QTreeView and QStandardModel : add children

[Valheru]

I have a QTreeView subclassed, and it has a QStandardModel so as to be able to provide headers. I add items to the model from a database, namely servers and the connections to them. There are multiple connections to every server, with a default of 4. The code I have adds the connections under the servers, with no indentation and no arrow or + sign to collapse the servers and make the connections invisible. I assume that I'm adding the connections wrong and they are not being added as children.

ServerList::ServerList( QWidget *p)
{
  parent = p;
  model = new QStandardItemModel( 0, 1 );
  model->setHeaderData( 0, Qt::Horizontal, "Server List" );
  setModel( model );
  setSelectionMode( QAbstractItemView::SingleSelection );
  ///Set up the actions for the right-click context menu
  connectToServer = new QAction(tr("Connect"), this);
  separator = new QAction(this);
  separator->setSeparator(true);
  newServer = new QAction(tr("New Server"), this);
  editServer = new QAction(tr("Edit Server"), this);
  deleteServer = new QAction(tr("Delete Server"), this);
  ///Set up the menu
  menu = new QMenu();
  menu->addAction(connectToServer);
  menu->addAction(separator);
  menu->addAction(newServer);
  menu->addAction(editServer);
  menu->addAction(deleteServer);
  ///Connect the actions
  connect( connectToServer, SIGNAL( triggered() ), this, SLOT( connectToServerSlot() ) );
  connect( newServer, SIGNAL( triggered() ), this, SLOT( newServerSlot() ) );
  connect( editServer, SIGNAL( triggered() ), this, SLOT( editServerSlot() ) );
  connect( deleteServer, SIGNAL( triggered() ), this, SLOT( deleteServerSlot() ) );
}

ServerList::ServerList( QWidget *p)
{
  parent = p;
  model = new QStandardItemModel( 0, 1 );
  model->setHeaderData( 0, Qt::Horizontal, "Server List" );
  setModel( model );
  setSelectionMode( QAbstractItemView::SingleSelection );
  ///Set up the actions for the right-click context menu
  connectToServer = new QAction(tr("Connect"), this);
  separator = new QAction(this);
  separator->setSeparator(true);
  newServer = new QAction(tr("New Server"), this);
  editServer = new QAction(tr("Edit Server"), this);
  deleteServer = new QAction(tr("Delete Server"), this);
  ///Set up the menu
  menu = new QMenu();
  menu->addAction(connectToServer);
  menu->addAction(separator);
  menu->addAction(newServer);
  menu->addAction(editServer);
  menu->addAction(deleteServer);
  ///Connect the actions
  connect( connectToServer, SIGNAL( triggered() ), this, SLOT( connectToServerSlot() ) );
  connect( newServer, SIGNAL( triggered() ), this, SLOT( newServerSlot() ) );
  connect( editServer, SIGNAL( triggered() ), this, SLOT( editServerSlot() ) );
  connect( deleteServer, SIGNAL( triggered() ), this, SLOT( deleteServerSlot() ) );
}

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void ServerList::addItem( const QString &hostName, quint16 port, const QString& username,
                          const QString& password, quint16 timeout, quint16 numberConnections )
{
  QModelIndex parent = model->index( 0, 0, parent );
  int rows = model->rowCount( parent );
  model->insertRows( rows, 1, parent );
  QModelIndex index = model->index( rows, 0, parent );
  model->setData( index, hostName );
  Server ns( hostName, port, username, password, timeout, numberConnections );
  server.append( ns );
  for( int x = 0; x < numberConnections; x++ ){
    QModelIndex parentServer = model->index( rows, 0, index );
    int serverRow = model->rowCount( parentServer );
    model->insertRows( serverRow, 1, parentServer );
    QModelIndex connectionIndex = model->index( serverRow, 0, parentServer );
    QString s("Connection #");
    s += QString::number( x + 1 );
    model->setData( connectionIndex, s );
  }
}

void ServerList::addItem( const QString &hostName, quint16 port, const QString& username,
                          const QString& password, quint16 timeout, quint16 numberConnections )
{
  QModelIndex parent = model->index( 0, 0, parent );
  int rows = model->rowCount( parent );
  model->insertRows( rows, 1, parent );
  QModelIndex index = model->index( rows, 0, parent );
  model->setData( index, hostName );
  Server ns( hostName, port, username, password, timeout, numberConnections );
  server.append( ns );
  for( int x = 0; x < numberConnections; x++ ){
    QModelIndex parentServer = model->index( rows, 0, index );
    int serverRow = model->rowCount( parentServer );
    model->insertRows( serverRow, 1, parentServer );
    QModelIndex connectionIndex = model->index( serverRow, 0, parentServer );
    QString s("Connection #");
    s += QString::number( x + 1 );
    model->setData( connectionIndex, s );
  }
}

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[wysota]

What are 'parent' and 'parentServer' initialised to?

