Set default alignment for cells in QTableWidget

Question

I know you can set the alignment for each item using:

TableWidget->item(0,0)->setTextAlignment(Qt::AlignLeft);

However I would like to set a default alignment for all the cells in order to do not have to set it every time I create a new item. Is it possible?

score 27 · Accepted Answer · answered Apr 05 '13 at 08:09

Yes it is possible. But you need to understand you are not modifying a property of the table widget, but a property of the table widget item. First create your own item, and set it up as you want

 QTableWidgetItem * protoitem = new QTableWidgetItem();
 protoitem->setTextAlignment(Qt::AlignLeft);
 etc...

Then each time you want to create a new item rather than using the constructor you use

 QTableWidgetItem * newitem = protoitem->clone();
 tableWidget->setItem(0,0, newitem);

Another alternative to clone (untested) is to set a prototype on your tablewidget

QTableWidget::setItemPrototype ( const QTableWidgetItem * item )

This last one can be more appropriate if you are using a Ui or if the item is editable.

score 10 · Answer 2 · answered Apr 05 '13 at 08:21

I don't think there is an existing method for this, but here's two approaches that work:

1.) Subclass QTableWidgetItem

MyTableWidgetItem::MyTableWidgetItem() :
    QTableWidgetItem()
{
    setTextAlignment( Qt::AlignLeft );
}

However, this is probably a bit overkill for just a single setting + you might want to overload all four constructors of QTableWidgetItem.

2.) Another approach is using a factory instead of calling new:
Note: The linked article talks about unit testing, but there are many more advantages by doing that.

QTableWidgetItem* MyTableWidgetFactory::createTableWidgetItem( const QString& text ) const
{
    QTableWidgetItem* item = new QTableWidgetItem( text );
    item->setTextAlignment( Qt::AlignLeft );
    return item;
}

Then instead of

QTableWidgetItem* myItem = new QTableWidgetItem( "foo" );
item->setTextAlignment( Qt::AlignLeft );

you can do

QTableWidgetItem* myItem = myFactory->createTableWidgetItem( "foo" );

where myFactory is an object of MyTableWidgetFactory.

score 0 · Answer 3 · answered Jul 15 '23 at 06:42

If you're using delegates for cells, rows or columns, you'd be subclassing QStyledItemDelegate; it has a method initStyleOption which can be used to set style options for all cells using your delegate.

void MyItemDelegate::initStyleOption(QStyleOptionViewItem *option,
                                     const QModelIndex &index) const override {
  // call base class implementation to set things up as default
  QStyledItemDelegate::initStyleOption(option, index);

  // override just the style options you want later
  option->displayAlignment = Qt::AlignCenter;
}

It's more elegant and less cumbersome unlike when working with QTableWidgetItems.

Set default alignment for cells in QTableWidget

3 Answers3

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