永远不要使用Keylistener
(没有真正的理由,例如确定 3 个或更多按键是按下)用于JTextComponets
, 使用Document
, DocumentListener
,DocumentFilter
使用 KeyBinding 作为标准键,注意 - 必须检查 API 中是否实现了不需要的键(key_shortcut)
在这种情况下,将 DocumentFilter与Patern一起使用
简单的例子
import java.awt.*;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
public class TextAreaTest extends JFrame {
private static final long serialVersionUID = 1L;
private JTextArea textArea;
public TextAreaTest() {
textArea = new JTextArea();
textArea.setPreferredSize(new Dimension(60, 32));
textArea.setOpaque(true);
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
((AbstractDocument) textArea.getDocument()).setDocumentFilter(new DocumentFilter() {
@Override
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException {
//string = string.replaceAll("\\{", "\\{}");
super.insertString(fb, offset, string, attr);
}
@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
if (Pattern.compile("\\p{Space}").matcher(text).find()) {
System.exit(0);
}
//text = text.replaceAll("\\{", "\\{}");
super.replace(fb, offset, length, text, attrs);
}
});
textArea.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void changedUpdate(DocumentEvent e) {
update(e);
}
@Override
public void insertUpdate(DocumentEvent e) {
update(e);
}
@Override
public void removeUpdate(DocumentEvent e) {
update(e);
}
private void update(DocumentEvent e) {
List<String> lines = getLines(textArea);
String lastLine = lines.get(lines.size() - 1);
int tabbedTextWidth = Utilities.getTabbedTextWidth(new Segment(
lastLine.toCharArray(), 0, lastLine.length()), textArea.getFontMetrics(textArea.getFont()), 0, null, 0);
int lineHeight = getLineHeight(textArea);
if (lines.size() * lineHeight > textArea.getHeight() || tabbedTextWidth > textArea.getWidth()) {
System.out.println("Too big! Should refuse the update!");
}
}
});
getContentPane().add(textArea);
}
private static List<String> getLines(JTextArea textArea) {
int lineHeight = getLineHeight(textArea);
List<String> list = new ArrayList<String>();
for (int num = 0;; num++) {
int i = textArea.viewToModel(new Point(0, num * lineHeight));
int j = textArea.viewToModel(new Point(0, (num + 1) * lineHeight));
if (i == 0 && j == 0) {
continue;
}
if (textArea.getDocument().getLength() == i && i == j) {
break;
}
String s = removeTrailingNewLine(textArea.getText().substring(i, j));
list.add(s);
//System.out.println(i + " " + j + " = " + s);
}
return list;
}
private static int getLineHeight(JTextArea textArea) {
return textArea.getFontMetrics(textArea.getFont()).getHeight();
}
private static String removeTrailingNewLine(String s) {
if (s.endsWith("\n")) {
return s.substring(0, s.length() - 1);
} else {
return s;
}
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
TextAreaTest test = new TextAreaTest();
test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test.pack();
test.setVisible(true);
}
});
}
}