How to select child's items checkBoxs in QTreeView when select their parent's checkbox - qt

Question

I want to select/unselect all child's items QCheckBoxs when I select/unselect their parent's item QCheckBox.
i inherit from QTreeView and detect when the QCheckBox is selected then i call function to do selecting/unselecting process.
here my code:
#ifndef MYQTREEVIEW_H
#define MYQTREEVIEW_H
#include <QTreeView>
#include <QMouseEvent>
#include <QDebug>
#include <QStandardItem>
class MyQTreeView: public QTreeView {
public:
MyQTreeView(QWidget* parent=0): QTreeView(parent){}
virtual ~MyQTreeView() {}
protected:
void resettingCheckBox (QModelIndex& parentIndex) {
if ( ! parentIndex.isValid() )
return;
QString text = parentIndex.data( Qt::DisplayRole ).value<QString>();
qDebug() << "parent is: " << text;
if ( model()->hasChildren(parentIndex) ) {
for( int i = 0; i < model()->rowCount(parentIndex) ; i++ ) {
QModelIndex childIndex = model()->index( i, 0, parentIndex );
if ( model()->hasChildren(childIndex) )
resettingCheckBox(childIndex);
else {
QString text = childIndex.data( Qt::DisplayRole ).value<QString>();
qDebug() << "child is: " << text;
QStandardItem *parentItem = static_cast<QStandardItem*> (parentIndex.internalPointer());
QStandardItem *childItem = static_cast<QStandardItem*> (childIndex.internalPointer());
if ( parentItem->checkState() == Qt::Checked ) {
qDebug() << "child item " << childItem->checkState();
childItem->setCheckState( Qt::Unchecked);
}
else {
qDebug() << "child item " << childItem->checkState();
childItem->setCheckState( Qt::Checked);
}
}
}
}
}
void mousePressEvent (QMouseEvent *event) {
QModelIndex index = indexAt(event->pos());
if(index.isValid()) {
QStyleOptionButton opt;
opt.QStyleOption::operator=(viewOptions());
opt.rect = visualRect(index);
QRect rect = style()->subElementRect(QStyle::SE_ViewItemCheckIndicator, &opt);
if (rect.contains(event->pos())) {
resettingCheckBox(index);
}
QTreeView::mousePressEvent(event);
}
}
};
#endif // MYQTREEVIEW_H
the code is not working probably when i select/unselect parent checkBox (subchilds is not selected/unselected).
Thanks in advance.

Answer 1

I believe the best way to manipulate treeview items is through the model. It looks like you're using QStandardItemModel; so you can override your model's setData method and reset child items values for the item index passed as a parameter to this method. Below is a small example:
class TestModel : public QStandardItemModel
{
public:
TestModel() {}
bool setData(const QModelIndex & index, const QVariant & value, int role = Qt::EditRole)
{
QStandardItem *item = itemFromIndex(index);
for( int i = 0; i < item->rowCount() ; i++ )
{
QStandardItem *childItem = item->child(i);
setData(childItem->index(), value, role);
}
return QStandardItemModel::setData(index, value, role);
}
};
here's how this model gets initialized:
QStandardItemModel* tableModel = new TestModel();
QStandardItem* parentItem = tableModel->invisibleRootItem();
for (int i = 0; i < 4; ++i)
{
QStandardItem *item = new QStandardItem(QString("item %0").arg(i));
item->setCheckable(true);
parentItem->appendRow(item);
parentItem = item;
}
treeView->setModel(tableModel);
hope this helps, regards

Answer 2

It seems to me that you should call QTreeView::mousePressEvent(event) before resettingCheckBox(index), to let QTreeView update the checkState.

Answer 3

override mouseReleaseEvent() instead of mousePressEvent()!
because the checkState changes when mouse Release not mouse - press!