[Valheru]

Erm, they're not :/ What you see is what you get, in this case

[wysota]

How do you expect to use them if they are not initialised?

[Valheru]

What should I initialize them to then? I´m sorry, but I´m new to the model/view way of doing this and am just happy that it´s working at all The docs themselves are rather vague on this subject as well I find

[wysota]

What should I initialize them to then?

I don't know. It is you who used them. Didn't you know what you needed them for?

The docs themselves are rather vague on this subject as well I find

Hmm.... Maybe you didn't look well enough...

An example usage of QStandardItemModel to create a tree:

QStandardItemModel *model = new QStandardItemModel();
QModelIndex parent;
for (int i = 0; i < 4; ++i) {
    parent = model->index(0, 0, parent);
    model->insertRows(0, 1, parent);
    model->insertColumns(0, 1, parent);
    QModelIndex index = model->index(0, 0, parent);
    model->setData(index, i);
}

QStandardItemModel *model = new QStandardItemModel();
QModelIndex parent;
for (int i = 0; i < 4; ++i) {
    parent = model->index(0, 0, parent);
    model->insertRows(0, 1, parent);
    model->insertColumns(0, 1, parent);
    QModelIndex index = model->index(0, 0, parent);
    model->setData(index, i);
}

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It creates a cascade of 4 elements. If you want to have a two level tree you should modify the code a little, so that the parent index doesn't get changed at each iteration:

QStandardItemModel *model = new QStandardItemModel();
int parentrow = 2; // top level row number you wish to create offsprings for
QStringList connectionData;
connectionData << "Con1" << "Con2" << "Con3" << "Con4";
QModelIndex parent = model->index(parentrow, 0);
model->insertColumns(0, 1, parent); // this creates a single column for children of the item
for (int i = 0; i < connectionData.size(); ++i) {
    model->insertRows(0, 1, parent);
    QModelIndex index = model->index(i, 0, parent);
    model->setData(index, connectionData[i]);
}

QStandardItemModel *model = new QStandardItemModel();
int parentrow = 2; // top level row number you wish to create offsprings for
QStringList connectionData;
connectionData << "Con1" << "Con2" << "Con3" << "Con4";
QModelIndex parent = model->index(parentrow, 0);
model->insertColumns(0, 1, parent); // this creates a single column for children of the item
for (int i = 0; i < connectionData.size(); ++i) {
    model->insertRows(0, 1, parent);
    QModelIndex index = model->index(i, 0, parent);
    model->setData(index, connectionData[i]);
}

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[jpn]

Go through and try to understand the following code:

void ServerList::addItem( const QString &hostName, quint16 port, const QString& username,
						 const QString& password, quint16 timeout, quint16 numberConnections )
{
	// first, insert a top level row
	int rows = model()->rowCount();
	model()->insertRow( rows );
 
	// set host name to the index in the first 
	// column of the newly inserted row
	QModelIndex parent = model()->index( rows, 0 );
	model()->setData( parent, hostName );
 
	//Server ns( hostName, port, username, password, timeout, numberConnections );
	//server.append( ns );
 
	// add a column and enough rows for connection children
	// the parent is the parent we just inserted above
	model()->insertColumn( 0, parent );						// one column for children
	rows = model()->rowCount( parent );
	model()->insertRows( rows, numberConnections, parent );	// one row for each child
 
	// set connection names for each children
	for ( int x = 0; x < numberConnections; x++ )
	{
		QModelIndex child = model()->index( x, 0, parent );		// all connections are under the same parent
																// which is, again, the same parent we
																// inserted in the first place
		model()->setData( child, QString("Connection #%1").arg( x + 1 ) );
	}
}

void ServerList::addItem( const QString &hostName, quint16 port, const QString& username,
						 const QString& password, quint16 timeout, quint16 numberConnections )
{
	// first, insert a top level row
	int rows = model()->rowCount();
	model()->insertRow( rows );

	// set host name to the index in the first 
	// column of the newly inserted row
	QModelIndex parent = model()->index( rows, 0 );
	model()->setData( parent, hostName );

	//Server ns( hostName, port, username, password, timeout, numberConnections );
	//server.append( ns );

	// add a column and enough rows for connection children
	// the parent is the parent we just inserted above
	model()->insertColumn( 0, parent );						// one column for children
	rows = model()->rowCount( parent );
	model()->insertRows( rows, numberConnections, parent );	// one row for each child

	// set connection names for each children
	for ( int x = 0; x < numberConnections; x++ )
	{
		QModelIndex child = model()->index( x, 0, parent );		// all connections are under the same parent
																// which is, again, the same parent we
																// inserted in the first place
		model()->setData( child, QString("Connection #%1").arg( x + 1 ) );
	}
}

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[Valheru]

Thanks, that works perfectly. I'm now just trying to puzzle out why