QPainter::begin(): Returned false - qt

Question

So i'm using QT 5.15.2 and what i'm trying to do here is print ot PDF the content of a QTableView into a PDF File here's my code
void ManageTeachers::on_print_clicked() {
QPdfWriter pdf("C:");
QPainter painter(&pdf);
int i = 4000;
painter.setPen(Qt::blue);
painter.setFont(QFont("Arial", 30));
painter.drawText(1100,1200,"List of teachers");
painter.setPen(Qt::black);
painter.setFont(QFont("Arial", 15));
painter.drawRect(100,100,7300,2600);
painter.drawRect(0,3000,9600,500);
painter.setFont(QFont("Arial", 9));
painter.drawText(200,3300,"CIN");
painter.drawText(1300,3300,"First name");
painter.drawText(2100,3300,"last name");
painter.drawText(3200,3300,"phone");
painter.drawText(5300,3300,"email");
painter.drawText(5300,3300,"salary");
QSqlQuery query;
query.prepare("select * from teacher");
query.exec();
while (query.next())
{
painter.drawText(200,i,query.value(0).toString());
painter.drawText(1300,i,query.value(1).toString());
painter.drawText(2200,i,query.value(2).toString());
painter.drawText(3200,i,query.value(3).toString());
painter.drawText(4500,i,query.value(4).toString());
i = i + 500;
}
int reponse = QMessageBox::question(this, "Génerer PDF", "<PDF Enregistré>...Vous Voulez Affichez Le PDF ?", QMessageBox::Yes | QMessageBox::No);
if (reponse == QMessageBox::Yes)
{
painter.end();
}
if (reponse == QMessageBox::No)
{
painter.end();
} }
The problem is that in the console i get these errors
QPainter::begin(): Returned false
QPainter::setPen: Painter not active
QPainter::setFont: Painter not active
QPainter::setPen: Painter not active
QPainter::setFont: Painter not active
QPainter::drawRects: Painter not active
QPainter::drawRects: Painter not active
QPainter::setFont: Painter not active
QPainter::end: Painter not active, aborted
Any help ? i added the QT+= printsupport multimedia

Answer 1

QPdfWriter pdf("C:");
QPainter painter(&pdf);
This is very suspect. If you consult the documentation for QPdfWriter it notes that the first parameter should be a filename. "C:" is not a filename. You need to pass the name of the file you want to write to, something like:
QString filename("C:/my_file.pdf");
QPdfWriter pdf(filename);
QPainter painter(&pdf);