Details
-
Bug
-
Resolution: Done
-
P3: Somewhat important
-
5.12.0
-
Versions: Qt 5.12.0, Qt. 5.11.3, GCC64 bit on Fedora 28
-
Linux/X11
-
32de8dce311ddc562f88db47149c702fe9dcc950 (qt/qtdeclarative/5.12)
Description
If I move an Item of a DelegateModel within one of its groups (DelegateModelGroup), the `changed` signal is emitted for another group.
Let's say I have a DelegateModel with it's standard `items` group and an additional `visible` group:
DelegateModel {
id: delegateModel
model: fruitModel
delegate: delegate
filterOnGroup: "visible"
groups: [
DelegateModelGroup {
id: visibleGroup
name: "visible"
includeByDefault: false
}
]
}
Let's say I added all items to the visible group and move them around within that group using visibleGroup.move. This always causes the items group to emit the changed signal, even though no member in the items group has been inserted or removed and the move of an item was performed for visibleGroup.
Summarized:
delegateModel.items.onChanged = function (){
console.log("Changes in items");
}
// move item in visibleGroup
visibleGroup.move(visibleGroup.count - 1, 0, 1); // causes: "Changes in items"
If this was intended behaviour, the documentation of DelegateModel would lack clarity.
The following example illustrates the problem in detail. Every 800ms, the visible items are moved around and the items group always receives a signal.
import QtQuick.Window 2.2 import QtQuick 2.6 import QtQuick.Controls 2.0 import QtQuick.Layouts 1.3 import QtQml.Models 2.11 Window { visible: true width: 640 height: 480 title: qsTr("Error 1") ListView { anchors.fill: parent model: delegateModel } DelegateModel { id: delegateModel model: fruitModel delegate: delegate filterOnGroup: "visible" groups: [ DelegateModelGroup { id: visibleGroup name: "visible" includeByDefault: false } ] function parameterToString(parameter) { var result = ""; for(var i=0; i<parameter.length; ++i) { if(result.length>0) result = result + ", " result = (result + "[" + parameter[i].index + ", " + parameter[i].count + "]"); } return "{" + result + "}"; } items.onChanged: { console.log("items.onChanged", parameterToString(removed), parameterToString(inserted)); } } Component { id: delegate Rectangle { anchors.left: parent.left anchors.right: parent.right height: 30 Text { text: "Data: " + name + " costs " + cost } } } ListModel { id: fruitModel ListElement { name: "Apple" cost: 2.45 } ListElement { name: "Orange" cost: 3.25 } ListElement { name: "Banana" cost: 1.95 } ListElement { name: "Ananas" cost: 1.95 } ListElement { name: "Pear" cost: 1.95 } ListElement { name: "Grapes" cost: 1.95 } ListElement { name: "Lemon" cost: 1.95 } ListElement { name: "Apricot" cost: 1.95 } } Timer { id: changeModelTimer property int count: 0 interval: 800 onTriggered: { count++; console.log("Iteration", count); visibleGroup.move(visibleGroup.count - 1, 0, 1); if(count>=100) { Qt.quit() } } repeat: true } Component.onCompleted: { delegateModel.items.setGroups(0, delegateModel.items.count, ["items"]); delegateModel.items.addGroups(0, delegateModel.items.count, ["visible"]); changeModelTimer.start(); } }