[newbie] Set background of specific row in QListView

Hi,

I've found this: https://forum.qt.io/topic/76265/set-...-in-qtableview
I have copied the setRowColor() from the link above into my code base call it like:

Code:

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void Widget::on_HostList_doubleClicked(const QModelIndex &index)
{
    QAbstractItemModel *model = ui->HostList->model();
    setRowColor(model,index.row(),Qt::red,index);
}

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but it does not seem to work, the color is not changing. Can someone help me here?

Quote:

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ui->HostList->model()

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What is your model? Have you implemented the setData() method on it? If so, have you implemented it for the Qt:: BackgroundRole role?

Hi d_stranz,

Thanks for your reply,
I'm using a QStringListModel and my data gets populated as follows:

Code:

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int JTFTools::ListViewPopulate(QListView *listView, QStringList *stringList)
{
    int rv = OK;
 
    QStringListModel* listModel = new QStringListModel(*stringList, listView);
    QItemSelectionModel *oldModel = listView->selectionModel();
    listView->setModel(listModel);
 
    delete oldModel;
 
    return rv;
}

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setData() is here: http://doc.qt.io/qt-5/qstringlistmodel.html#setData but I couldn't find Qt:: BackgroundRole, how do I go about this?
Thanks!

Quote:

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I have copied the setRowColor() from the link above into my code base call it like

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And you implemented this -exact- code, right?

Code:

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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);
}

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"BackgroundRole" is one of the Qt::ItemDataRole enums.

Does this function work if you call it from somewhere beside the double-click slot? For example, in your ListViewPopulate method, what happens if you populate the list, then run a loop that sets every even-numbered entry to red background?

Code:

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for ( int nRow = 0; nRow < listModel->rowCount(); nRow += 2 )
  setRowColor( listModel, nRow, Qt::red );

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By the way, your code in ListViewPopulate is a memory leak. Each time the function executes, it creates a new list model and sets it on the view, but you never delete the old list model (listView->model()). Instead for some strange reason, you delete the selection model (which is entirely different from the string list model you create and set on the view).

Thank you d_stranz and everyone else involved ,
for future reference, I got an excellent working example here: https://forum.qt.io/post/418663

Quote:

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I got an excellent working example here

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And I hope you realize that the critical line from that example:

Code:

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// set the bg color of row 2
    model->setData(model->index(1, 0), QBrush(Qt::red), Qt::BackgroundRole);

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is no different from what you posted in the setRowColor() code and is no different from what I suggested to you to try in my previous post, right?

Quote:

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Originally Posted by d_stranz

And I hope you realize that the critical line from that example:

Code:

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// set the bg color of row 2
    model->setData(model->index(1, 0), QBrush(Qt::red), Qt::BackgroundRole);

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is no different from what you posted in the setRowColor() code and is no different from what I suggested to you to try in my previous post, right?

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Yes, I definitely do and that the problem is with QStringListModel not supporting the color setting, but QStandardItemModel in place works properly.

Quote:

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Yes, I definitely do and that the problem is with QStringListModel not supporting the color setting, but QStandardItemModel in place works properly.

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Good to know this. That's something that is not in the documentation and should be.