JTextArea setText（）和UndoManager

JTextArea setText（）和UndoManager

您可以尝试如下 *** 作：

//Works fine for me on Windows 7 x64 using JDK 1.7.0_60:import java.awt.*;import java.awt.event.*;import java.util.*;import javax.swing.*;import javax.swing.event.*;import javax.swing.text.*;import javax.swing.undo.*;public final class UndoManagerTest {  private final JTextField textField0 = new JTextField("default");  private final JTextField textField1 = new JTextField();  private final UndoManager undoManager0 = new UndoManager();  private final UndoManager undoManager1 = new UndoManager();  public JComponent makeUI() {    textField1.setdocument(new CustomUndoPlaindocument());    textField1.setText("aaaaaaaaaaaaaaaaaaaaa");    textField0.getdocument().addUndoableEditListener(undoManager0);    textField1.getdocument().addUndoableEditListener(undoManager1);    JPanel p = new JPanel();    p.add(new JButton(new AbstractAction("undo") {      @Override public void actionPerformed(ActionEvent e) {        if (undoManager0.canUndo()) {          undoManager0.undo();        }        if (undoManager1.canUndo()) {          undoManager1.undo();        }      }    }));    p.add(new JButton(new AbstractAction("redo") {      @Override public void actionPerformed(ActionEvent e) {        if (undoManager0.canRedo()) {          undoManager0.redo();        }        if (undoManager1.canRedo()) {          undoManager1.redo();        }      }    }));    p.add(new JButton(new AbstractAction("setText(new Date())") {      @Override public void actionPerformed(ActionEvent e) {        String str = new Date().toString();        textField0.setText(str);        textField1.setText(str);      }    }));    Box box = Box.createVerticalBox();    box.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));    box.add(makePanel("Default", textField0));    box.add(Box.createVerticalStrut(5));    box.add(makePanel("replace ignoring undo", textField1));    JPanel pp = new JPanel(new BorderLayout());    pp.add(box, BorderLayout.NORTH);    pp.add(p, BorderLayout.SOUTH);    return pp;  }  private static JPanel makePanel(String title, JComponent c) {    JPanel p = new JPanel(new BorderLayout());    p.setBorder(BorderFactory.createTitledBorder(title));    p.add(c);    return p;  }  public static void main(String[] args) {    EventQueue.invokeLater(new Runnable() {      @Override public void run() {        createAndShowGUI();      }    });  }  public static void createAndShowGUI() {    Jframe f = new Jframe();    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);    f.getContentPane().add(new UndoManagerTest().makeUI());    f.setSize(320, 240);    f.setLocationRelativeTo(null);    f.setVisible(true);  }}class CustomUndoPlaindocument extends Plaindocument {  private CompoundEdit compoundEdit;  @Override protected void fireUndoableEditUpdate(UndoableEditEvent e) {    if (compoundEdit == null) {      super.fireUndoableEditUpdate(e);    } else {      compoundEdit.addEdit(e.getEdit());    }  }  @Override public void replace(      int offset, int length,      String text, AttributeSet attrs) throws BadLocationException {    if (length == 0) {      System.out.println("insert");      super.replace(offset, length, text, attrs);    } else {      System.out.println("replace");      compoundEdit = new CompoundEdit();      super.fireUndoableEditUpdate(new UndoableEditEvent(this, compoundEdit));      super.replace(offset, length, text, attrs);      compoundEdit.end();      compoundEdit = null;    }  }}