Set background of specific row in QTableView

[t0msk]

Hello, please how can I set background of specific row (for example second) in QTableView (programmatically).

[VRonin]

You can set it at the model level (all views connected to the model are affected)

void setRowColor(QAbstractItemModel* model, int row, const QBrush& color, const QModelIndex& parent = QModelIndex()){
if(!model) return;
if(row<0 || row>=model->rowCount(parent)) return;
const int colCount = model->columnCount(parent);
for (int j = 0; j < colCount; ++j)
model->setData(model->index(row,j,parent),color,Qt::BackgroundRole);
}

or use a delegate for the specific view (the one below lets you specify the color for entire row and column and for individual cell):

#include <QStyledItemDelegate>
#include <QApplication>
#include <QHash>
class BackGroungColorDelegate : public QStyledItemDelegate
{
    Q_OBJECT
    Q_DISABLE_COPY(BackGroungColorDelegate);
public:
    explicit BackGroungColorDelegate(QObject *parent = Q_NULLPTR)
        :QStyledItemDelegate(parent){}
    virtual void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE{
    
        Q_ASSERT(index.isValid());

        QStyleOptionViewItem opt = option;
        initStyleOption(&opt, index);
        if (!index.parent().isValid()) {
            if (hasCellColor(index.row(), index.column()))
                opt.backgroundBrush = colorForCell(index.row(), index.column());
        }
        const QWidget *widget = option.widget;
        QStyle *style = widget ? widget->style() : QApplication::style();
        style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, widget);
    }
    void setColorForRow(int row, const QBrush& val){
        m_rowColors[row] = val;
    }
    QBrush colorForRow(int row) const {
        return m_rowColors.value(row);
    }
    void removeColorForRow(int row){
        m_rowColors.remove(row);
    }
    void clearRowColors(){
        m_rowColors.clear();
    }
    void setColorForCol(int col, const QBrush& val)
    {
        m_colColors[col] = val;
    }
    QBrush colorForCol(int col) const
    {
        return m_colColors.value(col);
    }
    void removeColorForCol(int col)
    {
        m_colColors.remove(col);
    }
    void clearColColors()
    {
        m_colColors.clear();
    }
    void setColorForCell(int row, int col, const QBrush& val){
        m_cellColors[cellKey(row, col)] = val;
    }
    QBrush colorForCell(int row, int col) const
    {
        return m_cellColors.value(cellKey(row, col), m_rowColors.value(row, m_colColors.value(col)));
    }
    void removeColorForCell(int row, int col)
    {
        m_cellColors.remove(cellKey(row, col));
    }
    void clearCellColors()
    {
        m_cellColors.clear();
    }
private:
    QHash<quint64,QBrush> m_cellColors;
    QHash<int, QBrush> m_rowColors;
    QHash<int, QBrush> m_colColors;
    Q_DECL_CONSTEXPR quint64 cellKey(int row, int col) const
    {
        return (static_cast<quint64>(row) << 32) | static_cast<quint64>(col);
    }
protected:
    bool hasCellColor(int row, int col) const{
        return m_cellColors.contains(cellKey(row, col))
           || m_rowColors.contains(row)
           || m_colColors.contains(col);
    }
};