QSortFilterProxyModel: How to display all children?

ahsan737

Greetings,
I have introduced filter using QSortFilterProxyModel in combination with QLineEdit. When I search any keyword then it only displays that child which contains the filtered keyword+ parent.

Is there any way that it can display all children (which contain filtered keyword+which do not contain) once a keyword matches a tree?

//------------------------Proxy Model--------------------------
    proxyModel=new QSortFilterProxyModel(this);
    proxyModel->setSourceModel(model);
    proxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
    proxyModel->setDynamicSortFilter(true);
    proxyModel->setFilterKeyColumn(-1);
//--------------------------------------------------------------
void saved_data::on_lineEdit_textChanged(const QString &arg1)
{
    proxyModel->setFilterFixedString(arg1);
    proxyModel->setRecursiveFilteringEnabled(true);
    ui->treeView->expandAll();
}

JonB

@ahsan737
If I understand right: normally setRecursiveFilteringEnabled() will apply filter to all rows (with the additional "and for any matching child, its parents will be visible as well"), while what you want is "if a row matches, then automatically include all its descendants", right?

Since I don't see a setting for this, I imagine you must instead implement bool QSortFilterProxyModel::filterAcceptsRow(int source_row, const QModelIndex &source_parent) const yourself. You would do your own filter pattern matching for the pattern on nodes. Then you can use source_parent to walk up the tree so as to return true when you find a parent is displayed. This would perhaps assume (depending on how you implement it) that row filtering calls are made in parent-first order, but that is probably the case anyway,

ahsan737

@jonb said in QSortFilterProxyModel: How to display all children?:

while what you want is "if a row matches, then automatically include all its descendants", right?

Exactly, I want to display all the descendants once any of child has matched.
Thank you for your detailed reply, I will try to implement it although it sounds a bit complicated to me (as I am a beginner).