前言

本文分享QT开发PDF阅读器技术，希望对各位小伙伴有所帮助！

感谢各位小伙伴的点赞+关注，小易会继续努力分享，一起进步！

你的点赞就是我的动力(＾Ｕ＾)ノ~ＹＯ

结果展示：

我将收获到的：

1. 如何创建PDFViewer

2.创建PDFViewer所依赖的QT库

3.PDFViewer的用处

前言

1.准备PDFViewer所依赖的库

2.创建PDF Viewer

小结：

1.准备PDFViewer所依赖的库

》使用开发的QT版本：5.15.2

》存在问题：不能直接添加PDF模块

》原因：QT5.15.2版本已带有pdf模块，但并未在include中包含，但是在lib和bin目录下能找到相应的.lib和.dll文件。

》解决方案：

》下载QT5.15.2源码

》将“Qt\5.15.2\Src\qtwebengine\include”文件夹下的QtPdf和QtPdfWidgets复制到“Qt\5.15.2\msvc2019_64\include”文件夹下。

》将“Qt\5.15.2\Src\qtwebengine\src\pdf\api”文件夹下的.h文件复制到“Qt\5.15.2\msvc2019_64\include\QtPdf”文件夹下。

》将“Qt\5.15.2\Src\qtwebengine\src\pdfwidgets”文件夹下的.h文件复制到“Qt\5.15.2\msvc2019_64\include\QtPdfWidgets”文件夹下

》我已将QtPdf整理成单独的依赖库，需要的小伙伴可以联系我下载。

也上传CSDN，下载地址：QT开发PDF阅读器，代码简洁易用！资源-CSDN文库

2.创建PDF Viewer

》创建UI文件

》核心为PageSelector(页面选择)和ZoomSelector（缩放）

》下载地址：QT开发PDF阅读器，代码简洁易用！资源-CSDN文库

》代码如下：

PageSelector.h文件

#ifndef PAGESELECTOR_H
#define PAGESELECTOR_H

#include <QWidget>

class QLabel;
class QLineEdit;
class QPdfDocument;
class QPdfPageNavigation;
class QToolButton;

class PageSelector : public QWidget
{
    Q_OBJECT

public:
    explicit PageSelector(QWidget *parent = nullptr);

    void setPageNavigation(QPdfPageNavigation *pageNavigation);

private slots:
    void onCurrentPageChanged(int page);
    void pageNumberEdited();

private:
    QPdfPageNavigation *m_pageNavigation;

    QLineEdit *m_pageNumberEdit;
    QLabel *m_pageCountLabel;
    QToolButton *m_previousPageButton;
    QToolButton *m_nextPageButton;
};

#endif // PAGESELECTOR_H

PageSelector.cpp文件

#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));
}

ZoomSelector.h文件

#ifndef ZOOMSELECTOR_H
#define ZOOMSELECTOR_H

#include <QComboBox>
#include <QPdfView>

class ZoomSelector : public QComboBox
{
    Q_OBJECT

public:
    explicit ZoomSelector(QWidget *parent = nullptr);

public slots:
    void setZoomFactor(qreal zoomFactor);

    void reset();

signals:
    void zoomModeChanged(QPdfView::ZoomMode zoomMode);
    void zoomFactorChanged(qreal zoomFactor);

private slots:
    void onCurrentTextChanged(const QString &text);
};

#endif // ZOOMSELECTOR_H

ZoomSelector.cpp文件

#include "zoomselector.h"

#include <QLineEdit>

ZoomSelector::ZoomSelector(QWidget* parent)
    : QComboBox(parent)
{
    setEditable(true);

    addItem(QLatin1String("Fit Width"));
    addItem(QLatin1String("Fit Page"));
    addItem(QLatin1String("12%"));
    addItem(QLatin1String("25%"));
    addItem(QLatin1String("33%"));
    addItem(QLatin1String("50%"));
    addItem(QLatin1String("66%"));
    addItem(QLatin1String("75%"));
    addItem(QLatin1String("100%"));
    addItem(QLatin1String("125%"));
    addItem(QLatin1String("150%"));
    addItem(QLatin1String("200%"));
    addItem(QLatin1String("400%"));

    connect(this, static_cast<void(QComboBox::*)(const QString&)>(&QComboBox::currentIndexChanged),
        this, &ZoomSelector::onCurrentTextChanged);

    connect(lineEdit(), &QLineEdit::editingFinished,
        this, [this]() {onCurrentTextChanged(lineEdit()->text()); });
}

void ZoomSelector::setZoomFactor(qreal zoomFactor)
{
    setCurrentText(QString::number(qRound(zoomFactor * 100)) + QLatin1String("%"));
}

void ZoomSelector::reset()
{
    setCurrentIndex(8); // 100%
}

void ZoomSelector::onCurrentTextChanged(const QString& text)
{
    if (text == QLatin1String("Fit Width")) {
        emit zoomModeChanged(QPdfView::FitToWidth);
    }
    else if (text == QLatin1String("Fit Page")) {
        emit zoomModeChanged(QPdfView::FitInView);
    }
    else {
        qreal factor = 1.0;

        QString withoutPercent(text);
        withoutPercent.remove(QLatin1Char('%'));

        bool ok = false;
        const int zoomLevel = withoutPercent.toInt(&ok);
        if (ok)
            factor = zoomLevel / 100.0;

        emit zoomModeChanged(QPdfView::CustomZoom);
        emit zoomFactorChanged(factor);
    }
}