How to wait for QFileSystemModel so that rowCount() != 0

yafes

Hi,

From the Documentation:
Unlike QDirModel, QFileSystemModel uses a separate thread to populate itself so it will not cause the main thread to hang as the file system is being queried. Calls to rowCount() will return 0 until the model populates a directory.

Question
What is the right way to wait for QFileSystemModel to finish it's procedure?

@ QFileSystemModel *fileModel;
QModelIndex parentIndex = fileModel->index(path);
int numRows = fileModel->rowCount(parentIndex);@

SGaist

Hi,

The "directoryLoaded":http://doc.qt.io/qt-5/qfilesystemmodel.html#directoryLoaded signal might be a good starting point

Hope it helps

yafes

Hi SGaist,

i think i am accessing the signal in a wrong way,

In Widget.cpp:

@
dirModel = new MyQFileSystemModel;
connect(dirModel, SIGNAL(directoryLoaded(const QString &)), this, SLOT(toggled(const QString&)));@

in Widget.h:
@signals:
void directoryLoaded(const QString &path);

public slots:
void toggled(const QString &path);@

Am i doing something wrong?
Error: No such signal QFileSystemModel::?directoryLoaded(const QString &)

SGaist

Yes you do, your SIGNAL and SLOT statements are wrong.

@
connect(dirModel, SIGNAL(directoryLoaded(QString)), this, SLOT(toggled(QString)));
@

Out of curiosity, why the directoryLoaded in Widget.h ?

yafes

Hi SGaist, still does not work
QObject::connect: No such signal QFileSystemModel::?directoryLoaded(QString) in ..\AssetBrowser_02\widget.cpp:126

Out of curiosity, why the directoryLoaded in Widget.h ?

Do you mean in terms of Programm-Design? I am prototyping in widget.cpp and encapsulating it later in the appropriate classes.

SGaist

Looks like you implement a custom MyQFileSystemModel, how does it look like ?

Can you show again your connect statement ?

yafes

SGaist,

i just have overwritten the data in my custom MyQFileSystemModel:
@class MyQFileSystemModel : public QFileSystemModel {
public:
QVariant data( const QModelIndex& index, int role ) const {

    if( role == Qt::DecorationRole ) {
        return QVariant(QIcon(QPixmap(":/myresources/images/folder-icon.png")));
    }

    return QFileSystemModel::data(index, role);
}

};@

My Connect Statement:
@connect(dirModel, SIGNAL(directoryLoaded(QString)), this, SLOT(toggled(QString)));@

SGaist

You can also use a QIdentityProxyModel for such customization. That allows to reuse the same QFileSystemModel with several views (if you need such a thing)

What version of Qt are you using ?

andre

I think SGaist's solution is the better one. Furtheremore, your subclass is not complete: no Q_OBJECT macro, no constructor, etc.

yafes

I am using version 5.4. The constructor should be derived from the base-class. Can the macro be derived as well? I don't know whats happening deep inside QT.

Ok now with the proxy model i get a runtime debug message:
QAbstractItemView::setRootIndex failed : index must be from the currently set model

I was setting the root Index like this:
ui->treeView->setRootIndex(dirModel->setRootPath(Globals::filePath));

I don't know if the error is coming from this part of the code, but seems to be, as i am only setting the root Index here. So how can i set now the index? The Proxy Model has no methods for that.

Thanks in advance