How can I select the QGraphicView Item and change the properties

qt, c++

void Widget::on_btnCreateRect_clicked()
{

    QBrush blueBrush(Qt::green);
    QPen blackPen(Qt::black);
    blackPen.setWidth(2);

    rect = ui->graphicsView->scene()->addRect(-10,-10,250,100,blackPen);
    rect->setFlag(QGraphicsItem::ItemIsMovable, true);
}

Рекомендуємо хостинг TIMEWEB

Стабільний хостинг, на якому розміщується соціальна мережа EVILEG. Для проектів на Django радимо VDS хостинг.

It is very big question.
First I give You idea, from that You can start, but some example I can write to you on weekend only.

Ok I'll check it sir,If you can please do article(tutorial) about this,Its really useful.Thank you
if you can give me some sample code when you free.thanks again

I found my old project, where I made simple Vector Editor. I wrote article about this editor and you will find link to project.
You can research it. In this project You will see, why I said your question is very big.

And It will be very cool, if have oportunities to share this article in some socials networks. Thanks.

Thank you very much sir,My next problem was how re - size the QGraphicViewItem (such as rectangle) using mouse,I think your project also have that function,thanks again :)

You are correct sir, this is a big question,most part of your solution I can't understand.If you can please explain your project sir.If you can  please explain your code with each classes or please make some video tutorial with basic example,thank you

https://evileg.com/post/291/

I posted it here sir