[SOLVED] QListView remains empty

postb99

Hello,

Please can anyone help. My QListView remains empty, while my model is OK.
If I set a breakpoint in "data()", it doesn't get reached.

Thank you,

@
// standard constructor

// standard destructor

// rowCount is OK
int DicomImageModel::rowCount(const QModelIndex & /parent/) const
{
int i = getImagesCount();
xLogWarning(XLogRecord::Type_User, QString("'rowCount' called, value: %1").arg(i));
return i;
}

// fixed size, do I need to add headers or would it work without?
int DicomImageModel::columnCount(const QModelIndex & /parent/) const
{
return 6;
}

// data... don't log here
QVariant DicomImageModel::data(const QModelIndex &index, int role) const
{
xLogWarning(XLogRecord::Type_User, QString("'data' called"));

 int row = index.row();
 int col = index.column();
 // generate a log message when this method gets called
 xLogWarning(XLogRecord::Type_User, QString("row %1, col%2, role %3").arg(row).arg(col).arg(role));

 //xLogWarning(XLogRecord::Type_User, QString(m_dicomImages[0]->getId()));

 if(role == Qt::DisplayRole){
     if (col == 0) return QString(m_dicomImages[row]->getId());
     //if (col == 1) return QString(m_dicomImages[row]->getDicomRef().getSeriesInstanceUID());

     return QString("Row%1, Column%2")
             .arg(row + 1)
             .arg(col + 1);
 }

 return QString("Row%1, Column%2")
         .arg(row + 1)
         .arg(col + 1);

 return QVariant();

}

// populate model, seems ok but I have no "view" of what happens.
void DicomImageModel::addImage(const XImageObjectPtr image)
{
int nbRows = m_dicomImages.size();
beginInsertRows(QModelIndex(), nbRows, nbRows);
m_dicomImages.push_back(image);
xLogWarning(XLogRecord::Type_User, QString(tr("Image %1 added").arg(image->getId())));
endInsertRows();
}

// just a helper, m_dicomImages is a vector of shared pointers (QSharedPointer).
int DicomImageModel::getImagesCount() const {
return m_dicomImages.size();
}
@

SGaist

Hi,

What is your DicomImageModel for a class ?

Why do you return an empty QVariant for everything that is not DisplayRole ?

postb99

DicomImageModel derive from QAbstractTableModel.

I'm a beginner, so what should I return when it's not a DisplayRole? I lately added this, in fact.

The small plugin I use gets instantiated when I open the main GUI, then if I click on a menu item it gets enabled (visible). It contains a QListView with model previously described.

Something is wrong with rowCount() and columnCount(), they're called at startup, when plugin and model are instantiated, then...

When I add an image to model, rowCount() gets called, but shows "0 row", then I have "1 object in model". It's always 1 item behind.

When I then click onto menu item link, my widget shows, but neither rowCount() nor columnCount() get called again...

SGaist

it should:

@return QAbstractTableModel::data(index, role);@

The row/column count are not constantly queried. Only when you notify the view that the model has changed.

I would recommend that you have a look at the various Model View examples from Qt's documentation. You'll learn how things work with it

postb99

I found the problem: I was reinstantiating the model, since I fixed code but not totally by moving the model declaration to the header. Once fixed I have data as expected.

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[SOLVED] QListView remains empty