Poppler是一个PDF解析和渲染库，可以用于从PDF文件中提取页面和链接。QTreeView是Qt框架中的一个小部件，可用于显示带有树形结构的数据。

要在QTreeView中显示PDF文档的导航菜单，您可以使用以下步骤：

1. 加载PDF文件并获取页面数量。

Poppler::Document *document = Poppler::Document::load("example.pdf");
int pageCount = document->numPages();

1. 创建QTreeView和其模型，并将其设置为窗口的主要小部件。

QTreeView *treeView = new QTreeView(this);
QStandardItemModel *model = new QStandardItemModel();
treeView->setModel(model);
setCentralWidget(treeView);

1. 对于每个页面，获取链接列表并将其添加到模型中。

for (int i = 0; i < pageCount; i++) {
    Poppler::Page *page = document->page(i);
    QList<Poppler::LinkDestination *> links = page->links();

    QStandardItem *pageItem = new QStandardItem(QString("Page %1").arg(i+1));
    model->appendRow(pageItem);

    for (int j = 0; j < links.count(); j++) {
        Poppler::LinkDestination *link = links.at(j);
        QString linkText = link->title().isEmpty() ? QStringLiteral("Link %1").arg(j+1) : link->title();
        QStandardItem *linkItem = new QStandardItem(linkText);
        QVariant destinationVariant = QVariant::fromValue((void *)link->destination());
        linkItem->setData(destinationVariant, Qt::UserRole);
        pageItem->appendRow(linkItem);
    }

    delete page;
}

1. 在QTreeView上设置双击事件处理程序，以便在用户双击链接时打开链接的目标页面。

connect(treeView, &QTreeView::doubleClicked, [=](const QModelIndex &index) {
    QVariant destinationVariant = index.data(Qt::UserRole);
    if (destinationVariant.isValid()) {
        Poppler::Destination *destination = (Poppler::Destination *)destinationVariant.value<void *>();
        int pageNumber = document->page(destination->page())->label().toInt() - 1;
        treeView->selectionModel()->setCurrentIndex(model->index(pageNumber, 0), QItemSelectionModel::ClearAndSelect | QItemSelectionModel::Rows);
    }
});

完整的代码示例：

#include <QApplication>
#include <QStandardItemModel>
#include <QTreeView>
#include <poppler/qt5/poppler-page.h>
#include <poppler/qt5/poppler-link.h>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Poppler::Document *document = Poppler::Document::load("example.pdf");
    int pageCount = document->numPages();

    QTreeView *treeView = new QTreeView();
    QStandardItemModel *model = new QStandardItemModel();
    treeView->setModel(model);
    for (int i = 0; i < pageCount; i++) {
        Poppler::Page *page = document->page(i);
        QList<Poppler::LinkDestination *> links = page->links();

        QStandardItem *pageItem = new QStandardItem(QString("Page %1").arg(i+1));
        model->appendRow(pageItem);

        for (int j = 0; j < links.count(); j++) {
            Poppler::LinkDestination *link = links.at(j);
            QString linkText = link->title().isEmpty() ? QStringLiteral("Link %1").arg(j+1) : link->title();
            QStandardItem *linkItem = new QStandardItem(linkText);
            QVariant destinationVariant = QVariant::fromValue((void *)link->destination());
            linkItem->setData(destinationVariant, Qt::UserRole);
            pageItem->appendRow(linkItem);
        }

        delete page;
    }

    treeView->expandAll();

    QObject::connect(treeView, &QTreeView::doubleClicked, [=](const QModelIndex &index) {
        QVariant destinationVariant = index.data(Qt::UserRole);
        if (destinationVariant.isValid()) {
            Poppler::Destination *destination = (Poppler::Destination *)destinationVariant.value<void *>();
            int pageNumber = document->page(destination->page())->label().toInt() - 1;
            treeView->selectionModel()->setCurrentIndex(model->index(pageNumber, 0), QItemSelectionModel::ClearAndSelect | QItemSelectionModel::Rows);
        }
    });

    treeView->show();

    return a.exec();
}