How to judge class object is null ?

[sonichy]

TileItem::TileItem(QGraphicsItem *parent) : QGraphicsPixmapItem(parent)
{

}

TileItem::TileItem(QString &surl)
{
    setPixmapFormUrl(surl);
}

void TileItem::setPixmapFormUrl(QString surl)
{
    QNetworkAccessManager *NAM = new QNetworkAccessManager;
    QNetworkRequest request;
    request.setUrl(QUrl(surl));
    NAM->get(request);
    connect(NAM, &QNetworkAccessManager::finished, [=](QNetworkReply *reply){
        QPixmap pixmap;
        pixmap.loadFromData(reply->readAll());
        //if(TileItem) 
            setPixmap(pixmap);//if it is deleted in parent, here will crash.
        NAM->deleteLater();
    });
}

[VRonin]

Not sure I understand the question...

[SGaist]

@sonichy hi,

I would say that your design has issues. Creating a QNAM for each tile when you want to a remote image is rather wasteful.

You should rather have a dedicated class that manages the retrieval of the images and setting them on the appropriate tile. That way you can also cancel the retrieval on tile deletion.