Programmatically change the background color of a QModelIndex role

phamtv

My application contains a QTreeView that displays a custom QSortFilterProxyModel class using a QFileSystemModel as its source. I want to programmatically change the background color of the QModelIndex I am working with (basically yellow, green, and red indicating in progress, pass, fail for the file I am processing). How can I programmatically change the background color for selected index of Treeview control? Keep in mind that the current view has a alternating color scheme that I would like to keep just in case I have not dealt with the file yet.

noah

The standard method is to override the data method in your model and return the required color for the BackgroundRole

@QVariant MyModel::data ( const QModelIndex & item, int role ) const
{
//change the background color
if (role == Qt::BackgroundRole)
{
return QColor(255, 0, 0);
}

return QSortFilterProxyModel::data(item, role);
}@

phamtv

Thanks Noah.. However, how can I preserve the alternating row color for files (rows) I have processed?

noah

If you don't want to set the color for a specific row just fall through to the default. You'll have do something a bit more complicated than my code to determine the appropriate color, obviously.

@QVariant MyModel::data ( const QModelIndex & item, int role ) const
{
//change the background color
if (role == Qt::BackgroundRole)
{
if (item.data() = "In Progress")
return QColor(255, 255, 0); //yellow
else if (item.data() = "Fail")
return QColor(255, 0, 0); //red
else if (item.data() = "Pass")
return QColor(0, 255, 0); //green
//else fall through to the default alternating background color
}

return QSortFilterProxyModel::data(item, role);
}@

phamtv

it works! thanks Noah!

StephanB

Thank you for your answers on this question. I found this topic and it has been very helpful. Would you be able to provide your code that calls this function to change the background color?

Thanks!

mrjj

@StephanB
hi and welcome
The thread is 4 years old so the persons are most likely never to see it.

The rest of the code belong to a custom/subclass model.
So what call the code, it the framework / the view that use this model.

You can read about it here:
http://doc.qt.io/qt-5/model-view-programming.html
https://www.youtube.com/watch?v=ytKDsJgJa4k
http://www.informit.com/articles/article.aspx?p=1405547&seqNum=3