Seven, Qt's read, write files

Common code ready

/**
 * @brief 读文件
 */
QString MyMainWindow::openFile()
{
    QString curPath = QDir::currentPath();
    QString dlgTitle = "打开一个文件";
    QString filter = "程序文件(*.h *.cpp);;文本文件(*.txt);;所有文件(*.*)";
    QString fileName = QFileDialog::getOpenFileName(this, dlgTitle, curPath, filter);
    if (fileName.isEmpty())
        return NULL;
    return fileName;
}
/**
 * @brief 写文件
 */
QString MyMainWindow::saveFile()
{
    QString curPath = QDir::currentPath();
    QString dlgTitle = "打开一个文件";
    QString filter = "程序文件(*.h *.cpp);;文本文件(*.txt);;所有文件(*.*)";
    QString fileName = QFileDialog::getSaveFileName(this, dlgTitle, curPath, filter);
    if (fileName.isEmpty())
        return NULL;
    return fileName;
}

A way: in a Stream reads, writes

bool MyMainWindow::openTextByTextStream(const QString &fileName)
{
    QFile file(fileName);
    if (!file.exists())
        return false;
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return false;
    QTextStream stream(&file);
    //自动检测 Unicode，否则汉字会出现乱码
    stream.setAutoDetectUnicode(true);
    ui->plainTextEdit->clear();
    while (!stream.atEnd()) {
        ui->plainTextEdit->appendPlainText(stream.readLine());
    }
    file.close();
    ui->tabWidget->setCurrentIndex(1);
    return true;
}

bool MyMainWindow::saveTextByTextStream(const QString &fileName)
{
    QFile file(fileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
        return false;
    QTextStream stream(&file);
    //自动检测 Unicode，否则汉字会出现乱码
    stream.setAutoDetectUnicode(true);
    QString str = ui->plainTextEdit->toPlainText();
    stream << str;
    file.close();
    return true;
}

Second way: QFile manner to read, write,

/**
 * @brief 读文件
 */
bool MyMainWindow::openTextByIoDevice(const QString &fileName)
{
    QFile file(fileName);
    if (!file.exists())
        return false;
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return false;
    ui->plainTextEdit->setPlainText(file.readAll());
    file.close();
    ui->tabWidget->setCurrentIndex(0);
    return true;
}
/**
 * @brief 写文件
 */
bool MyMainWindow::saveTextByIoDevice(const QString &fileName)
{
    QFile file(fileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
        return false;
    QString str = ui->plainTextEdit->toPlainText();
    QByteArray byteArr = str.toUtf8();
    file.write(byteArr, byteArr.length());
    file.close();
    ui->tabWidget->setCurrentIndex(0);
    return true;
}