QFileDialog&QSettings 记住上次打开的路径

 记住上次打开的路径：

    QSettings setting;

    QString   LastPath = setting.value("kaeConfPath").toString();

    QString AbsPath = QFileInfo(LastPath).absolutePath();

    QDir    lastDir(AbsPath);

    if (LastPath.isEmpty()) {  //路径为空

        LastPath = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);

    } else if (!lastDir.exists()) {  //文件夹不存在

        bool rec = lastDir.mkpath(AbsPath);

        if (!rec) {  //创建失败,无权限

            LastPath = QStandardPaths::writableLocation(QStandardPaths::HomeLocation);

        }

    }

    QString kaeConfPath = QFileDialog::getExistingDirectory(

        this, tr("选择文件夹"), LastPath, QFileDialog::DontResolveSymlinks | QFileDialog::DontUseNativeDialog);

    if (kaeConfPath.isEmpty()) {

        return;

    }

    setting.setValue("kaeConfPath", kaeConfPath);

    setting.sync();

打开文件：

QString newpath = QFileDialog::getOpenFileName(this, tr("选择 DBC 文件"), path,

                                                   tr("Vector Informatik GmbH database file (*.dbc)"), nullptr,

                                                   QFileDialog::DontResolveSymlinks | QFileDialog::DontUseNativeDialog);

打开文件夹：

    QString pdfCurPath = QFileDialog::getExistingDirectory(

        this, tr("选择文件夹"), LastPath, QFileDialog::DontResolveSymlinks | QFileDialog::DontUseNativeDialog);