QStandardItem setBackground in delegate makes grid disappears in tableView

Question

I am using a delegate to set one cell's background to be blue in tableView. The code like follows:

void Delegate::setModelData(some parameters) 
{
     QStandardItem *item = model->item(modelIndex);
     item->setBackground(QBrush(Qt::blue));
     item->setText("hello")
}

1. In this sequence, setBackground is before setText, the text won't show.If I change the sequence, text can show.
2. If I change the background in this way, the grid line of the table disappears, like following:

Though not very clear(blue background), you still can see in the last column, no grid-line to seperate the cell.

Could you please tell me what is wrong with these two problems, and how to solve them? Thank you very mush ahead.

Answer 1

setModelData() that the place for save data form your custom editor to model. You should setup cell drawing at paint() virtual function:

void Delegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
// Your manipulation with QPainter and QStyleOptionViewItem
QStyledItemDelegate::paint(painter, &option, &index);
}

You should change QStyleOptionViewItem::backgroundBrush