1、使用ctrl+z快捷键取消文本框修改

#include <QApplication>
#include <QLineEdit>
#include <QUndoStack>
#include <QVBoxLayout>int main(int argc, char *argv[]) {QApplication a(argc, argv);QWidget window;QVBoxLayout layout(&window);// 创建撤销框架QUndoStack undoStack;// 创建文本框QLineEdit lineEdit(&window);layout.addWidget(&lineEdit);// 将文本框的撤销操作绑定到撤销框架QObject::connect(&lineEdit, &QLineEdit::textChanged, [&undoStack, &lineEdit]() {undoStack.push(new QUndoCommand("Text Change", [&lineEdit]() {lineEdit.setText(lineEdit.text());}));});// 绑定撤销快捷键 Ctrl+ZQShortcut *undoShortcut = new QShortcut(QKeySequence(Qt::CTRL + Qt::Key_Z), &window);QObject::connect(undoShortcut, &QShortcut::activated, &undoStack, &QUndoStack::undo);window.setLayout(&layout);window.show();return a.exec();
}

2、在Qt中实现文本框的复制、粘贴、剪切和回退功能；可以通过重写文本框的键盘事件来实现

#include <QtWidgets>class MyTextEdit : public QTextEdit {
public:MyTextEdit(QWidget *parent = nullptr) : QTextEdit(parent) {}protected:void keyPressEvent(QKeyEvent *event) override {if (event->matches(QKeySequence::Copy)) {copy();} else if (event->matches(QKeySequence::Paste)) {paste();} else if (event->matches(QKeySequence::Cut)) {cut();} else if (event->matches(QKeySequence::Undo)) {undo();} else {QTextEdit::keyPressEvent(event);}}
};int main(int argc, char *argv[]) {QApplication app(argc, argv);MyTextEdit textEdit;textEdit.show();return app.exec();
}