QListWidget::itemChanged signal triggered twice in qt - c++

Question

I have a QListWidget to store usernames, and I use this signal to detect if username is being changed:
connect(listWidget, &QListWidget::itemChanged, this, &MainWindow::changeUserName);
void MainWindow::changeUserName(QListWidgetItem *editItem)
{
qDebug() << "Name:" << editItem->text();
}
And this is how I make QListWidget editable in another function:
connect(listWidget, &QListWidget::itemDoubleClicked, this, &MainWindow::makeListEditable);
void MainWindow::makeListEditable()
{
QListWidgetItem *editItem = listWidget->currentItem();
editItem->setFlags(editItem->flags() | Qt::ItemIsEditable);
qDebug() << "Name edit";
}
But which confused me is, whenever I double clicked the list widget, the itemChanged signal will be triggered once, and when I input a new username, the signal will be triggered again. Why would this happen?
This is the debug output, when I double clicked the list, it says:
Name: "Testing name_1"
Name edit
after I entered a new name and hit the enter, it says:
Name: "Testing name_2" //a new name I changed to
And what if I only want a signal be triggered once whenever I input a new name and hit the enter, what should I do to achieve this?
Thanks

Answer 1

You can use the item delegate commitData signal, this way:
QObject::connect(listWidget->itemDelegate(), SIGNAL(commitData(QWidget*)), this, SLOT(dataCommited(QWidget*)));
the slot is like this:
void dataCommited(QWidget * w)
{
QString data = (static_cast<QLineEdit *>(w))->text();
//...
}
The signal will be emitted at the end of the editing (i.e. enter key pressed or focus lost etc.)

Answer 2

As #Rafalon said, calling setFlags calls your slot changeUserName, and the signal currentTextChanged is emitted when the current item changed, it is the same as currentItemChanged except it gives you the text instead of the item.
What you can do is, make your item editable as you instantiate it:
QListWidgetItem* pItem = new QListWidgetItem();
pItem->setText("Testing name_1");
pItem->setFlags(pItem->flags() | Qt::ItemIsEditable);
listWidget->addItem(pItem);
or you can activate/deactivate the connection when you need it:
void MainWindow::makeListEditable(QListWidgetItem *editItem)
{
editItem->setFlags(editItem->flags() | Qt::ItemIsEditable);
connect(ui->listWidget, SIGNAL(itemChanged(QListWidgetItem *)), this, SLOT(changeUserName(QListWidgetItem *)));
qDebug() << "Name edit";
}
void MainWindow::changeUserName(QListWidgetItem *editItem)
{
qDebug() << "Name:" << editItem->text();
disconnect(ui->listWidget, SIGNAL(itemChanged(QListWidgetItem *)), this, SLOT(changeUserName(QListWidgetItem *)));
}
but you will have to make another connection when the current element is not modified after a double click, maybe with the signal currentItemChanged.