From: Stefano Crocco <stefano.crocco@...>
Date: 2012-09-01T21:13:28+09:00
Subject: Re: Qt signals driving me crazy

On Saturday 01 September 2012 Damjan Rems wrote
> Stefano was right. It works now. I must have lost my nerves somewhere in
> beetween ;-( The problem is that all three declarations must be the
> same:
> 
> slots 'nitem_clicked(QTreeWidgetItem*, int)'
> 
> connect(self, SIGNAL('itemActivated( QTreeWidgetItem*, int )'),
> self, SLOT('nitem_clicked(QTreeWidgetItem*, int)'))
> 
> Thanks guys.
> ----------------------
> 
> Now I have another problem. You can add text and icons to
> Qt::TreeWidgetItem.
> 
>   item = Qt::TreeWidgetItem.new
>   item.setText(0,'Test')
>   item.setIcon(0, Qt::Icon.new('pics/test.png') )
> 
> But I would like to add an object. There is a method
> QTreeWidgetItem::setData ( int column, int role, const QVariant & value
> )
> 
>   If I use item.setData(0, Qt::UserRole, some_object) I get
>      method_missing': undefined method `setData ...
> 
> which usually means that one of data type is not valid. Is there another
> way to add object pointer to QTreeWidgetItem.
> 
> by
> TheR
> 
> --
> Posted via http://www.ruby-forum.com/.

setData requires s Qt::Variant as last argument, not a ruby object. In theory, 
with sufficiently recent version of QtRuby, you should be able to create a 
Qt::Variant from any ruby object using

Qt::Variant.from_value my_obj

When I tried it, however, I found out that it sometimes caused crashes. There 
should also be another way to do so, which I haven't tried. Look at the first 
example at 
http://techbase.kde.org/Development/Languages/Ruby#Emitting_Ruby_Classes

If these methods don't work for you, your only option is to somehow create a 
string or number or something else which you can put in a Qt::Variant and 
which allows you to identify the object (the object_id of the object itself 
could be a good candidate).

I hope this helps

Stefano