Getting Information back out of QListWidgetItem that has a QMap in it

resist95

Hi im trying to figure out how I can get Information out of a QListWidgetItem.
I have program that has a QMap

QMap<int,std::tuple<QString,QString,QString>>map; 
 map.insert(5,std::make_tuple("A","b","c"));

I insert this map into a QListWidget like this

    QMapIterator<int,std::tuple<QString,QString,QString>> i(map);
    QString name;
    int id;
    while(i.hasNext()){
        i.next();
        name = std::get<0>(i.value());
        id = i.key();
        //qDebug () << i.key() << " " << std::get<0>(i.value());
        QListWidgetItem *item = new QListWidgetItem(name);
        item->setData(Qt::UserRole, id);
        ui->uebungs_liste->addItem(item);
    }

uebungs_liste is the QListWidget and item the QListWidgetItem

Now I want to access the information of the QListWidgetItem when you click on it how do I i go about achieving this.

JonB

@resist95
[signal]void QListWidget::itemClicked(QListWidgetItem *item) signal is emitted for you to slot into. The fact that you happen a store a map as data is neither here nor there to retrieval.

resist95

ok so once i insert it into the list the information is gone?

JonB

@resist95
No, if you inserted it with item->setData(Qt::UserRole, id); you can retrieve it with int id = item->data(Qt::UserRole);.

resist95

@JonB
im very new to Qt and the item->setData(Qt::UserRole,id) line was from a tutorial could you elaborate how I get the Information out of the item or point me towards a tutorial where I can look it up.

JonB

@resist95
Well, I would have expected that tutorial surely to show you how you retrieve the data set via setData()?

What can I say, given that I've given already typed in the statement you need?

connect(myListWidget, &QListWidget::itemClicked, this, &MainWindow::onListWidgetItemClicked);
...
void MainWindow::onListWidgetItemClicked(QListWidgetItem *item)
{
    # next line retrieves `id` set from previous `item->setData(Qt::UserRole, id);`
    QVariant v = item->data(Qt::UserRole);
    bool ok;
    int id = v.toInt(&ok);
    if (ok)
        qDebug() << id;
}

resist95

@JonB
It sadly didnt also your code returns no viable conversion int to qvariant it should be

QVariant id = item->data(Qt::UserRole)

but anyway thank you ill try to figure out the rest myself

JonB

@resist95
Yes, you can use [I have corrected my answer]:

QVariant v = item->data(Qt::UserRole);
bool ok;
int id = v.toInt(&ok);
if (ok) ...

or whatever is necessary for your exact situation.