Issues with QStyledItemDelegate

superaga

Hi experts!

I searched for this topic in the forum and I didn't find it, so I'm creating this one.

I made a very simple custom widget (LED) that I tested and works fine:

Now, I'd like to make a custom dialog which uses this widget to show the values of my QAbstractTableModel.

From what I read, I think that I have to use the QStyledItemDelegate class.
Is this correct?
Assuming that "yes it is", I went through the Star Delegate Example.

I basically replicate the example, but when I run the code I suddenly discovered that the QTableView widget that I'm using doen't support the setItemDelegate.

Ok, then I replace it with the (used in the Star Delegate Example) QTableWidget widget which... doesn't support the setModel method. 🤦‍♂️

So before diving into the code etc, etc, is there someone that could please explain me the steps to achieve what I need and the classes to use?

As usual, many thanks to all! 🙇‍♂️

Kind regards,
AGA

JonB

@superaga
Yes, so LedDelegate is a class and you have to pass an instance. Hence the (admittedly cryptic) error message.

JoeCFD

@superaga
setItemDelegate(QAbstractItemDelegate *) is there.
https://doc.qt.io/qt-5.15/qtableview-members.html

your Qt version?

superaga

Hi @JoeCFD, many thanks for your quick reply!

I'm using the latest PyQt6 (6.4.2).
But you linked me the QAbstractItemView class, which I'm not directly using it.
Should I then replace my QtableView with this?

Thanks!
AGA

JoeCFD

@superaga https://doc.qt.io/qt-6/qtableview-members.html
it is there as well. QTableView is a subclass of QAbstractItemView.
What problem do you have when you call setItemDelegate?
setItemDelegate is supported in QTableView.

superaga

Hi @JoeCFD,

I've got this error:

In my view code table_data it is simply defined as:

self.table_data = QTableView()

Do I made some other mistake then?

Many thanks!
AGA

JonB

@superaga
Please prefer to paste code rather than screenshots.

What is the type of the value assigned to your LedDelegate?

superaga

Hi @JonB,

sorry, ok, I'll report the error code next time.

LedDelegate inherits the QStyledItemDelegate and it is defined as:

class LedDelegate(QStyledItemDelegate):
    def __init__(self, parent=None) -> None:
        super().__init__(parent)

    def paint(
        self, painter: QPainter, option: QStyleOptionViewItem, index: QModelIndex
    ) -> None:
        
        if index.column == 1:
            self.led_numeric = Led(index.data(), color=YELLOW)
        elif index.column == 2:
            self.led_bool_ok = Led(index.data(), color=GREEN)
        elif index.column == 3:
            self.led_bool_error = Led(index.data(), color=RED)
        else:
            QStyledItemDelegate.paint(self, painter, option, index)

    def sizeHint(self, option, index) -> QSize:
        if index.column()==1:
            self.led_numeric=Led(index.data(), color=YELLOW)
            return self.led_numeric.sizeHint()
        elif index.column()==2:
            self.led_bool_ok=Led(index.data(), color=GREEN)
            return self.led_bool_ok.sizeHint()
        elif index.column()==3:
            self.led_bool_error=Led(index.data(), color=RED)
            return self.led_bool_error.sizeHint()
        else:
            QStyledItemDelegate.sizeHint(self,option,index)

Which is basically the copy of the Star Delegate Example.

Thanks.

JonB

@superaga
Yes, so LedDelegate is a class and you have to pass an instance. Hence the (admittedly cryptic) error message.

superaga

Hi @JonB,

many thanks! Yes that solved the issue (kudos!).

Sorry, my bad 🤦‍♂️
I'm so "addicted" to these powerful syntax code analysis that, when they don't provide me the error, I think to something else... Anyway, yes the error message was to cryptic to understand the root cause...

Here the trivial solution... A couple of parenthesis () because it was a class, not a property!

...
view = MyView(model_table=model_table, model_list=model_list)
view.table_data.setItemDelegate(LedDelegate())
...

P.S. probably best to rename this topic from Custom widgets within Model/View to Issues with QStyledItemDelegate.
Also because I was thinking to use the first title for my next question 😅.
Is it ok? Or best is to find another topic title?

Many thanks! 🙏
AGA

JonB

@superaga
Yes, you have it right now. This is where Python only detects at runtime what a C++ compiler would reject at compile-time so it would have been clearer.

I wouldn't worry about your topic title, it's fine.