PyQt Tableview background color based on text value rather than True or False

Question

Follow up to my general question, where @eyllanesc has kindly answered my question.

Out of curiosity, I tried changing to code to check against a string rather than 1 and all the rows turned gray.

Original code from @eyllanesc:

def data(self, item, role):
    if role == Qt.BackgroundRole:
        if QSqlQueryModel.data(self, self.index(item.row(), 3), Qt.DisplayRole):
            return QBrush(Qt.yellow)
    if role == Qt.DisplayRole:
        if item.column() == 3:
            return True if QSqlQueryModel.data(self, item, Qt.DisplayRole) == 1 else False
    return QSqlQueryModel.data(self, item, role)

If I change it to

def data(self, item, role):
    if role == Qt.BackgroundRole:
        if QSqlQueryModel.data(self, self.index(item.row(), 2), Qt.DisplayRole):
            return QBrush(Qt.yellow)
    if role == Qt.DisplayRole:
        if item.column() == 2:
            return True if QSqlQueryModel.data(self, item, Qt.DisplayRole) == 'Young' else False
    return QSqlQueryModel.data(self, item, role)

then all the rows turn yellow.

What gives? Will anyone help me understand?

N.B. I'm aware that a non-empty python string will be equivalent to True

N.B. I can replicate the desired behaviour by adding another column to the SQL query (using CASE WHEN etc.) and then using setColumnHidden(col, True) to hide the test column.

Continuing the example you wrote, assume I wanted to test `lastname == "Young"` — Alan, May 22 '17 at 20:11

score 2 · Accepted Answer · answered May 22 '17 at 20:16

2

You should check the condition inside if role == Qt.BackgroundRole

def data(self, item, role):
    if role == Qt.BackgroundRole:
        if QSqlQueryModel.data(self, self.index(item.row(), 2), Qt.DisplayRole) == "Young":
            return QBrush(Qt.yellow)
    if role == Qt.DisplayRole:
        if item.column() == 3:
            return True if QSqlQueryModel.data(self, item, Qt.DisplayRole) == 1 else False
    return QSqlQueryModel.data(self, item, role)

answered May 22 '17 at 20:16

eyllanesc

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Hi @eyllanesc, I know it is an old subject, but just a quick question.I see you are creating a custom class, is this a requirement? That is every time we use roles do we need to subclass or can we just create a method inside or current class?Hope my question makes sense... – Heliomaster Nov 02 '18 at 09:47
@Heliomaster I do not understand you, explain yourself better. – eyllanesc Nov 02 '18 at 13:04
Hi @eyllanesc, thanks for coming back to me. My question is lets say I have my main class like so: `class MainWindow(QMainWindow, Lmt.Ui_MainWindow): def __init__(self, parent=None): super(MainWindow, self).__init__(parent) self.setupUi(self) self.LmtDb = LmtDataBase()` etc... could i add the data method inside this one or do I have to create a custom class and the work with roles inside this one. Hope this makes more sense... – Heliomaster Nov 03 '18 at 15:18
@Heliomaster okay, I understand what you point out, I gave the solution in a context but I see that it is inappropriate for your case, when you have time I will show you another option more simple and adaptable for your case with the help of a delegate. – eyllanesc Nov 03 '18 at 17:06
Thanks @eyllanesc. Very much willing to see how you do it. On a side note great job with your posts in general ,i’ve used a few of your examples on other subjects and they are always clear, concise and well documented. That’s what stack overflow is all about.... – Heliomaster Nov 04 '18 at 18:00
how to color only if clicked on the row cell – Madan Dec 09 '22 at 03:49

PyQt Tableview background color based on text value rather than True or False

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