本文介绍了使用documentFilter过滤出制表符的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
因此，我有一个带有JTextArea和DocumentFilter的程序.它应该(除其他外)过滤掉制表符，并阻止它们完全输入到JTextArea中.
So, I have a program with JTextArea with DocumentFilter. It should (among other things) filter out tab characters and prevent them to be entered in the JTextArea completely.
好吧，当我键入文字时效果很好，但是我仍然可以将其粘贴.根据代码，我应该不能...
Well, it works well when I type, but I can still paste it in. i shouldn't be able to, according to the code...
以下是一种SSCCE.只需运行它，按ctrl + n并输入.所有彩色文件都是具有相同DocumentFilter的JTextAreas.过滤器本身是第一类(DefaultDocFilter)，只有您需要研究的内容.
Below is kind of a SSCCE. Just run it, press ctrl+n and enter. All the colored fileds are JTextAreas with same DocumentFilter. The filter itself is the first class (DefaultDocFilter), only thing you need to look into.
package core;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Properties;
import java.util.ResourceBundle;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.border.Border;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.JTextComponent;
class DefaultDocFilter extends DocumentFilter
{
public void insertString(FilterBypass fb, int offs,String str, AttributeSet a) throws BadLocationException
{
if ((fb.getDocument().getLength() + str.length()) <= 200)
{
str.replaceAll("\n", " ");
str.replaceAll("\t", " ");
System.out.print(str);
fb.insertString(offs, str, a);
}
else
{
int spaceLeft = 200 - fb.getDocument().getLength();
if (spaceLeft <= 0)
return;
str.substring(0, spaceLeft);
str.replaceAll("\n", " ");
str.replaceAll("\t", " ");
fb.insertString(offs, str, a);
}
}
public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a) throws BadLocationException
{
if (str.equals("\n") || str.equals("\t"))
{
str = "";
}
if ((fb.getDocument().getLength() + str.length() - length) <= 200)
{
str.replaceAll("\n", " ");
str.replaceAll("\t", " ");
fb.replace(offs, length, str, a);
}
else
{
int spaceLeft = 200 - fb.getDocument().getLength() + length;
if (spaceLeft <= 0)
return;
fb.replace(offs, length, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
}
}
}
@SuppressWarnings("serial")
class DefaultFont extends Font
{
public DefaultFont()
{
super("Arial", PLAIN, 20);
}
}
@SuppressWarnings("serial")
class Page extends JPanel
{
public JPanel largePage;
public int content;
public Page(JPanel panel, int index)
{
largePage = new JPanel();
largePage.setLayout(new BoxLayout(largePage, BoxLayout.Y_AXIS));
largePage.setMaximumSize(new Dimension(794, 1123));
largePage.setPreferredSize(new Dimension(794, 1123));
largePage.setAlignmentX(Component.CENTER_ALIGNMENT);
largePage.setBackground(Color.WHITE);
largePage.add(new Box.Filler(new Dimension(0, 96), new Dimension(0, 96), new Dimension(0, 96)));
setMaximumSize(new Dimension(556, 931));
setBackground(Color.LIGHT_GRAY);
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
add(new Box.Filler(new Dimension(556, 0), new Dimension(556, 931), new Dimension(556, 931)));
largePage.add(this);
largePage.add(new Box.Filler(new Dimension(0, 96), new Dimension(0, 96), new Dimension(0, 96)));
panel.add(largePage, index);
panel.add(new Box.Filler(new Dimension(0, 40), new Dimension(0, 40), new Dimension(0, 40)));
content = 0;
Main.pages.add(this);
}
}
@SuppressWarnings("serial")
class Heading extends JTextArea
{
public boolean type;
public AbstractDocument doc;
public ArrayList<JPanel/*Question*/> questions;
public ArrayList<JPanel/*List*/> list;
public Heading(boolean segment, Page page)
{
type = segment;
setBackground(Color.RED);
setFont(new Font("Arial", Font.BOLD, 20));
Border in = BorderFactory.createDashedBorder(Color.BLACK);
Border out = BorderFactory.createMatteBorder(0, 0, 10, 0, Color.WHITE);
setBorder(BorderFactory.createCompoundBorder(out, in));
setLineWrap(true);
setWrapStyleWord(true);
setText("Heading 1 Heading 1 Heading 1 Heading 1");
doc = (AbstractDocument)this.getDocument();
doc.setDocumentFilter(new DefaultDocFilter());
page.add(this, 0);
page.content++;
if (type)
{
questions = new ArrayList<JPanel>();
}
else
{
list = new ArrayList<JPanel>();
}
}
}
@SuppressWarnings("serial")
class Question extends JPanel
{
public JPanel questionArea, numberArea, answerArea;
public JLabel number;
public JTextArea question;
public AbstractDocument doc;
public Question(Page page, int pageNum, int index)
{
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.WHITE));
questionArea = new JPanel();
questionArea.setLayout(new BoxLayout(questionArea, BoxLayout.X_AXIS));
questionArea.setBorder(BorderFactory.createMatteBorder(0, 0, 8, 0, Color.WHITE));
numberArea = new JPanel();
