ComboBox of CheckBoxes?

Question

I am trying to make the items in a ComboBox checkable. I tried this:

http://programmingexamples.net/wiki/Qt/ModelView/ComboBoxOfCheckBoxes

where

Answer 1

I have a little addition.

If one compiles the skyhisi's code then the combobox on Mac OS X doesn't look as combobox with native checkboxes. You can see it on the screenshot.

Tested with qt-4.8.5 and 5.1.1.

It seems like Qt draws these controls by itself. Our team has found the following workaround by pure accident. You can subclass QStyledItemDelegate and reimplement paint() this way:

void SubclassOfQStyledItemDelegate::paint(QPainter * painter_, const QStyleOptionViewItem & option_, const QModelIndex & index_) const
{
    QStyleOptionViewItem & refToNonConstOption = const_cast(option_);
    refToNonConstOption.showDecorationSelected = false;
    //refToNonConstOption.state &= ~QStyle::State_HasFocus & ~QStyle::State_MouseOver;

    QStyledItemDelegate::paint(painter_, refToNonConstOption, index_);
}

You can then set this delegate to the combo box by adding the following lines to skyhisi's code:

SubclassOfQStyledItemDelegate *delegate = new SubclassOfQStyledItemDelegate(this);
combo->setItemDelegate(delegate);

The comboBox installed with this delegate looks the following way:

On Windows there may be a different issue: text of the checkBoxes has sticked background or dotted border around an item:

To change this appearance one can add the following line to the overridden paint just before the line QStyledItemDelegate::paint(painter_, refToNonConstOption, index_) (in the code sample this line was commented):

refToNonConstOption.state &= ~QStyle::State_HasFocus & ~QStyle::State_MouseOver;

Result: