Qt之菜单栏中的剪切、拷贝、粘贴

今天来实现一下记事本中的剪切、拷贝、粘贴等功能

一、添加菜单栏

　　 QMenu *editMenu = menuBar()->addMenu("Edit");
    QToolBar *editToolBar = addToolBar("Edit");

    QAction *cutAct = new QAction(QIcon(":/images/cut.png"), "Cut", this);

    cutAct->setShortcuts(QKeySequence::Cut);
    cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                            "clipboard"));
    connect(cutAct, &QAction::triggered, textEdit, &QPlainTextEdit::cut);
    editMenu->addAction(cutAct);
    editToolBar->addAction(cutAct);

    QAction *copyAct = new QAction(QIcon(":/images/copy.png"), "Copy", this);
    copyAct->setShortcuts(QKeySequence::Copy);
    copyAct->setStatusTip("Copy the current selection's contents to the "
                            "clipboard");
    connect(copyAct, &QAction::triggered, textEdit, &QPlainTextEdit::copy);
    editMenu->addAction(copyAct);
    editToolBar->addAction(copyAct);

    QAction *pasteAct = new QAction(QIcon(":/images/paste.png"), "Paste", this);
    pasteAct->setShortcuts(QKeySequence::Paste);
    pasteAct->setStatusTip("Paste the clipboard's contents into the current "
                              "selection");
    connect(pasteAct, &QAction::triggered, textEdit, &QPlainTextEdit::paste);
    editMenu->addAction(pasteAct);
    editToolBar->addAction(pasteAct);

    menuBar()->addSeparator();

    QMenu *helpMenu = menuBar()->addMenu("Help");
    QAction *aboutAct = helpMenu->addAction("&About", this, &MainWindow::about);
    aboutAct->setStatusTip("Show the application's About box");

    QAction *aboutQtAct = helpMenu->addAction("About &Qt", qApp, &QApplication::aboutQt);
    aboutQtAct->setStatusTip("Show the Qt library's About box");

    cutAct->setEnabled(false);
    copyAct->setEnabled(false);
    connect(textEdit, &QPlainTextEdit::copyAvailable, cutAct, &QAction::setEnabled);
    connect(textEdit, &QPlainTextEdit::copyAvailable, copyAct, &QAction::setEnabled);
    
    //创建状态栏
    statusBar()->showMessage(tr("Ready"));