PDF Viewer Example

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 #include "pageselector.h"

 #include <QHBoxLayout>
 #include <QLabel>
 #include <QLineEdit>
 #include <QPdfPageNavigation>
 #include <QToolButton>

 PageSelector::PageSelector(QWidget *parent)
     : QWidget(parent)
     , m_pageNavigation(nullptr)
 {
     QHBoxLayout *layout = new QHBoxLayout(this);

     m_previousPageButton = new QToolButton(this);
     m_previousPageButton->setText("<");
     m_previousPageButton->setEnabled(false);

     m_pageNumberEdit = new QLineEdit(this);
     m_pageNumberEdit->setAlignment(Qt::AlignRight);

     m_pageCountLabel = new QLabel(this);
     m_pageCountLabel->setText("0");

     m_nextPageButton = new QToolButton(this);
     m_nextPageButton->setText(">");
     m_nextPageButton->setEnabled(false);

     layout->addWidget(m_previousPageButton);
     layout->addWidget(m_pageNumberEdit);
     layout->addWidget(m_pageCountLabel);
     layout->addWidget(m_nextPageButton);
 }

 void PageSelector::setPageNavigation(QPdfPageNavigation *pageNavigation)
 {
     m_pageNavigation = pageNavigation;

     connect(m_previousPageButton, &QToolButton::clicked, m_pageNavigation, &QPdfPageNavigation::goToPreviousPage);
     connect(m_pageNavigation, &QPdfPageNavigation::canGoToPreviousPageChanged, m_previousPageButton, &QToolButton::setEnabled);

     connect(m_pageNavigation, &QPdfPageNavigation::currentPageChanged, this, &PageSelector::onCurrentPageChanged);
     connect(m_pageNavigation, &QPdfPageNavigation::pageCountChanged, this, [this](int pageCount){ m_pageCountLabel->setText(QString::fromLatin1("/ %1").arg(pageCount)); });

     connect(m_pageNumberEdit, &QLineEdit::editingFinished, this, &PageSelector::pageNumberEdited);

     connect(m_nextPageButton, &QToolButton::clicked, m_pageNavigation, &QPdfPageNavigation::goToNextPage);
     connect(m_pageNavigation, &QPdfPageNavigation::canGoToNextPageChanged, m_nextPageButton, &QToolButton::setEnabled);

     onCurrentPageChanged(m_pageNavigation->currentPage());
 }

 void PageSelector::onCurrentPageChanged(int page)
 {
     if (m_pageNavigation->pageCount() == 0)
         m_pageNumberEdit->setText(QString::number(0));
     else
         m_pageNumberEdit->setText(QString::number(page + 1));
 }

 void PageSelector::pageNumberEdited()
 {
     if (!m_pageNavigation)
         return;

     const QString text = m_pageNumberEdit->text();

     bool ok = false;
     const int pageNumber = text.toInt(&ok);

     if (!ok)
         onCurrentPageChanged(m_pageNavigation->currentPage());
     else
         m_pageNavigation->setCurrentPage(qBound(0, pageNumber - 1, m_pageNavigation->pageCount() - 1));
 }