QSortFilterProxyModel not working with a QAbstractListModel derived model.
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@ NewModel model;
QAbstractItemModel * pm = qobject_cast<QAbstractItemModel *>(&model);
QSortFilterProxyModel proxy;
proxy.setSourceModel(pm);
proxy.setSortRole(NewModel::WordRole);
proxy.setDynamicSortFilter(true);@This is what I tried, but it doesn't seem to work. The ListView in QML is able to pick up the model through the proxy, but there is no sorting. Am I doing something wrong?
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You allocate your proxy on the stack, so it will be destroyed at the end of the function hence no sorting. You have to allocate it on the heap to keep it and get your sorting.
I think Konstantin was just saying the it was a simple mistake that we all do/did from time to time.
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The stack is also the one which instantiates the application so everything allocated there lives for the duration of the application. If Konstantin wasn't so hasty to plant his insult he'd figure it out. And what is worse, absent any information related to the subject, the essence of his post boils down to the contained insult. Oh, let's not forget the abysmal grammar too...
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I have to disagree i.e.
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int main(int argc, char *argv[]
{
QApplication app(argc, argv);
QWidget w;
{
NewModel model;
QAbstractItemModel * pm = qobject_cast<QAbstractItemModel *>(&model);
QSortFilterProxyModel proxy;
proxy.setSourceModel(pm);
proxy.setSortRole(NewModel::WordRole);
proxy.setDynamicSortFilter(true);
}
// both model and proxy have now been destroyed because they are out of scope
w.show()
return app.exec();
}@ -
About 2 seconds of thought should be enough to determine that failure to sort could not possibly be the result of trying to use a deleted local object. I'd expect to get a serious runtime error if I try to use a non-existent object as a model, don't you think?
Your solidarity is heartwarming but in this particular case misplaced. There is absolutely nothing to hint that the sorting proxy fails to sort because of a dangling reference, nor any possible way to even reference an entirely local object outside of its scope short of an external handle to reach it. I honestly see no point in you defending a hasty "dumb" post absent thought or helpfulness.
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About 2 seconds of thought is enough to imagine few more "dumb" mistakes in the code you didn't show: missing Q_OBJECT macro, not deriving from QAIM, not calling sort() on a column of interest, not supporting NewModel::WordRole role in the model, etc.
Check if sorting doesn't work to you with some proven model, i.e. QStandardItemModel: if it doesn't, see what's wrong with the view.
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bq. About 2 seconds of thought is enough to imagine few more “dumb” mistakes in the code you didn’t show: missing Q_OBJECT macro, not deriving from QAIM, not calling sort() on a column of interest, not supporting NewModel::WordRole role in the model, etc.
Konstantin - I see you are firm on the course of making premature statements absent thought:
- Q_OBJECT is not missing
- I need a list model, thus I implement a QAbstractListModel
- there is but a single column in the model
- WordRole is supported in the model
There is no need to participate if you have nothing of value to contribute with, I am sure the internet offers plenty of other places for you to troll around...
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Sorry, I didn't realize this is a "here are 6 meaningless lines of code, guess what's wrong besides them" game.
Check if sorting doesn’t work to you with some proven model, i.e. QStandardItemModel: if it doesn’t, see what’s wrong with the view.
Still valuable ^
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bq. Sorry, I didn’t realize this is a “here are 6 meaningless lines of code, guess what’s wrong besides them” game.
Obviously, you were playing a different game right from the start, the game of premature offensive random statements. It is funny and ironic that you above all speak of meaningless lines... Sorry to cut your poopscapade short, but I doubt further input will be much more beneficial than what you "contributed" so far. Thanks a lot, couldn't have done it without you ;)
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I had the same problem, but it was because I wasn't calling sort on the proxy. I have come across a problem which I don't understand and one of you might.
I have a qml file that worked fine when using a QAbstractListModel, but when I apply a QSortFilterProxyModel to it the qml spits out ReferenceError, documentViewer is not defined.
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Rectangle {
id: documentViewer
color: "#E5E5E5"
clip: true
visible: false
focus:true
border.width: 0property bool isInSelectionMode: false property int thumbNailWidth: 152 property int thumbNailHeight: 152 property int thumbNailTopMargin: 5 property int thumbNailBottomMargin: 45 property int thumbNailLeftMargin: 22 property int thumbNailRightMargin: 22 Component { id: modelDelegate Rectangle { id: imageRect width: thumbNailLeftMargin + thumbNailRightMargin + thumbNailWidth height: thumbNailTopMargin + thumbNailBottomMargin + thumbNailHeight color: "transparent" border.color: "transparent" Item { id: thumbNail x: thumbNailLeftMargin y: thumbNailTopMargin width: documentViewer.thumbNailWidth height: documentViewer.thumbNailHeight Image { id: thumbNailImage anchors.fill: parent clip: true source: imageSource sourceSize.width: documentViewer.thumbNailWidth sourceSize.height: documentViewer.thumbNailHeight } MouseArea { id: mouseArea anchors.fill: parent onPressAndHold: { if(isItemSelectable && !documentViewer.isInSelectionMode) { isItemSelected = !isItemSelected; documentViewer.isInSelectionMode = !documentViewer.isInSelectionMode; } } onPressed: { if(documentViewer.isInSelectionMode && isItemSelectable) { isItemSelected = !isItemSelected; mouse.accepted = true; } } onClicked: { if(documentIndex == 0 && !documentViewer.isInSelectionMode) { DocumentManager.NewDocument(); documentViewer.done(1); } else if(documentIndex != 0 && !documentViewer.isInSelectionMode) { DocumentManager.OpenDocument(name); documentViewer.done(1); } } } } }}
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I have a list view that used this delegate, but I haven't showed it in this code snippet. I don't get why when I apply the QALM on the ListView it has no problem determining what documentViewer is, but when I apply QSFPM it gives me a reference error. Any ideas?
