在下面的代码中，我使用第一列的自定义单元格编辑器创建一个jtable，然后向表中添加撤消功能。当你运行程序时，程序允许你改变第一列中的值（通过附加＆＃34; d＆＃34;然后＆＃34; e＆＃34;来测试＆＃34; abc＆＃ 34;已经存在）。现在输入control-z（undo）并再次输入control-z。它按预期工作。但现在再次进入control-z（撤消）。这次＆＃34; abc＆＃34;被删除了。看起来swing系统正在设置列的初始值并为该操作创建撤消事件，然后用户可以撤消该操作。我的问题 - 我如何编写代码以便用户只能撤消用户的操作？
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.DefaultCellEditor;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JRootPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellEditor;
import javax.swing.undo.AbstractUndoableEdit;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;
import javax.swing.undo.UndoableEdit;
public class UndoExample extends JFrame {
private static final long serialVersionUID = 1L;;
static Boolean objEnableUndoRedoActions = true;
UndoExample rootFrame;
public UndoExample() {
// This procedure starts the whole thing off.
//Create table
final String[] tableColumns = {"Column 1", "Column 2"};
JTable tabUndoExample = new JTable(
new DefaultTableModel(null, tableColumns) {
private static final long serialVersionUID = 1L;
});
final DefaultTableModel tabUndoExampleModel = (DefaultTableModel) tabUndoExample
.getModel();
tabUndoExampleModel.addRow(new Object[]{"abc", true});
tabUndoExampleModel.addRow(new Object[]{"zyw", false});
// Create the undo/redo manager
UndoManager objUndoManager = new UndoManager();
// Create a cell editor
JTextField tfTabField = new JTextField();
TableCellEditor objEditor = new DefaultCellEditor(tfTabField);
// Make the cell editor the default editor for this table's first column
tabUndoExample.getColumnModel().getColumn(0)
.setCellEditor(objEditor);
// Create the undo action on the field's document for the column
tfTabField.getDocument().addUndoableEditListener(
new uelUndoRedoTableCellField(objUndoManager, tabUndoExample));
// Allow undo and redo to be entered by the user
UndoRedoSetKeys(this, "Example", objUndoManager);
tabUndoExample.setInheritsPopupMenu(true);
//Add the table to the frame and show the frame
this.add(tabUndoExample);
this.pack();
setLocationRelativeTo(null);
}
public static void main(final String[] args) {
// Launches the application. This is required syntax.
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
final UndoExample rootFrame = new UndoExample();
rootFrame.setVisible(true);
} catch (final Exception e) {
}
}
});
}
@SuppressWarnings("serial")
static class aueUndoRedoTableCellField extends AbstractUndoableEdit {
// Wrap the text edit action item as we need to add the table
// row and column information. This code is invoked when the
// code sees an undo event created and then later when the
// user requests an undo/redo.
JTable objTable = null;
UndoableEdit objUndoableEdit;
int objCol = -1;
int objRow = -1;
public aueUndoRedoTableCellField(UndoableEdit undoableEdit,
JTable table, int row, int col) {
super();
objUndoableEdit = undoableEdit;
objTable = table;
objCol = col;
objRow = row;
}
public void redo() throws CannotRedoException {
// When the user enters redo (or undo), this code sets
// that we are doing an redo (or undo), sets the cursor
// to the right location, and then does the undo (or redo)
// to the table cell.
UndoRedoManagerSetEnabled(false);
super.redo();
@SuppressWarnings("unused")
boolean success = objTable.editCellAt(objRow, objCol);
objTable.changeSelection(objRow, objCol, false, false);
objUndoableEdit.redo();
UndoRedoManagerSetEnabled(true);
}
public void undo() throws CannotUndoException {
super.undo();
UndoRedoManagerSetEnabled(false);
@SuppressWarnings("unused")
boolean success = objTable.editCellAt(objRow, objCol);
objTable.changeSelection(objRow, objCol, false, false);
objUndoableEdit.undo();
UndoRedoManagerSetEnabled(true);
}
}
static class aUndoRedo extends AbstractAction {
// This code is bound to the undo/redo keystrokes and tells
// Java what commands to run when the keys are later entered
// by the user.
private static final long serialVersionUID = 1L;
Boolean objUndo = true;
UndoManager objUndoManager = null;
final String objLocation;
public aUndoRedo(Boolean Undo, UndoManager undoManager, String location) {
super();
objUndo = Undo;
objUndoManager = undoManager;
objLocation = location;
}
@Override
public void actionPerformed(ActionEvent ae) {
try {
// See if operation allowed
if (!objUndoManager.canUndo() && objUndo
|| !objUndoManager.canRedo() && !objUndo)
return;
UndoRedoManagerSetEnabled(false);
if (objUndo) {
objUndoManager.undo();
} else {
objUndoManager.redo();
}
UndoRedoManagerSetEnabled(true);
// Catch errors and let user know
} catch (Exception e) {
UndoRedoManagerSetEnabled(true);
}
}
}
static class uelUndoRedoTableCellField implements UndoableEditListener {
// This action is called when the user changes the table's
// text cell. It saves the change for later undo/redo.
