[Solved] QML ListView delegate problem

Mixa84

I have a strange problem with ListView when I iterate over visible items in the view. I`m using this code to go over all the delegates that are instantiated currently in the view:

@for (var i = 0; i < messagelist.contentItem.children.length; i++)
{
var curItem = messagelist.contentItem.children[i];
console.log(i,": ", curItem, "=", curItem.messagetext);
}@

First time when I fill the model with data I get in the console output number of items visible +1. The first one is different type from the others:

bq. 0 : QDeclarativeItem(0xf5f500) = undefined
1 : MessageBox_QMLTYPE_5(0xbb63a0, "messagebox") = rewgrew
2 : MessageBox_QMLTYPE_5(0x14b1130, "messagebox") = g
3 : MessageBox_QMLTYPE_5(0x1333b30, "messagebox") = f
4 : MessageBox_QMLTYPE_5(0x1327e50, "messagebox") = f
5 : MessageBox_QMLTYPE_5(0x10169c0, "messagebox") = h
6 : MessageBox_QMLTYPE_5(0x13061e0, "messagebox") = f
7 : MessageBox_QMLTYPE_5(0x13585a0, "messagebox") = d
8 : MessageBox_QMLTYPE_5(0x1304f90, "messagebox") = f
9 : MessageBox_QMLTYPE_5(0x1500390, "messagebox") = h
10 : MessageBox_QMLTYPE_5(0x1116a50, "messagebox") = h
11 : MessageBox_QMLTYPE_5(0x1529f10, "messagebox") = f
12 : MessageBox_QMLTYPE_5(0x1164f90, "messagebox") = s
13 : MessageBox_QMLTYPE_5(0x132f090, "messagebox") = a
14 : MessageBox_QMLTYPE_5(0x1540070, "messagebox") = n
15 : MessageBox_QMLTYPE_5(0x14e04e0, "messagebox") = pppp
16 : MessageBox_QMLTYPE_5(0x1180bb0, "messagebox") = s
17 : MessageBox_QMLTYPE_5(0x1242250, "messagebox") = a
18 : MessageBox_QMLTYPE_5(0x1222830, "messagebox") = vvvvvvv
19 : MessageBox_QMLTYPE_5(0x100cbb0, "messagebox") = ggr
20 : MessageBox_QMLTYPE_5(0x13c8050, "messagebox") = grs
21 : MessageBox_QMLTYPE_5(0x14b0610, "messagebox") = cds
22 : MessageBox_QMLTYPE_5(0x149ce90, "messagebox") = ttt

If I clear the model and populate it with same data again that item disappears. I have tried with the model from C++, but also with some dummy model declared in QML with ListModel. Same thing happens. Cachebuffer is set to 0 by default.

Here is the code from test project where I made a small model and the view for it and where I get the same results:

@Rectangle {
width: 360
height: 360

ListModel
{
    id: settingspropmodel;
    ListElement { txt: "Mark all as read"}
    ListElement { txt: "Add people"}
    ListElement { txt: "Set topic"}
    ListElement { txt: "Set icon"}
    ListElement { txt: "Notifications off"}
    ListElement { txt: "Leave chat"}
}

ListView
{
    id: lv;
    boundsBehavior: Flickable.DragOverBounds
    clip: true

    anchors.fill: parent;

    onMovementEnded:
    {
        for (var i = 0; i < lv.contentItem.children.length; i++)
        {
            var curItem = lv.contentItem.children[i];
            console.log(i,": ", curItem, "=", curItem.msgtxt);
        }
        console.log("--------------------------------------------");
    }

    model: settingspropmodel
    delegate: Item
    {
        property string msgtxt: txt;
        Rectangle { width: parent.width; height: 1; x:0; y:0; border.color: "#cccccc"; border.width: 1}
        Text { id: proba1; width: parent.width;  x: 10; y:5; color: "#424242"; font.family: "Ubuntu Light"; font.pointSize: 10; wrapMode: Text.WordWrap; text: txt; textFormat:Text.RichText;}
        anchors.right: parent.right;
        anchors.left: parent.left;
        height: proba1.height+20;
    }
}

}@

chrisadams

Is the header component automatically parented to the view, perhaps?

Mixa84

I did not specify any header component, and it is strange that the unknown item is always second. Also if this was the header than it would appear after I repopulate the model too.

Roland_R

Could be the highlight (focus) item showing up here as child of the contentItem node.

Mixa84

I will checkout if this is the case, but I`m suspicious about that.

Mixa84

I have found out what is the cause of this problem. As Roland suggested that it could be the highlight item I started thinking in that way. Because I didnt set the currentIndex to -1 it was generating some kind of highlight even if I didnt specify anything for highlight.

Workaround for this is to set currentIndex to -1 on Component.onCompleted.