我正在尝试在JTextArea
中实现撤消功能。用Google搜索教程,并按照其中一个教程编写了以下代码。按下Ctrl + Z键会触发事件。它对我不起作用。我想念什么吗?
private void undoActionPerformed(java.awt.event.ActionEvent evt) {
Document doc = editorTextArea.getDocument();
final UndoManager undo = new UndoManager();
doc.addUndoableEditListener(new UndoableEditListener() {
@Override
public void undoableEditHappened(UndoableEditEvent e) {
undo.addEdit(e.getEdit());
}
});
}
最佳答案
从您的榜样来看,很难知道您做了多少,但是我能够做到这一点...
private UndoManager undoManager;
// In the constructor
undoManager = new UndoManager();
Document doc = textArea.getDocument();
doc.addUndoableEditListener(new UndoableEditListener() {
@Override
public void undoableEditHappened(UndoableEditEvent e) {
System.out.println("Add edit");
undoManager.addEdit(e.getEdit());
}
});
InputMap im = textArea.getInputMap(JComponent.WHEN_FOCUSED);
ActionMap am = textArea.getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_Z, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()), "Undo");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_Y, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()), "Redo");
am.put("Undo", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
try {
if (undoManager.canUndo()) {
undoManager.undo();
}
} catch (CannotUndoException exp) {
exp.printStackTrace();
}
}
});
am.put("Redo", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
try {
if (undoManager.canRedo()) {
undoManager.redo();
}
} catch (CannotUndoException exp) {
exp.printStackTrace();
}
}
});