在qt中同时移动滚动条

Question

我编写了以下代码，以便在两个单独的滚动区域中显示一系列图像并同时移动它们。例如，当我相应地移动第一个滚动区域时，第二个滚动区域必须移动并显示相同的图片。不幸的是，代码无法正常工作。我该如何解决这个问题？

MainWindow.cpp

    MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->statusBar->addPermanentWidget(new QLabel(), 1);
    ui->statusBar->addPermanentWidget(statusSelectionRect, 1);
    ui->statusBar->addPermanentWidget(statusMousePos, 1);
    //two connections doesn't work properly
    connect(firstScrollbar, SIGNAL(valueChanged(int)), secondScrollbar, SLOT(setValue(int)));
    connect(secondScrollbar, SIGNAL(valueChanged(int)), firstScrollbar, SLOT(setValue(int)));
    /*************/
    layout = ui->verticalLayout_5;
    layout_2 = ui->verticalLayout_thumbnail;
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_actionOpen_triggered()
{


    QString directory = QFileDialog::getExistingDirectory(this,
                                                          tr("Open Directory"),
                                                          QDir::homePath(),
                                                          QFileDialog::ShowDirsOnly| QFileDialog::DontResolveSymlinks);
    thumbnail(directory);
    int nrows = 1;
    int ncols = 1;
    HorizontalScrollArea *scroll = new HorizontalScrollArea(nrows, ncols);
    layout->addWidget(scroll);
    QDir dir(directory);
    dir.setNameFilters({"*.png", "*.jpg"});
    for(const QFileInfo & finfo: dir.entryInfoList()){
       QListWidgetItem(QIcon(finfo.absoluteFilePath()), finfo.fileName());
        int column = scroll->columnCount();
        for(int row=0; row < nrows; row++){
            QPixmap pic(finfo.absoluteFilePath());
            QImage image(finfo.absoluteFilePath());
            QLabel *label = new QLabel();
            label->setFrameShape(QFrame::WinPanel);
            label->setFrameShadow(QFrame::Raised);
            label->setAlignment(Qt::AlignCenter);
            QScreen *screen = QGuiApplication::primaryScreen();
            QRect  screenGeometry = screen->geometry();
            int height = screenGeometry.height();
            int width = screenGeometry.width();
            label->setPixmap(pic.scaled(width-100,height,Qt::KeepAspectRatio));
            scroll->addWidget(label, row, column);

        }
    }

}

void MainWindow::thumbnail(QString directory)
{
    int nrows = 1;
    int ncols = 1;
    HorizontalScrollArea *scroll_2 = new HorizontalScrollArea(nrows, ncols);
    layout_2->addWidget(scroll_2);
    QDir dir(directory);
    dir.setNameFilters({"*.png", "*.jpg"});
    for(const QFileInfo & finfo: dir.entryInfoList()){
QListWidgetItem(QIcon(finfo.absoluteFilePath()), finfo.fileName());
            int column = scroll_2->columnCount();
            for(int row=0; row < nrows; row++){
                QPixmap pic(finfo.absoluteFilePath());
                QLabel *label_2 = new QLabel(QString("label: %1 %2")
                                           .arg(row)
                                           .arg(column));
                label_2->setAlignment(Qt::AlignCenter);  
             label_2->setPixmap(pic.scaled(ui->frame->maximumWidth(),ui->frame->maximumWidth(),Qt::KeepAspectRatio));
                scroll_2->addWidget(label_2, row, column);
            }
        }
    }

水平滚动区域.h

    class HorizontalScrollArea : public QScrollArea
{
    QWidget *contentWidget;
    QGridLayout *grid;
    int nRows;
    int nColumns;
public:
    HorizontalScrollArea(int rows, int cols, QWidget *parent = Q_NULLPTR)
        :QScrollArea(parent), nRows(rows), nColumns(cols)
    {
        setWidgetResizable(true);
        contentWidget = new QWidget(this);
        setWidget(contentWidget);
        grid = new QGridLayout(contentWidget);
        setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        //setHorizontalScrollBarPolicy( Qt::ScrollBarAlwaysOff );
    }

    void addWidget(QWidget *w, int row, int col){
        grid->addWidget(w, row, col);
        adaptSize();
    }


    int columnCount() const{
        if(grid->count() == 0){
            return 0;
        }
        return grid->columnCount();
    }



private:
    void adaptSize(){
        if(columnCount() >= nColumns ){
            int w = 1.0*(width() - grid->horizontalSpacing()*(nColumns+1.6))/nColumns;
            int wCorrected = w*columnCount() + grid->horizontalSpacing()*(columnCount()+2);
            contentWidget->setFixedWidth(wCorrected);
        }
        contentWidget->setFixedHeight(viewport()->height());
    }
protected:
    void resizeEvent(QResizeEvent *event){
        QScrollArea::resizeEvent(event);
        adaptSize();
    }
};