QDirIterator Class

Detailed Description

You can use QDirIterator to navigate entries of a directory one at a time. It is similar to QDir::entryList() and QDir::entryInfoList(), but because it lists entries one at a time instead of all at once, it scales better and is more suitable for large directories. It also supports listing directory contents recursively, and following symbolic links. Unlike QDir::entryList(), QDirIterator does not support sorting.

The QDirIterator constructor takes a QDir or a directory as argument. After construction, the iterator is located before the first directory entry. Here's how to iterate over all the entries sequentially:

 QDirIterator it("/etc", QDirIterator::Subdirectories);
 while (it.hasNext()) {
     QString dir = it.next();
     qDebug() << dir;
     // /etc/.
     // /etc/..
     // /etc/X11
     // /etc/X11/fs
     // ...
 }

Here's how to find and read all files filtered by name, recursively:

 QDirIterator it("/sys", QStringList() << "scaling_cur_freq", QDir::NoFilter, QDirIterator::Subdirectories);
 while (it.hasNext()) {
     QFile f(it.next());
     f.open(QIODevice::ReadOnly);
     qDebug() << f.fileName() << f.readAll().trimmed().toDouble() / 1000 << "MHz";
 }

The next() function returns the path to the next directory entry and advances the iterator. You can also call filePath() to get the current file path without advancing the iterator. The fileName() function returns only the name of the file, similar to how QDir::entryList() works. You can also call fileInfo() to get a QFileInfo for the current entry.

Unlike Qt's container iterators, QDirIterator is uni-directional (i.e., you cannot iterate directories in reverse order) and does not allow random access.