【Qt5】 Qt 中对于文件全名、基本名、路径、扩展名的获取

一、简介:

在Qt 中有时需要从文件名串中分别获取路径、文件全名、扩展名，这时就需要使用  QFileInfo。

二、示例代码：

#include <QFileInfo>
...

    QString filename = QFileDialog::getOpenFileName(this, QStringLiteral("打开文件"), "",
                                                    QStringLiteral("图像文件(*.jpg;*.jpeg;*.bmp;*.png);;所有文件(*.*)"));
    if (filename.isEmpty())  return 1;

    QFileInfo fileInfo(filename);
    qDebug() << QStringLiteral("文件所在路径: ") << fileInfo.path();
    qDebug() << QStringLiteral("文件及路径: ") << fileInfo.filePath();
    qDebug() << QStringLiteral("文件全名: ") << fileInfo.fileName();
    qDebug() << QStringLiteral("文件基本名: ") << fileInfo.baseName();
    qDebug() << QStringLiteral("扩展名: ") << fileInfo.suffix();

三、QFileInfo 的定义：

在 QFileInfo类中，还可以取得有关文件的更多信息。（类定义在 qfileinfo.h 头文件中）

class Q_CORE_EXPORT QFileInfo
{
    friend class QDirIteratorPrivate;
public:
    explicit QFileInfo(QFileInfoPrivate *d);

    QFileInfo();
    QFileInfo(const QString &file);
    QFileInfo(const QFile &file);
    QFileInfo(const QDir &dir, const QString &file);
    QFileInfo(const QFileInfo &fileinfo);
    ~QFileInfo();

    QFileInfo &operator=(const QFileInfo &fileinfo);
#ifdef Q_COMPILER_RVALUE_REFS
    QFileInfo &operator=(QFileInfo &&other) Q_DECL_NOTHROW { swap(other); return *this; }
#endif

    void swap(QFileInfo &other) Q_DECL_NOTHROW
    { qSwap(d_ptr, other.d_ptr); }

    bool operator==(const QFileInfo &fileinfo) const;
    inline bool operator!=(const QFileInfo &fileinfo) const { return !(operator==(fileinfo)); }

    void setFile(const QString &file);
    void setFile(const QFile &file);
    void setFile(const QDir &dir, const QString &file);
    bool exists() const;
    static bool exists(const QString &file);
    void refresh();

    QString filePath() const;
    QString absoluteFilePath() const;
    QString canonicalFilePath() const;
    QString fileName() const;
    QString baseName() const;
    QString completeBaseName() const;
    QString suffix() const;
    QString bundleName() const;
    QString completeSuffix() const;

    QString path() const;
    QString absolutePath() const;
    QString canonicalPath() const;
    QDir dir() const;
    QDir absoluteDir() const;

    bool isReadable() const;
    bool isWritable() const;
    bool isExecutable() const;
    bool isHidden() const;
    bool isNativePath() const;

    bool isRelative() const;
    inline bool isAbsolute() const { return !isRelative(); }
    bool makeAbsolute();

    bool isFile() const;
    bool isDir() const;
    bool isSymLink() const;
    bool isRoot() const;
    bool isBundle() const;

    QString readLink() const;
    inline QString symLinkTarget() const { return readLink(); }

    QString owner() const;
    uint ownerId() const;
    QString group() const;
    uint groupId() const;

    bool permission(QFile::Permissions permissions) const;
    QFile::Permissions permissions() const;

    qint64 size() const;

    // ### Qt6: inline these functions
#if QT_DEPRECATED_SINCE(5, 10)
    QT_DEPRECATED_X("Use either birthTime() or metadataChangeTime()")
    QDateTime created() const;
#endif
    QDateTime birthTime() const;
    QDateTime metadataChangeTime() const;
    QDateTime lastModified() const;
    QDateTime lastRead() const;
    QDateTime fileTime(QFile::FileTime time) const;

    bool caching() const;
    void setCaching(bool on);

protected:
    QSharedDataPointer<QFileInfoPrivate> d_ptr;

private:
    QFileInfoPrivate* d_func();
    inline const QFileInfoPrivate* d_func() const
    {
        return d_ptr.constData();
    }
};

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