Check if directory is empty

Question

I'm trying to check if a directory is empty.

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QDir Dir("/home/highlander/Desktop/dir");
    if(Dir.count() == 0)
    {
        QMessageBox::information(this,"Directory is empty","Empty!!!");
    }
}

Whats the right way to check it, excluding . and ..?

`.count()` should return an integer, so compare it to `0`, not `"0"`. — Blender, May 03 '13 at 04:45
well, thats ok, comparing with 1 or 0 is not returning anything whether Dir is empty or not ? — highlander141, May 03 '13 at 04:48

highlander141 · Accepted Answer · 2013-05-03T12:35:19.823

24

Well, I got the way to do it :)

if(QDir("/home/highlander/Desktop/dir").entryInfoList(QDir::NoDotAndDotDot|QDir::AllEntries).count() == 0)
{
    QMessageBox::information(this,"Directory is empty","Empty!!!");
}

edited May 03 '13 at 12:35

answered May 03 '13 at 05:07

highlander141

1,683
3
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2

QDir::AllEntries is not enough for hidden (and possibly system) files. You should check for them as well. – Kirinyale Jul 05 '13 at 12:00

score 5 · Answer 2 · answered May 20 '18 at 15:04

Since Qt 5.9 there is bool QDir::isEmpty(...), which is preferable as it is clearer and faster, see docs:

Equivalent to count() == 0 with filters QDir::AllEntries | QDir::NoDotAndDotDot, but faster as it just checks whether the directory contains at least one entry.

score 2 · Answer 3 · answered Apr 03 '17 at 21:39

As Kirinyale pointed out, hidden and system files (like socket files) are not counted in highlander141's answer. To count these as well, consider the following method:

bool dirIsEmpty(const QDir& _dir)
{
    QFileInfoList infoList = _dir.entryInfoList(QDir::AllEntries | QDir::System | QDir::NoDotAndDotDot | QDir::Hidden );
    return infoList.isEmpty();
}

score 1 · Answer 4 · answered May 03 '13 at 05:05

This is one way of doing it.

#include <QCoreApplication>
#include <QDir>
#include <QDebug>
#include <QDesktopServices>

int main(int argc, char *argv[])
{
    QCoreApplication app(argc,argv);

    QDir dir(QDesktopServices::storageLocation(QDesktopServices::DesktopLocation));

    QStringList list = dir.entryList();
    int count;
    for(int x=0;x<list.count(); x++)
    {
        if(list.at(x) != "." && list.at(x) != "..")
        {
            count++;
        }
    }

    qDebug() << "This directory has " << count << " files in it.";
    return 0;
}

@HeyYO: That seems like a way better solution.. Why not answer and take the credit? — , May 03 '13 at 05:16

score 0 · Answer 5 · answered May 03 '13 at 05:20

0

Or you could just check with;

if(dir.count()<3){
    ... //empty dir
}

answered May 03 '13 at 05:20

HeyYO

1,989
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1

That's another question. This one is the simplest solution to the question you asked. – May 03 '13 at 05:43
3

Magic numbers is very bad practice. It may be different on other platforms. – Dmitry Sazonov May 03 '13 at 09:42

Check if directory is empty

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