一、打开文件夹返回文件名

代码如下：

void MainWindow::on_btn_open_csvFile_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(
            this,tr("选择要打开的文件"),
            QDir::currentPath(),
            tr("文本文件(*.txt);;所有文件(*.*)"));
    if (!fileName.isEmpty())
    {
        this->fileName = fileName;
        qDebug()<<"filename:"<<fileName;
    }

}

二、CSV文件格式如图：

三、QT读CSV文件，代码如下

void MainWindow::on_btn_get_csv22_clicked()
{
    QVector<double> x, y,y2;

    QStringList csvList;
    csvList.clear();


    //解析CSV文件

    QFile csvFile(this->fileName22);

    if(csvFile.open(QIODevice::ReadWrite))
    {
        QTextStream stream(&csvFile);
        while(!stream.atEnd())
        {
            csvList.push_back(stream.readLine());
        }
        csvFile.close();
    }
    else
    {
        QMessageBox::about(nullptr,"csv 文件","打开失败");
    }

    int i = 0;
    Q_FOREACH(QString str,csvList)
    {
        i  = i + 1;
        QStringList valsplit = str.split(",");
        if(i>3)
        {
            x.push_back(valsplit[0].toDouble());
            y.push_back(valsplit[1].toDouble());
            y2.push_back(valsplit[2].toDouble());
        }

    }


}

四、QT写CSV文件，代码如下：

void MainWindow::on_btn_geneate_csvFile22_clicked()
{
    QDateTime datetime = QDateTime::currentDateTime();
    QString timestr = datetime.toString("ddHHmmzzz");
//    QFile data(QString("E:\QT\qcptest2\") + "two" + timestr + ".csv");            // 以上两行用时间戳作为文件名
    this->fileName = "E:\QT\qcptest2\cos.csv";
    QFile data(this->fileName22);
    if(data.open(QFile::WriteOnly | QFile::Truncate))        // 打开文件
    {
        QTextStream out(&data);    // 输入流
        double t = 0;
        double y1;
        double y2;
        double intv = 1;
        for (int i = 0; i < 100; ++i)
        {
            y1 = qSin(t);
            y2 = qCos(t);
            out <<QString::number(t)<<"," << QString::number(y1)<<"," << QString::number(y2)<<","<< "
";

            t = t + intv;
        }
    }
    data.close();

}