QPushButton in QTableView - c++

Question

I'm working on a project where i'm trying to add a QPushButton into a QTableView.
also i want to connect that button to open a document from a database. So far i added the button and i wrote the connect statement for it but when i click on the button nothing happened.
here is my code
void MainWindow::DocumentTable()
{
tableview = new QTableView;
query = new QSqlQueryModel(this);
signalMapper = new QSignalMapper(this);
foreach(it,treeWidget->selectedItems())
{
for (int col=0; col< it->columnCount(); ++col)
{
qDebug() << col << it->text(col);
QSqlQuery qry;
qry.prepare("select * from document where Folno=:Folno");
qry.bindValue(":Folno", it->text(col));
qry.exec();
query->setQuery(qry);
tableview->setModel(query);
tableview->setEditTriggers(QAbstractItemView::NoEditTriggers);
for (int i = 0; i< 1000; i++)
{
button= new QPushButton("Open Document");
tableview->setIndexWidget(tableview->model()->index(i, 0), button);
signalMapper->setMapping(button, i);
}
connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(imageFROMdatabase()));
tableview->show();
Docwidget= new QDockWidget(this);
Docwidget->setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
Docwidget->setWidget(tableview);
addDockWidget(Qt::RightDockWidgetArea,Docwidget);
Docwidget->show();
if(!query->submit())
{
QMessageBox::warning(0,"Error",query->lastError().text());
}
db.close();
}
}
}
and this is the slot function
void MainWindow::imageFROMdatabase()
{
QSqlQuery imageQuery;
imageQuery.prepare("SELECT * from doc_page where doc_no=:doc_no and f_number=:f_number");
imageQuery.bindValue(":doc_no", 1);
imageQuery.bindValue(":f_number",1);
imageQuery.exec();
imageQuery.next();
if( imageQuery.lastError().isValid())
{
QMessageBox::warning(0,"Error",imageQuery.lastError().text());
// QSqlDatabase::database().rollback();
}
else
{
// QByteArray ba1 = imageQuery.value(1).toByteArray();
QPixmap pic;
pic.loadFromData( ba);
scrollArea = new QScrollArea;
scrollArea->setBackgroundRole(QPalette::Dark);
scrollArea->setEnabled(true);
QString fileName = QFileDialog::getOpenFileName(this,"Open Image File",QDir::currentPath());
QImage image(fileName);
scene = new QGraphicsScene();
view = new QGraphicsView(scene);
item = new QGraphicsPixmapItem(QPixmap::fromImage(image));
scene->addItem(item);
xwidget= new QDockWidget(this);
xwidget->setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
xwidget->setWidget(view);
addDockWidget(Qt::RightDockWidgetArea,xwidget);
xwidget->show();
db.close();
}
}
please tell if anything wrong in these codes.

Answer 1

The slot method is not same as signal method. They should have exact equal signatures. qDebug() should have generated some warnings for you. Read outputs carefully. imageFROMDatabase() method should accept an integer as its input too. Signals are not real functions. They are used to trigger another function which is matched in signature with them.
connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(imageFROMdatabase()));
Change it like this :
connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(imageFROMdatabase(int)));
ans also :
void MainWindow::imageFROMdatabase( int x ) { ... }
Also if the signals and slots are not in a thread read the manual enum Qt::ConnectionType