Adding a column to QFileSystemModel in a given position

testfilesystemmodeldialog.h
---------------------------------------------------------------------------
#ifndef FILESYSTEMUSBMODELDIALOG_H
#define FILESYSTEMUSBMODELDIALOG_H

#include "ui_testfilesystemmodelwidget.h"

#include <QWidget>
#include <QFileSystemModel>
#include <QItemDelegate>

class QPushButton;

class TestItemFileDelegate : public QItemDelegate
{
public:
  TestItemFileDelegate();
  QSize sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const;
};

class TestFileSystemModel : public QFileSystemModel
{
        Q_OBJECT
public:
    TestFileSystemModel(QObject * parent = 0);
    int columnCount(const QModelIndex& parent = QModelIndex()) const;
    QVariant headerData(int section, Qt::Orientation orientation, int role) const;
    virtual QVariant data ( const QModelIndex & index, int role = Qt::DisplayRole ) const;

public slots:
    void onDirectoryLoaded(const QString & path);
};

class TestFileSystemModelDialog : public QWidget
{
    Q_OBJECT

public:
    explicit TestFileSystemModelDialog(QWidget *parent);
    ~TestFileSystemModelDialog() {}

private:
    Ui::TestFileSystemModelWidget *ui;
    TestFileSystemModel *file;
};

#endif // FILESYSTEMUSBMODELDIALOG_H
---------------------------------------------------------------------------

testfilesystemmodeldialog.cpp
---------------------------------------------------------------------------
#include "testfilesystemmodeldialog.h"

#include <QDebug>
#include <QTimer>
#include <QPushButton>

TestItemFileDelegate::TestItemFileDelegate(){}

static int num = 0;

QSize TestItemFileDelegate::sizeHint ( const QStyleOptionViewItem & /*option*/, const QModelIndex & index ) const
{
    const QFileSystemModel *model = reinterpret_cast<const QFileSystemModel *>(index.model());
    QFileInfo info = model->fileInfo(index);
    if(info.isDir())
    {
        return QSize(40,40);
    }
    else
    {
        return QSize(64,64);
    }
}

TestFileSystemModel::TestFileSystemModel(QObject * parent) :
    QFileSystemModel(parent)
{
    // NOTE: counts before and after the insert both show the same count, and insert returns false.
    int i = QFileSystemModel::columnCount();
    bool b = insertColumn(1);
    int j = QFileSystemModel::columnCount();

    // NOTE: connecting to directoryLoaded() signal to see if deferring the column creation will help.
    bool b1 = connect(this,SIGNAL(directoryLoaded(QString)),this,SLOT(onDirectoryLoaded(QString)));
}

int TestFileSystemModel::columnCount(const QModelIndex& parent) const
{
    return (parent.column() > 0) ? 0 : 5;
}

QVariant TestFileSystemModel::headerData(int section, Qt::Orientation orientation, int role) const
{
  if (section == 4 && orientation == Qt::Horizontal && role == Qt::DisplayRole)
    return tr("File Owner");
  return QFileSystemModel::headerData(section, orientation, role);
}

QVariant TestFileSystemModel::data(const QModelIndex & index, int role) const
{
    if( !index.isValid() )
        return QVariant();
    switch(role)
    {
    case Qt::DisplayRole:
        if (index.column() == 4)
            return QString("Owner %1").arg(num++);
        else
            return QFileSystemModel::data(index, role);
        break;
    case Qt::TextAlignmentRole:
        return Qt::AlignHCenter | Qt::AlignVCenter;
        break;
    default:
        return QFileSystemModel::data(index, role);
        break;
   }
    return QFileSystemModel::data(index, role);
}

void TestFileSystemModel::onDirectoryLoaded(const QString & path)
{
    // NOTE: counts before and after the insert both show the same count, and insert returns false.
    int i = QFileSystemModel::columnCount();
    bool b = insertColumn(1);
    int j = QFileSystemModel::columnCount();
    int o = 0;
}

TestFileSystemModelDialog::TestFileSystemModelDialog(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::TestFileSystemModelWidget)
{
    ui->setupUi(this);

    QString sPath("C:\\tmp");
    file = new TestFileSystemModel();
    QDir fcsDir(sPath);
    file->setFilter(QDir::NoDotAndDotDot | QDir::Files);
    QStringList filters;
    filters << "*.*";
    file->setNameFilters(filters);
    file->setNameFilterDisables(false);
    QModelIndex index = file->setRootPath(fcsDir.absolutePath());

    TestItemFileDelegate *iconItemFileDelegate = new TestItemFileDelegate();

    ui->fileTreeView->setModel(file);
    ui->fileTreeView->setVerticalScrollMode(QAbstractItemView::ScrollPerItem);
    ui->fileTreeView->setItemDelegate(iconItemFileDelegate);
    ui->fileTreeView->setRootIndex(index);
}
---------------------------------------------------------------------------

mainwindow.h
---------------------------------------------------------------------------
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

class TestFileSystemModelDialog;
class QFileSystemModel;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow() {}

private:
    Ui::MainWindow *ui;
    TestFileSystemModelDialog *treeView;
    QFileSystemModel *fileSystemModel;
};

#endif // MAINWINDOW_H

---------------------------------------------------------------------------

mainwindow.cpp
---------------------------------------------------------------------------
#include "mainwindow.h"
#include "testfilesystemmodeldialog.h"

#include <QFileSystemModel>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent)
{
    treeView = new TestFileSystemModelDialog(this);
    setCentralWidget(treeView);
    fileSystemModel = new QFileSystemModel;
}
---------------------------------------------------------------------------

main.cpp
---------------------------------------------------------------------------
#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}
---------------------------------------------------------------------------

testfilesystemmodelwidget.ui
---------------------------------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>TestFileSystemModelWidget</class>
 <widget class="QWidget" name="TestFileSystemModelWidget">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>468</width>
    <height>602</height>
   </rect>
  </property>
  <property name="sizePolicy">
   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
    <horstretch>0</horstretch>
    <verstretch>0</verstretch>
   </sizepolicy>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <layout class="QHBoxLayout" name="horizontalLayout">
   <item>
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
      <widget class="QLabel" name="fileLabel">
       <property name="font">
        <font>
         <pointsize>12</pointsize>
        </font>
       </property>
       <property name="text">
        <string>File to Copy</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QTreeView" name="fileTreeView"/>
     </item>
    </layout>
   </item>
  </layout>
 </widget>
 <resources/>
 <connections/>
</ui>
---------------------------------------------------------------------------