Properly using QTableWidget and QTableWidgetItem

I am having a QMap through which I iterate. I would like to display the keys and values in my QTableWidget.

Code:

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int counter=0;
        QMapIterator<QChar,int> iter(ArithmeticCoding::letters_freq);
        while(iter.hasNext()){
            iter.next();
            QTableWidgetItem *item0=new QTableWidgetItem(iter.key());
            ui->table->setItem(counter,0,item0);
 
            QTableWidgetItem *item1=new QTableWidgetItem(iter.value());
            ui->table->setItem(counter,1,item1);
            counter++;
        }

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Of course here my pointers to QTableWidgetItem get lost resulting in random garbage in my table. What would be the proper way of using them? Should I save them to an additional array? That seems like an overhead to me.

What do you mean "get lost"? You allocate on the heap and the table take ownership of them. To use those later you use QTableWidget::item to get a pointer to the QTableWidgetItem in a row and column.

Anyway, do you actually get random (garbage) values in the table?

Zlatomir thanks for answering.

Your point about table taking ownership is correct, thanks for explaining. However, yes, I get random string garbage in in second cell (for iter.value()). Specifically, I get text from labels on my window instead of QMap values. Yes, strange. I've debugged and the values in QMap are correct so I was guessing something has to be wrong with pointers. A screenshot:

Attachment 8374



If I put in some string to second QTableWidgetItem it displays it well. Also, I've tested the iter.value() values (qDebug() << iter.value();) and they are correct. Maybe I have to cast int to String in some special way?

** MAJOR EDIT:
I was able to fill the second cell properly using
QTableWidgetItem *item1=new QTableWidgetItem(tr("%1").arg(iter.value()));

Why Did I have to do this it's still a mystery to me :)

You need to pass a QString there, use the static number to convert an int to QString and most likely you will need toInt too (to convert from QString to int).
so use this code:

Code:

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//...
 QTableWidgetItem *item1=new QTableWidgetItem( QString::number(iter.value()) );

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The problem seems to be that integet, because the QTableWidget has an constructor that takes an int as some "type" (i don't know what that means): doc link

Thanks, this also worked!