page switch delay when loading images to Image source

Marek

Hi

I have pages organized with StackView, lets say second page has ListView with Image elements (usually 3 elements), when I switch from first page to second app freezes for about 300ms when ListView is loading pictures from disk. How to make ListView load its pictures after page is switched? I was experimenting with stackView onCurrentItemChanged but it looks like the currentItem is changed before it is really shown, I was adding some delays in PictureModel that provides file names for ListView but it does not work well.
Or maybe some other idea? Load pictures in C++ part maybe in separate thread and pass somehow content to QML ListView?
Parts of my code below:

//ListView from second page
ListView {
    id: plantPicView
    snapMode: ListView.SnapOneItem
    highlightRangeMode: ListView.StrictlyEnforceRange
    orientation: Qt.Horizontal
    width:(PictureModel.rows ? parent.width : 0)
    height:(PictureModel.rows ? 3*width/4 : 0)
    anchors.horizontalCenter: parent.horizontalCenter
    clip: true
    z:10

    model: PictureModel
    delegate: PictureDelegate {
        z:11
        source: pic_name_role
    }
    spacing: 0
}
//PictureDelegate.qml
Rectangle {
    id: root
    width:plantPicView.width
    height:plantPicView.height
    color: "lightgray"
    property alias source: imageItem.source
    Image {
        id: imageItem
        anchors.fill: parent
    }
}

// part of PictureModel
void PictureModel::setCatalogId(int catalog_id) {
   if(picMap.count()) {
        beginRemoveRows(QModelIndex(), 0, picMap.count()-1);
        QMapIterator<int,PictureModelDataStruct*> i(picMap);
        while(i.hasNext()) {
            i.next();
            delete i.value();
        }
        picMap.clear();
        endRemoveRows();
    }
    int row=0;
    QMap<int,PicDataStruct*> *pMap=catalogData->getPicMap(catalog_id);

    QMapIterator<int,PicDataStruct*> i(*pMap);
    while(i.hasNext()) {
        i.next();
        PictureModelDataStruct *p=new PictureModelDataStruct;
        p->pic_id=i.value()->pic_id;
        p->row=row;
        p->fileName=QString("%1%2_%3.jpg").arg(Zm().imagesPath).arg(catalog_id).arg(p->pic_id);
        p->available=1
        p->pic_desc=i.value()->pic_desc;
        picMap.insert(p->row,p);
        beginInsertRows(QModelIndex(), row, row);
        endInsertRows();
        row++;
    }
    m_rows=picMap.count();
    emit rowsChanged();
}

Best Regards
Marek

GrecKo

Have you tried putting asynchronous: true in your Image instead ?

Marek

@GrecKo would that be so simple? ;) I will check and let you know.
Thanks
Marek

Marek

@GrecKo thanks, obviously it works :)

Marek