How To Install Custom Icon in QFileDialog

[kendavistoo]

In order to make my project folders distinguishable I have added a ".PjtsZr" suffix to their name. When I call QFileDialog to select one of these folders, I want them to have a different folder icon within the dialog. I use the following to use the QFileDialog:

    QFileDialog dialog(this,  "Select Project Directory", "~/");
    dialog.setFileMode(QFileDialog::DirectoryOnly);
    dialog.setOption(QFileDialog::DontUseNativeDialog, true);
    dialog.setWindowFlags(Qt::Dialog);
    dialog.setViewMode(QFileDialog::List);

    QString dirPath;

    if (dialog.exec() == QDialog::Accepted) {
        dirPath = dialog.selectedFiles().value(0);
    }

    QDir dir(dirPath);

It has been suggested on the internet to use the QSortFilterProxyModel Class to see the items of the QFileDialog, and this seems to work. But, once I detect a directory with the ".PjtsZr" extension, how do I change its icon?

//---------- filterAcceptsRow ----------

bool PjtFileFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
{
    QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
    QFileSystemModel* fileModel = qobject_cast<QFileSystemModel*>(sourceModel());

    QString p = QDir::homePath();
    QString homeName = gLastNameOfPath(p);

    //----------

    if (fileModel!=NULL && fileModel->isDir(index0))
    {
        QString modelStr = fileModel->fileName(index0);

        if (modelStr.compare(homeName) == 0){
            qDebug() << "HELLO PROXY   home:    "<<modelStr;
            return true;
        }//if

        //----------

        if (modelStr.endsWith("PjtsZr")){

            qDebug()<<"GOT ONE!!!     "<<fileModel->filePath(index0);

            QString pjtDirPath = fileModel->filePath(index0);
            QDir pjtDir(pjtDirPath);

            return true;
        }//if

        return true;
    }//if

    else{
        return false;
    }//else

    // uncomment below to execute default implementation
    //return QSortFilterProxyModel::filterAcceptsRow(sourceRow, sourceParent);
}

[Christian Ehrlicher]

You can set your proxy model with http://doc.qt.io/qt-5/qfiledialog.html#setProxyModel

[kendavistoo]

Thanks, Christian Ehrlicher, your suggestion was essential.

I finally solved the problem. Notice that globals.h contains all of the nic-nak Qt "#include"'s necessary to make it work.

pjticonprovider.h:

#ifndef GLOBALS_H
#include "globals.h"
#endif

const static int    PV_FILE_FOLDER   = 0;
const static int    PV_PINK_FOLDER   = 1;
const static int    PV_OOPS          = 2;

class PjtIconProvider : public QFileIconProvider
{
public:
    PjtIconProvider();
    ~PjtIconProvider();

    //QIcon icon( const QFileInfo & info ) const;

    QIcon icon(const QFileInfo & info) const;

private:
    QIcon pinkFolder;
    QIcon defaultFolder;
    QIcon oopsIcon;
};

pjticonprovider.cpp:

#include "pjticonprovider.h"

//---------- CONSTRUCTOR PjtIconProvider -----------
PjtIconProvider :: PjtIconProvider()
{
    qDebug()<<"CONSTRUCTOR PjtIconProvider";

    defaultFolder = QIcon(":/Icons/FolderIcon.svg");
    pinkFolder    = QIcon(":/Icons/PinkIcon.png");
    oopsIcon      = QIcon(":/Icons/OopsIcon.png");
}
//---------- DESTRUCTOR ~PjtIconProvider -----------
PjtIconProvider :: ~PjtIconProvider()
{
    qDebug()<<"DESTRUCTOR PjtIconProvider";
}
//---------- icon -----------
QIcon PjtIconProvider :: icon( const QFileInfo & info) const
{
    QString name = info.fileName();

    if (name.endsWith("PjtsZr")){
        return pinkFolder;
    }//if

    else if(( ! name.isEmpty()) and ( ! name.isNull())){
        return defaultFolder;
    }//elseif

    return oopsIcon;

pjtfilefilterproxymodel.h:

#ifndef PJTICONPROVIDER_H
#include "pjticonprovider.h"
#endif

#ifndef GLOBALS_H
#include "globals.h"
#endif

class PjtFileFilterProxyModel : public QSortFilterProxyModel
{
    Q_OBJECT
public:
    PjtFileFilterProxyModel();
    ~PjtFileFilterProxyModel();

    PjtIconProvider *provider;
protected:
    virtual bool filterAcceptsRow(int source_row, const QModelIndex& source_parent) const;
};

pjtfilefilterproxymodel.cpp:

#include "pjtfilefilterproxymodel.h"

//---------- CONSTRUCTOR PjtFileFilterProxyModel ----------
PjtFileFilterProxyModel :: PjtFileFilterProxyModel()
{
    qDebug()<<"CONSTRUCTOR PjtFileFilterProxyModel";

    provider = new PjtIconProvider();
}

//---------- DESTRUCTOR PjtFileFilterProxyModel ----------
PjtFileFilterProxyModel :: ~PjtFileFilterProxyModel()
{
    qDebug()<<"DESTRUCTOR PjtFileFilterProxyModel";

    delete provider;
}

//---------- filterAcceptsRow ----------
bool PjtFileFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
{
    QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
    QFileSystemModel* fileModel = qobject_cast<QFileSystemModel*>(sourceModel());

    fileModel->setIconProvider(provider);

QFileInfo info = fileModel->fileInfo(index0);
qDebug()<<info.fileName();

    return true;

    // uncomment below to execute default implementation
    //return QSortFilterProxyModel::filterAcceptsRow(sourceRow, sourceParent);
}

Notice that the UI of the QFileDialog still is awkward, but will be fixed soon. Here is the slot within MainWindow which handles the dialog:

//---------- SLOT openProject ----------
void MainWindow :: SlotOpenProject()
{
    qDebug()<<"    openProject";

    statusMessageKey = S_OPEN_A_PROJECT;
    doFreshStatusMessage = true;

    QString     dirPath;

    QFileDialog dialog(this, "Select Project Directory", "/home" );
    dialog.setNameFilter("*/PjtsZr");
    dialog.setOption( QFileDialog::DontUseNativeDialog );
    dialog.setOption( QFileDialog::ShowDirsOnly );
    dialog.setOption( QFileDialog::DontResolveSymlinks );

    PjtFileFilterProxyModel* proxyModel = new PjtFileFilterProxyModel();
    dialog.setProxyModel(proxyModel);

    QDialogButtonBox *button_box = findChild<QDialogButtonBox *>();
    button_box->addButton("Select", QDialogButtonBox::AcceptRole);

    dialog.exec();

    QStringList sList = dialog.selectedFiles();
    QString selectedPjt( sList.at(0) );

qDebug()<<"<<<<<<<<<<<<<<<<<<<<<<<<<<<      selected:  "<<selectedPjt;

}//openProject