private UndoManager objUndoManager = null;
private JTable objTable = null;
public uelUndoRedoTableCellField(UndoManager undoManager,
JTable table) {
objUndoManager = undoManager;
objTable = table;
}
@Override
public void undoableEditHappened(UndoableEditEvent e) {
// Remember the edit but only if the code isn't doing
// an undo or redo currently.
if (UndoRedoManagerIsEnabled()) {
objUndoManager.addEdit(new aueUndoRedoTableCellField(e
.getEdit(), objTable, objTable.getSelectedRow(),
objTable.getSelectedColumn()));
}
}
}
static public Boolean UndoRedoManagerIsEnabled() {
// See if we are currently doing an undo/redo.
// Return true if so.
return objEnableUndoRedoActions;
}
static public void UndoRedoManagerSetEnabled(Boolean state) {
// Set the state of whether we are in undo/redo code.
objEnableUndoRedoActions = state;
}
static void UndoRedoSetKeys(JFrame frame, final String location, UndoManager undoManager) {
// Allow undo and redo to be called via these keystrokes for this dialog
final String cntl_y = "CNTL_Y";
final KeyStroke ksCntlY = KeyStroke.getKeyStroke("control Y");
final String cntl_z = "CNTL_Z";
final KeyStroke ksCntlZ = KeyStroke.getKeyStroke("control Z");
JRootPane root = frame.getRootPane();
root.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
.put(ksCntlZ, cntl_z);
root.getActionMap().put(
cntl_z,
new aUndoRedo(true, undoManager, location));
root.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
.put(ksCntlY, cntl_y);
root.getActionMap().put(
cntl_y,
new aUndoRedo(false, undoManager, location));
}
}
答案 0 :(得分：1)
当您按某个键时，会发生一系列事情。 JTable处理键击，它检查单元格是否可编辑（如TableModel），然后如果事件应该编辑单元格，它会询问编辑器当前选定的单元格（{ {1}}）。
如果此方法返回CellEditor#isCellEditable(EventObject)，则编辑器已准备好，true的值将应用于编辑器（即调用TableModel），并将编辑器添加到setText，最后，触发编辑模式的事件被重新调度到编辑器，在你的情况下是 Ctrl + Z ，然后触发并撤消事件，返回编辑器的初始状态（在JTable被调用之前）。
您可以尝试使用类似......
的内容setText以防止在发生特定键击时将TableCellEditor objEditor = new DefaultCellEditor(tfTabField) {
@Override
public boolean isCellEditable(EventObject anEvent) {
boolean isEditable = super.isCellEditable(anEvent); //To change body of generated methods, choose Tools | Templates.
if (isEditable && anEvent instanceof KeyEvent) {
KeyEvent ke = (KeyEvent) anEvent;
if (ke.isControlDown() && ke.getKeyCode() == KeyEvent.VK_Z) {
isEditable = false;
}
}
return isEditable;
}
};
置于编辑状态
<强>更新
基于Andrew JTextArea setText() & UndoManager的答案，我设计了一个可配置的＆＃34; JTable可以设置为忽略可撤消的操作，例如......
UndoableEditListener现在，您将拥有自己的设备import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;
public class FixedField {
public static void main(String[] args) {
new FixedField();
}
public FixedField() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class UndoableEditHandler implements UndoableEditListener {
private static final int MASK
= Toolkit.getDefaultToolkit().getMenuShortcutKeyMask();
private UndoManager undoManager = new UndoManager();
private boolean canUndo = true;
public UndoableEditHandler(JTextField field) {
Document doc = field.getDocument();
doc.addUndoableEditListener(this);
field.getActionMap().put("Undo", new AbstractAction("Undo") {
@Override
public void actionPerformed(ActionEvent evt) {
try {
if (undoManager.canUndo()) {
undoManager.undo();
}
} catch (CannotUndoException e) {
System.out.println(e);
}
}
});
field.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_Z, MASK), "Undo");
field.getActionMap().put("Redo", new AbstractAction("Redo") {
@Override
public void actionPerformed(ActionEvent evt) {
try {
if (undoManager.canRedo()) {
undoManager.redo();
}
} catch (CannotRedoException e) {
System.out.println(e);
}
}
});
field.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_Y, MASK), "Redo");
}
@Override
public void undoableEditHappened(UndoableEditEvent e) {
if (canUndo()) {
undoManager.addEdit(e.getEdit());
}
}
public void setCanUndo(boolean canUndo) {
this.canUndo = canUndo;
}
public boolean canUndo() {
return canUndo;
}
}
public class TestPane extends JPanel {
public TestPane() {
JTextField field = new JTextField(10);
UndoableEditHandler handler = new UndoableEditHandler(field);
handler.setCanUndo(false);
field.setText("Help");
handler.setCanUndo(true);
add(field);
}
}
}
以支持此功能，例如......
TableCellEditor