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Qt学习1

2024-07-25 15:03:20   222人阅读

Action 的用法

首先在头文件的 private 中加：

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QMenu *fileMenu;
QMenu *editMenu;
QMenu *helpMenu;


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void MainWindow::createActions()
//! [17] //! [18]
{
    newAct = new QAction(QIcon(":/images/new.png"), tr("&New"), this);
    newAct->setShortcuts(QKeySequence::New);
    newAct->setStatusTip(tr("Create a new file"));
    connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));
 
//! [19]
    openAct = new QAction(QIcon(":/images/open.png"), tr("&Open..."), this);
    openAct->setShortcuts(QKeySequence::Open);
    openAct->setStatusTip(tr("Open an existing file"));
    connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
}

menubar

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fileMenu = menuBar()->addMenu(tr("&File"));
    fileMenu->addAction(newAct);
//! [28]
    fileMenu->addAction(openAct);
//! [28]
    fileMenu->addAction(saveAct);
//! [26]
    fileMenu->addAction(saveAsAct);
    fileMenu->addSeparator();
    fileMenu->addAction(exitAct);
 
    editMenu = menuBar()->addMenu(tr("&Edit"));
    editMenu->addAction(cutAct);
    editMenu->addAction(copyAct);
    editMenu->addAction(pasteAct);

 toolbar

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fileToolBar = addToolBar(tr("File"));
    fileToolBar->addAction(newAct);
//! [29] //! [31]
    fileToolBar->addAction(openAct);
//! [31]
    fileToolBar->addAction(saveAct);
 
    editToolBar = addToolBar(tr("Edit"));
    editToolBar->addAction(cutAct);
    editToolBar->addAction(copyAct);
    editToolBar->addAction(pasteAct);

Qsetting 

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QSettings settings("QtProject", "Application Example");
settings.setValue("pos", pos());
settings.setValue("size", size());
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QSettings settings("QtProject", "Application Example");
QPoint pos = settings.value("pos", QPoint(200, 200)).toPoint();
QSize size = settings.value("size", QSize(400, 400)).toSize();

打开文本文件

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void MainWindow::open()
//! [7] //! [8]
{
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty())
            loadFile(fileName);
    }
}
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void MainWindow::loadFile(const QString &fileName)
//! [42] //! [43]
{
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly | QFile::Text)) {
        QMessageBox::warning(this, tr("Application"),
                             tr("Cannot read file %1:\n%2.")
                             .arg(fileName)
                             .arg(file.errorString()));
        return;
    }
 
    QTextStream in(&file);
#ifndef QT_NO_CURSOR
    QApplication::setOverrideCursor(Qt::WaitCursor);
#endif
    textEdit->setPlainText(in.readAll());
#ifndef QT_NO_CURSOR
    QApplication::restoreOverrideCursor();
#endif
 
    setCurrentFile(fileName);
    statusBar()->showMessage(tr("File loaded"), 2000);
}

文本文件保存

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bool MainWindow::saveAs()
//! [11] //! [12]
{
    QString fileName = QFileDialog::getSaveFileName(this);
    if (fileName.isEmpty())
        return false;
 
    return saveFile(fileName);
}
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bool MainWindow::saveFile(const QString &fileName)
//! [44] //! [45]
{
    QFile file(fileName);
    if (!file.open(QFile::WriteOnly | QFile::Text)) {
        QMessageBox::warning(this, tr("Application"),
                             tr("Cannot write file %1:\n%2.")
                             .arg(fileName)
                             .arg(file.errorString()));
        return false;
    }
 
    QTextStream out(&file);
#ifndef QT_NO_CURSOR
    QApplication::setOverrideCursor(Qt::WaitCursor);
#endif
    out << textEdit->toPlainText();
#ifndef QT_NO_CURSOR
    QApplication::restoreOverrideCursor();
#endif
 
    setCurrentFile(fileName);
    statusBar()->showMessage(tr("File saved"), 2000);
    return true;
}




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