[PyQt] Interfacing with binary files: QDataStream issue

[Elvis Stansvik]

Den 19 juni 2017 9:09 em skrev "Christopher Probst" <
christop.probst at gmail.com>:
>
> Hi,
>
> I am exploring interfacing of files with QDataStream. But it does not
seem to work. To write to a file I do this:
>
>
> file = QFile("file.dat")
> color = QColor(Qt.red)
>
> if file.open(QIODevice.WriteOnly):
>  out = QDataStream(file)
>  out << color
>  file.flush()
>  file.close()
>
> It looks as if that the data gets written to the file. It is the reading
where there is a problem:
>
> file = QFile("file.dat")
> color = QVariant()
>
>
> if file.open(QIODevice.ReadOnly):
>  out = QDataStream(file)
>  out >> color

I haven't used QDataStream with PyQt, but this looks strange to me: How
will it know that it's a QColor you want to deserialise if color is a
QVariant? I think it needs to be a QColor for there to be any chance of
this working.

Hope that helps.

Elvis

>  print(color)
>  print(color.value())
>
> The output is:
>
> <PyQt5.QtCore.QVariant object at 0x7f2cdd556f28> None
>
> What am I doing wrong?
>
> Thanks, Christopher
>
>
>
>
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