Get geometry of a row in QTreeView

Lurkki

I want to be able to make an editor in my custom delegate span all columns on demand. I'm trying to do it with a subclassed QStyledItemDelegate and QTreeView as follows:

    // Subclassed QTreeView
    QRect rowGeometry(const QModelIndex &index) {
        int indent = (index.column() + 1) * indentation();
        int firstSection = header()->logicalIndex(0);
        int lastSection = header()->logicalIndex(header()->count() - 1);
        int left = header()->sectionViewportPosition(firstSection);
        int right = header()->sectionViewportPosition(lastSection) + header()->sectionSize(lastSection);

        left += indent;

        QPoint rowTopLeft(rect().topLeft().x() + indent, rect().topLeft().y() + rowHeight(index) * (index.row() + 1);
        QRect rec(rect().topLeft(), QSize(right - left, rowHeight(index)));
        return rec;
    }

    // Subclassed QStyledItemDelegate
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const {
        editor->setGeometry(m_subclassedTreeView->rowGeometry(index));
    }

The result is that the editor doesn't follow the indentation, and is always on row 0. I'm also open to accomplishing this some other way.

SGaist

Hi,

Can you provide a minimal compilable example that shows that behaviour ?

Lurkki

#include <QTreeView>
#include <QHeaderView>
#include <QStyledItemDelegate>
#include <QStandardItemModel>
#include <QVBoxLayout>

class ExpandableTreeView : public QTreeView {
public:
    ExpandableTreeView(QWidget *parent = nullptr) : QTreeView(parent) {
    }
    void setExpandableIndex(const QModelIndex &index) {m_expandableIndex = index;}
    QRect rowGeometry(const QModelIndex &index) {
        int indent = (index.column() + 1) * indentation();
        int firstSection = header()->logicalIndex(0);
        int lastSection = header()->logicalIndex(header()->count() - 1);
        int left = header()->sectionViewportPosition(firstSection);
        int right = header()->sectionViewportPosition(lastSection) + header()->sectionSize(lastSection);

        left += indent;

        QPoint rowTopLeft(rect().topLeft().x() + indent, rect().topLeft().y() + rowHeight(index));
        QRect rec(rect().topLeft(), QSize(right - left, rowHeight(index)));
        return rec;
    }
private:
    QModelIndex m_expandableIndex;
};

class ExpandableDelegate : public QStyledItemDelegate {
public:
    ExpandableDelegate(QObject *parent = nullptr) : QStyledItemDelegate(parent) {}
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const {
        return QStyledItemDelegate::sizeHint(option, index);
    }
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const {
        QRect geo = m_eview->rowGeometry(index);
        editor->setGeometry(geo);
    }
    void setExpandableIndex(const QModelIndex &index) {m_expandableIndex = index;}
    void setExpandableTreeView(ExpandableTreeView *view) {m_eview = view;}
private:
    QModelIndex m_expandableIndex;
    ExpandableTreeView *m_eview;
};

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    auto central = new QWidget;

    auto lo = new QVBoxLayout;

    auto model = new QStandardItemModel;

    auto root = model->invisibleRootItem();

    auto view = new ExpandableTreeView;

    QList <QStandardItem*> rowItems;
    for (int i = 0; i < 3; i++) {
        auto item = new QStandardItem;
        item->setText(QString::number(i));
        rowItems.append(item);

        auto i2 = new QStandardItem;
        i2->setText(QString::number(i + 1));
        rowItems.append(i2);


        root->appendRow(rowItems);
        rowItems.clear();
    }
    auto delegate = new ExpandableDelegate;
    delegate->setExpandableTreeView(view);

    view->setItemDelegate(delegate);
    view->setModel(model);

    lo->addWidget(view);

    central->setLayout(lo);

    setCentralWidget(central);

    connect(view, &ExpandableTreeView::activated, [=](const QModelIndex &index) {
        delegate->setExpandableIndex(index);
    });
}

VRonin

I think this could be easily solved by just using visualRect() in the delegate:

void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &, const QModelIndex &index) const {
    const int maxCol = index.model()->columnCount(index.parent());
    QRect tempRect = m_subclassedTreeView->visualRect(index.model()->index(index.row(),0,index.parent()));
    int top = tempRect.top();
    int left = tempRect.left();
    int bottom = tempRect.bottom();
    int right= tempRect.right();
    for(int i = 1;i<maxCol ;++i){
        tempRect =m_subclassedTreeView->visualRect(index.model()->index(index.row(),i,index.parent()));
        if(tempRect.top()<top)
            top = tempRect.top();
        if(Q_UNLIKELY(tempRect.left()<left))
            left= tempRect.left();
        if(tempRect.bottom()>bottom)
            bottom = tempRect.bottom();
        if(Q_LIKELY(tempRect.right()>right))
            right= tempRect.right();
    }
    editor->setGeometry(QRect(QPoint(top,left),QPoint(bottom,right)));
}

Lurkki

@VRonin That works though I had to change editor->setGeometry(QRect(QPoint(top, left),QPoint(bottom, right))); to editor->setGeometry(QRect(QPoint(left, top),QPoint(right, bottom)));

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Get geometry of a row in QTreeView