionList(final int position, final String subWord) {
Object[] data = new Object[10];
for (int i = 0; i < data.length; i++) {
data[i] = subWord + i;
}
JList list = new JList(data);
list.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setSelectedIndex(0);
list.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
insertSelection();
}
}
});
return list;
}
public boolean insertSelection() {
if (list.getSelectedValue() != null) {
try {
final String selectedSuggestion = ((String) list.getSelectedValue()).substring(subWord.length());
textarea.getDocument().insertString(insertionPosition, selectedSuggestion, null);
return true;
} catch (BadLocationException e1) {
e1.printStackTrace();
}
hideSuggestion();
}
return false;
}
public void moveUp() {
int index = Math.min(list.getSelectedIndex() - 1, 0);
selectIndex(index);
}
public void moveDown() {
int index = Math.min(list.getSelectedIndex() + 1, list.getModel().getSize() - 1);
selectIndex(index);
}
private void selectIndex(int index) {
final int position = textarea.getCaretPosition();
list.setSelectedIndex(index);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
textarea.setCaretPosition(position);
};
});
}
}
private SuggestionPanel suggestion;
private JTextArea textarea;
protected void showSuggestionLater() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
showSuggestion();
}
});
}
protected void showSuggestion() {
hideSuggestion();
final int position = textarea.getCaretPosition();
Point location;
try {
location = textarea.modelToView(position).getLocation();
} catch (BadLocationException e2) {
e2.printStackTrace();
return;
}
String text = textarea.getText();
int start = Math.max(0, position - 1);
while (start > 0) {
if (!Character.isWhitespace(text.charAt(start))) {
start--;
} else {
start++;
break;
}
}
if (start > position) {
return;
}
final String subWord = text.substring(start, position);
if (subWord.length() < 2) {
return;
}
suggestion = new SuggestionPanel(textarea, position, subWord, location);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
textarea.requestFocusInWindow();
}
});
}
private void hideSuggestion() {
if (suggestion != null) {
suggestion.hide();
}
}
protected void initUI() {
final JFrame frame = new JFrame();
frame.setTitle("Test frame on two screens");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new BorderLayout());
textarea = new JTextArea(24, 80);
textarea.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
textarea.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == KeyEvent.VK_ENTER) {
if (suggestion != null) {
if (suggestion.insertSelection()) {
e.consume();
final int position = textarea.getCaretPosition();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
textarea.getDocument().remove(position - 1, 1);
} catch (BadLocationException e) {
e.printStackTrace();
}
}
});
}
}
}
}
@Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_DOWN && suggestion != null) {
suggestion.moveDown();
} else if (e.getKeyCode() == KeyEvent.VK_UP && suggestion != null) {
suggestion.moveUp();
} else if (Character.isLetterOrDigit(e.getKeyChar())) {
showSuggestionLater();
} else if (Character.isWhitespace(e.getKeyChar())) {
hideSuggestion();
}
}
@Override
public void keyPressed(KeyEvent e) {
}
});
panel.add(textarea, BorderLayout.CENTER);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Test().initUI();
}
});
}
}