不管您当前的问题是什么,您都不应该在 JTextField 中使用 KeyListener。请改用 DocumentListener 或 DocumentFilter。鉴于您的代码,我猜想 DocumentFilter 是您所需要的,因为您希望在输入 JTextField 时和显示之前更改它的文本。
例如,
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.PlainDocument;
public class SwapAForAleph {
// No idea of the correct unicode for this!!!
public static final char SINDHI_ALIF = '\u0623';
public static void main(String[] args) {
final JTextField textField = new JTextField(10);
textField.setFont(textField.getFont().deriveFont(32f));
PlainDocument doc = (PlainDocument) textField.getDocument();
doc.setDocumentFilter(new DocumentFilter() {
@Override
public void insertString(FilterBypass fb, int offset, String text,
AttributeSet attr) throws BadLocationException {
text = filterText(text);
super.insertString(fb, offset, text, attr);
}
@Override
public void replace(FilterBypass fb, int offset, int length,
String text, AttributeSet attrs) throws BadLocationException {
text = filterText(text);
super.replace(fb, offset, length, text, attrs);
}
private String filterText(String text) {
return text.replace('a', SINDHI_ALIF);
}
});
JPanel panel = new JPanel();
panel.add(textField);
JOptionPane.showMessageDialog(null, panel);
}
}
或者换个角度看...
import java.awt.ComponentOrientation;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.PlainDocument;
public class NonEnglishTextField {
public static final char ALEPH = '\u05D0';
public static void main(String[] args) {
final JTextField textField = new JTextField(20);
textField.setFont(textField.getFont().deriveFont(32f));
textField.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
textField.setHorizontalAlignment(SwingConstants.RIGHT);
PlainDocument doc = (PlainDocument) textField.getDocument();
doc.setDocumentFilter(new DocumentFilter() {
@Override
public void insertString(FilterBypass fb, int offset, String text,
AttributeSet attr) throws BadLocationException {
text = filterText(text);
super.insertString(fb, offset, text, attr);
}
@Override
public void replace(FilterBypass fb, int offset, int length,
String text, AttributeSet attrs) throws BadLocationException {
text = filterText(text);
super.replace(fb, offset, length, text, attrs);
}
private String filterText(String text) {
StringBuilder sb = new StringBuilder();
for (char c : text.toLowerCase().toCharArray()) {
if (c >= 'a' && c <= 'z') {
char newChar = (char) (c - 'a' + ALEPH);
sb.append(newChar);
} else {
sb.append(c);
}
}
return sb.toString();
}
});
JPanel panel = new JPanel();
panel.add(textField);
JOptionPane.showMessageDialog(null, panel);
}
}