how to updating a view's proxy model when the source model changes.

[Yash001]

CustomListModel.h File

class CustomListModel : public QStandardItemModel
{
public:
   CustomListModel(QObject* parent = 0);
   CustomListModel(const int row, const int coloumn, QObject *parent = 0);
   Qt::ItemFlags flags(const QModelIndex& index) const;
   QVariant data(const QModelIndex &index, int role) const;
   bool setData(const QModelIndex &index, const QVariant &value, int role);
private:
   QSet<QPersistentModelIndex> checkedItems;
};

CustomListModel.cpp File

CustomListModel::CustomListModel(QObject *parent) :
	QStandardItemModel(parent) {
}

CustomListModel::CustomListModel(const int row,const int coloumn, QObject *parent) :
	QStandardItemModel(row,coloumn) {
}

Qt::ItemFlags CustomListModel::flags(const QModelIndex & index) const {
	Qt::ItemFlags defaultFlags = QStandardItemModel::flags(index);
	if (index.isValid()) {
		
		return defaultFlags | Qt::ItemIsUserCheckable;
	}
	return defaultFlags;
}


QVariant CustomListModel::data(const QModelIndex &index,
	int role) const {
	if (!index.isValid())
		return QVariant();

	if (role == Qt::CheckStateRole)
	{
		return (checkedItems.contains(index) ? Qt::Checked : Qt::Unchecked);
	}

	return (QStandardItemModel::data(index, role));
}

bool CustomListModel::setData(const QModelIndex &index,
	const QVariant &value, int role) {

	if (!index.isValid())	
		return false;

	if ((true)&&(role == Qt::CheckStateRole)) {
		if (value == Qt::Checked) {
			checkedItems.insert(index);
		}
		else {
			checkedItems.remove(index);
		}
		emit dataChanged(index, index);
	}

	else {
		QStandardItemModel::setData(index, value, role);
	}
	return true;
}


class HardwareProxyModel : public  QSortFilterProxyModel {
	bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const {
		QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
		
		if (!index.isValid()) {
			return false;
		}

		bool supportAc = index.data(Qt::UserRole + 1).toBool();

		bool ret = false;

		if ((!showOnlyAc) || (showOnlyAc && supportAc)) {
			ret = true;
		}

		return ret;
	}

public:
	void ShowOnlyAcHardware() {
		 showOnlyAc = true;
		 invalidateFilter();
	}
	void ShowAllHardware() {
		showOnlyAc = false;
		invalidateFilter();
	}

private:
	bool showOnlyAc = false;
};

mainUI.cpp file

auto hwList = new QListView;
auto hwListProxyModel = new HardwareProxyModel;
auto dummy = new CustomListModel(0, 0);
hwListProxyModel->setSourceModel(dummy);
hwList->setModel(hwListProxyModel);

//add item into model 
for (auto it = newLines.begin(); it != newLines.end(); ++it) {
      auto count = model->rowCount();
      model->insertRow(count);
      auto index = model->index(count, 0);
      model->setData(index, it->name, Qt::DisplayRole);
      model->setData(index, it->channelAmount, Qt::UserRole); 
      model->setData(index, Qt::Unchecked, Qt::CheckStateRole);
}

I like to change the value of check box for item. So that, I can change value with help of
hwListProxyModel->setData(hwList->currentIndex(), Qt::Checked, Qt::CheckStateRole);

but I would like to update checkbox with help of sourcemodel.
(source model name = dummy). so that i am trying with help of below line.
hwListProxyModel->sourceModel()->setData(hwList->currentIndex(), Qt::Checked, Qt::CheckStateRole);

but it is not updating view.

Here I found Some Documentation
similar question. http://www.qtcentre.org/threads/55962-Updating-a-view-s-proxy-model-when-the-source-model-changes

http://doc.qt.io/archives/qt-4.8/qsortfilterproxymodel.html#dynamicSortFilter-prop

How can I update the view if i will change the source model Data? I make many change but something I miss. Please any one give me direction. What change should I make?

[Yash001]

@mrjj any suggestion?

[Christian Ehrlicher]

@Yash001 said in how to updating a view's proxy model when the source model changes.:

hwList->currentIndex()

You're using the wrong model index . See mapToSource/mapFromSource: http://doc.qt.io/qt-5/qsortfilterproxymodel.html#mapToSource
You will also get a warning at runtime about the wrong model index usage.

[Yash001]

Thank you @Christian-Ehrlicher for your answer. I got check mark after getting guidance from you. Thank you so much.

[Yash001]

@Christian-Ehrlicher is it any way to determine, whether check box check mark is done by User Mouse Click or with help of coding like sourceModel->setData(hwListProxyModel->mapToSource(hwList->currentIndex()), Qt::Checked, Qt::CheckStateRole);?

I am trying to add another argument or Function before calling setData Function.

I wrote this function for differentiate Click

bool CustomListModel::setDataAndFilterCheckMarkClick(const QModelIndex &index, const QVariant &value, int role, bool ChannelSelected) {
	if (!index.isValid())
		return false;

	if ((ChannelSelected) && (role == Qt::CheckStateRole)) {
		if (value == Qt::Checked) {
			qDebug() << "click get from view ";
		}
		else {
			qDebug() << "click does not get from view";
		}
	}
	return this->setData(index, value, role);
}

checkbox is check whenever I wanted to do using coding. I used code line like
sourceModel->setDataAndFilterCheckMarkClick(hwListProxyModel->mapToSource(hwList->currentIndex()), Qt::Checked, Qt::CheckStateRole,true);

but if the user Click from the view then it won't selected.

I saw in Qcheckbox. which is give me position of the mouse pos.
bool QAbstractButton::hitButton(const QPoint & pos) const, but i don't know. how can we access the checkbox pointer from the model?

In general I would like to differentiate Check box Check from user and Check box check by Coding. what is good way to do this?

[VRonin]

Your QStandardItemModel is useless. QStandardItemModel can already manage Qt::CheckStateRole

In general I would like to differentiate Check box Check from user and Check box check by Coding. what is good way to do this?

While this is usually a sign of something in your design going wrong, you can subclass the delegate and reimplement editorEvent. You can start by looking at the source: https://code.woboq.org/qt5/qtbase/src/widgets/itemviews/qstyleditemdelegate.cpp.html#_ZN19QStyledItemDelegate11editorEventEP6QEventP18QAbstractItemModelRK20QStyleOptionViewItemRK11QModelIndex

[Yash001]

@VRonin Thank you for giving me direction. let me trying with QStyledItemDelegate.

[Yash001]

@VRonin How can i access the checkbox Pointer, So i can identify the pointer of mouse is inside the Checkbox or not?

If I will get access for class QStyledItemDelegatePrivate. then I can get access for the QCheckbox.
const QWidget *widget = QStyledItemDelegatePrivate::widget(option);

[VRonin]

if you look inside QStyledItemDelegatePrivate::widget(option); you'll see it is equivalent to option.widget;

[Yash001]

@VRonin Thank you. Yesterday, I tried same things. But it was not working than later on I found, I forget to add file name in SOURCE , HEADER. Now it is work as expectation.