numberArea.setLayout(new BorderLayout());
numberArea.setBackground(Color.WHITE);
number = new JLabel(pageNum+". ", JLabel.RIGHT);
number.setMinimumSize(new Dimension(100, 20));
number.setPreferredSize(new Dimension(100, 20));
number.setMaximumSize(new Dimension(100, 20));
number.setFont(new Font("Arial", Font.PLAIN, 17));
numberArea.add(number, BorderLayout.NORTH);
questionArea.add(numberArea);
question = new JTextArea();
question.setFont(new Font("Arial", Font.PLAIN, 17));
question.setBorder(BorderFactory.createDashedBorder(Color.BLACK));
question.setLineWrap(true);
question.setWrapStyleWord(true);
question.setBackground(Color.GREEN);
question.setText("Is this the first question?");
doc = (AbstractDocument)question.getDocument();
doc.setDocumentFilter(new DefaultDocFilter());
questionArea.add(question);
add(questionArea);
answerArea = new JPanel();
answerArea.setLayout(new BoxLayout(answerArea, BoxLayout.Y_AXIS));
add(answerArea);
page.add(this, index);
page.content++;
}
}
@SuppressWarnings("serial")
class Answer extends JPanel
{
public JPanel letterArea;
public JLabel letter;
public JTextArea answer;
public AbstractDocument doc;
public Answer(Question q, int index)
{
setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
letterArea = new JPanel();
letterArea.setLayout(new BorderLayout());
letterArea.setBackground(Color.WHITE);
letter = new JLabel((char)(index+96)+") ", JLabel.RIGHT);
letter.setMinimumSize(new Dimension(150, 20));
letter.setPreferredSize(new Dimension(150, 20));
letter.setMaximumSize(new Dimension(150, 20));
letter.setFont(new Font("Arial", Font.PLAIN, 17));
letterArea.add(letter, BorderLayout.NORTH);
add(letterArea);
answer = new JTextArea();
answer.setFont(new Font("Arial", Font.PLAIN, 17));
Border in = BorderFactory.createDashedBorder(Color.BLACK);
Border out = BorderFactory.createMatteBorder(0, 0, 5, 0, Color.WHITE);
answer.setBorder(BorderFactory.createCompoundBorder(out, in));
answer.setLineWrap(true);
answer.setWrapStyleWord(true);
answer.addKeyListener(new KeyListener()
{
@Override
public void keyPressed(KeyEvent arg0)
{
System.out.print(((JTextComponent) arg0.getSource()).getText());
if (arg0.getKeyCode() == KeyEvent.VK_ENTER)
{
String JLabelText = ((JLabel) ((JPanel) ((JPanel) ((Component) arg0.getSource()).getParent()).getComponent(0)).getComponent(0)).getText();
int ansNum = (int)JLabelText.charAt(0)-95;
if (ansNum < 6)
{
Answer k = new Answer((Question) ((JTextArea) arg0.getSource()).getParent().getParent().getParent(), ansNum);
k.answer.grabFocus();
Main.mWindow.repaint();
Main.mWindow.validate();
}
}
}
public void keyReleased(KeyEvent arg0) {}
public void keyTyped(KeyEvent arg0) {}
});
doc = (AbstractDocument)answer.getDocument();
doc.setDocumentFilter(new DefaultDocFilter());
answer.setBackground(Color.PINK);
add(answer);
q.answerArea.add(this, index-1);
}
}
public class Main
{
public static Properties config;
public static Locale currentLocale;
public static ResourceBundle lang;
public static JFrame mWindow;
public static JMenuBar menu;
public static JMenu menuFile, menuEdit;
public static JMenuItem itmNew, itmClose, itmLoad, itmSave, itmSaveAs, itmExit, itmCut, itmCopy, itmPaste, itmProperties;
public static JDialog newDoc;
public static JLabel newDocText1, newDocText2;
public static JRadioButton questions, list;
public static ButtonGroup newDocButtons;
public static JButton newDocOk;
public static Boolean firstSegment;
public static JPanel workspace;
public static JScrollPane scroll;
public static ArrayList<Page> pages;
public static void newDocumentForm()
{
//new document dialog
mWindow.setEnabled(false);
newDoc = new JDialog(mWindow, "newDoc");
newDoc.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
newDoc.addWindowListener(new WindowListener ()
{
public void windowActivated(WindowEvent arg0) {}
public void windowClosing(WindowEvent arg0)
{
mWindow.toFront();
newDocText1 = null;
newDocText2 = null;
questions = null;
list = null;
newDocButtons = null;
newDocOk = null;
newDoc.dispose();
mWindow.setEnabled(true);
}
public void windowClosed(WindowEvent arg0) {}
public void windowDeactivated(WindowEvent arg0) {}
public void windowDeiconified(WindowEvent arg0) {}
public void windowIconified(WindowEvent arg0) {}
public void windowOpened(WindowEvent arg0) {}
});
newDoc.setSize(400, 200);
newDoc.setLocationRelativeTo(null);
newDoc.setResizable(false);
newDoc.setLayout(null);
newDoc.setVisible(true);
newDocText1 = new JLabel("newDocText1");
newDocText1.setBounds(5, 0, 400, 20);
newDocText2 = new JLabel("newDocText2");
newDocText2.setBounds(5, 20, 400, 20);
newDoc.add(newDocText1);
