How to write Tree model to QDataStream

[summit]

I have a QAbstractModel Tree structure i want to write all of my tree Items to the stream and load them back in the same hierarchy.

Please help me with any references or code that i can refer to .

[SGaist]

Hi,

Isn't that mostly the same question as here ?

[summit]

@SGaist this is more specific towards QDataStream.

[mrjj]

Hi
Well the first step is to implement
QDataStream &operator<<(QDataStream &, const QXxx &);
QDataStream &operator>>(QDataStream &, QXxx &);
for all classes involved.
Then you need to traverse the tree and output
each parent and its children. I think QList can be directly streamed if the class it holds has << >> overrides.

Most Qt types can be directly streamed so often the operator override is quite trivial and
only needs you to stream its class members.

please see
https://doc.qt.io/qt-5/qdatastream.html
and section
Reading and Writing Other Qt Classe

Also please note the easy to make mistake.
The operators << and >> takes reference to the type.
so when you stream a pointer,
you need to dereference it or it will just think "hey - its an int" and save the address.
so
stream << *someptr;
and not just plain
stream << someptr;
as that will just save its adress.

[mrjj]

Hi
There is also
https://github.com/VSRonin/Qt-Model-Serialisation
which might be useful if using a QAbstractItemModel model.

[summit]

@mrjj Thank you very much this is indeed very helpful