QGraphicsSceneTextItem delete old text

Question

What I want to do is to delete or update the text value of the QGraphicsSimpleTextItem that i added to a QGraphicsItem,but for a certain cause the text do not update but it's acumulated in the item created.this is what i have done for now :

void DiagramItem::mouseDoubleClickEvent( QGraphicsSceneMouseEvent* event )
{
    if (event->button() != Qt::LeftButton)
    {
        return;
    }

    Dialog *mydiag = new Dialog();
    mydiag->show();
    if(mydiag->exec())
    {
        QString tx = mydiag->getname();
        txt = new QGraphicsSimpleTextItem;
        txt->setText(tx);
        txt->setParentItem(this);
    }
}

It looks like you're creating new text item every time. You need to keep a pointer to added text item and use it to update text. — Pavel Strakhov, Jun 04 '15 at 20:51

score 0 · Answer 1 · answered Jun 06 '15 at 14:18

Maybe you just need to eliminate two rows from your code:

QString tx = mydiag->getname();
// txt = new QGraphicsSimpleTextItem;
txt->setText(tx);
// txt->setParentItem(this);

So you won't create new items all the time.

But after this you can remove one more line:

// QString tx = mydiag->getname();
// txt = new QGraphicsSimpleTextItem;
txt->setText( mydiag->getname() );
// txt->setParentItem(this);

Do you initialize the txt in class constructor ? If yes than the previous code will be okay, but if you don't than you may want to use this:

if ( txt == nullptr )
{
    QString tx = mydiag->getname();
    txt = new QGraphicsSimpleTextItem;
    txt->setText(tx);
    // txt->setParentItem(this);
}

QGraphicsSceneTextItem delete old text

1 Answers1