newDoc.add(newDocText2);
firstSegment = true;
questions = new JRadioButton("questions");
questions.setSelected(true);
questions.setFocusPainted(false);
questions.setBounds(10, 60, 400, 20);
questions.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
firstSegment = true;
}
});
list = new JRadioButton("list");
list.setFocusPainted(false);
list.setBounds(10, 80, 400, 20);
list.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
firstSegment = false;
}
});
newDoc.add(questions);
newDoc.add(list);
newDocButtons = new ButtonGroup();
newDocButtons.add(questions);
newDocButtons.add(list);
newDocOk = new JButton("ok");
newDocOk.addKeyListener(new KeyListener()
{
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_ENTER)
{
newDocOk.doClick();
}
}
public void keyReleased(KeyEvent e) {}
public void keyTyped(KeyEvent e) {}
});
newDocOk.setFocusPainted(false);
newDocOk.setBounds(160, 120, 80, 40);
newDocOk.setMnemonic(KeyEvent.VK_ACCEPT);
newDocOk.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
createNewDocument();
}
});
newDoc.add(newDocOk);
newDocOk.requestFocus();
}
public static void createNewDocument()
{
//dispose of new document dialog
mWindow.toFront();
newDocText1 = null;
newDocText2 = null;
questions = null;
list = null;
newDocButtons = null;
newDocOk = null;
newDoc.dispose();
mWindow.setEnabled(true);
//create document display
workspace = new JPanel();
workspace.setLayout(new BoxLayout(workspace, BoxLayout.PAGE_AXIS));
workspace.add(new Box.Filler(new Dimension(0, 40), new Dimension(0, 40), new Dimension(0, 40)));
workspace.setBackground(Color.BLACK);
scroll = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scroll.getVerticalScrollBar().setUnitIncrement(20);
scroll.setViewportView(workspace);
pages = new ArrayList<Page>();
Page p = new Page(workspace, 1);
new Heading(true, p);
Question q = new Question(p, 1, 1);
new Answer(q, 1);
mWindow.add(scroll, BorderLayout.CENTER);
mWindow.repaint();
mWindow.validate();
}
public static void main(String[] args) throws FileNotFoundException, IOException
{
//create main window
mWindow = new JFrame("title");
mWindow.setSize(1000, 800);
mWindow.setMinimumSize(new Dimension(1000, 800));
mWindow.setLocationRelativeTo(null);
mWindow.setLayout(new BorderLayout());
mWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mWindow.setVisible(true);
//create menu bar
menu = new JMenuBar();
menuFile = new JMenu("file");
menuEdit = new JMenu("edit");
itmNew = new JMenuItem("new");
itmNew.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N, ActionEvent.CTRL_MASK));
itmNew.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
newDocumentForm();
}
});
itmClose = new JMenuItem("close");
itmClose.setActionCommand("Close");
itmClose.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_W, ActionEvent.CTRL_MASK));
itmLoad = new JMenuItem("load");
itmLoad.setActionCommand("Load");
itmLoad.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_L, ActionEvent.CTRL_MASK));
itmSave = new JMenuItem("save");
itmSave.setActionCommand("Save");
itmSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, ActionEvent.CTRL_MASK));
itmSaveAs = new JMenuItem("saveAs");
itmSaveAs.setActionCommand("SaveAs");
itmExit = new JMenuItem("exit");
itmExit.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
//Add confirmation window!
System.exit(0);
}
});
itmCut = new JMenuItem("cut");
itmCut.setActionCommand("Cut");
itmCut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X, ActionEvent.CTRL_MASK));
itmCopy = new JMenuItem("copy");
itmCopy.setActionCommand("Copy");
itmCopy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C, ActionEvent.CTRL_MASK));
itmPaste = new JMenuItem("paste");
itmPaste.setActionCommand("Paste");
itmPaste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V, ActionEvent.CTRL_MASK));
itmProperties = new JMenuItem("properties");
itmProperties.setActionCommand("properties");
itmProperties.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_P, ActionEvent.CTRL_MASK));
menuFile.add(itmNew);
menuFile.add(itmClose);
menuFile.addSeparator();
menuFile.add(itmLoad);
menuFile.addSeparator();
menuFile.add(itmSave);
menuFile.add(itmSaveAs);
menuFile.addSeparator();
menuFile.add(itmExit);
menuEdit.add(itmCut);
menuEdit.add(itmCopy);
menuEdit.add(itmPaste);
menuEdit.addSeparator();
menuEdit.add(itmProperties);
menu.add(menuFile);
menu.add(menuEdit);
//create actionListener for menus
mWindow.add(menu, BorderLayout.NORTH);
mWindow.repaint();
mWindow.validate();
}
}
推荐答案
为什么不将String分配给DocumentFilter
str = str.replaceAll()?
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