From: "richard.j.dale@..." <richard.j.dale@...>
Date: 2006-11-21T03:25:05+09:00
Subject: Re: qtruby and the ListViewItemIterator

Vincent Fourmond wrote:
> Nigel Wilkinson wrote:
> > Hi folks
> >
> > I'm trying qtruby out and have struck an issue I can't conquer.
> >
> > I have a listview widget which is populated with listviewitems and want
> > to iterate through the whole lot.
> >
> > The code snippet is
> >
> > it = Qt::ListViewItemIterator.new(@listView)
> > puts it.operator++()
>
> > /mainform.ui.rb:33:in `method_missing': undefined method `operator' for
> > #<Qt::ListViewItemIterator:0xb6c08c24> (NoMethodError)
>
>   Well, the operator ++ is meant to be called directly ++ when written
> in C++. In ruby, however, that won't work as ++ is not an operator.
>   You might want to try (untested):
>
> p it.send(:'++')
That will nearly work, but the method is a C++ method in the Smoke
library, and so it is called 'operator++':

mardigras rdale 504% rbqt3api Qt::ListViewItemIterator |grep operator
        QListViewItem* QListViewItemIterator::operator*()
        QListViewItemIterator& QListViewItemIterator::operator++()
        const QListViewItemIterator
QListViewItemIterator::operator++(int)
        QListViewItemIterator& QListViewItemIterator::operator+=(int)
        QListViewItemIterator& QListViewItemIterator::operator--()
        const QListViewItemIterator
QListViewItemIterator::operator--(int)
        QListViewItemIterator& QListViewItemIterator::operator-=(int)
        QListViewItemIterator& QListViewItemIterator::operator=(const
QListViewItemI

Instead you need to do something like this:

p it.send("operator++".to_sym)

I've just added some each methods to various Qt3 QtRuby classes, and
made them enumerable, so you no longer need to use an external C++
style iterator with them. This is the comment from the ChangeLog:

	* Made Qt::ListView, Qt::ListViewItem, Qt::BoxLayout, Qt::HBoxLayout,
	  Qt::VBoxLayout and Qt::GridLayout Enumerable with implementations
	  of each() so they don't need to use the Qt External iterators like
	  Qt::LayoutIterator anymore. For instance:

		lv = Qt::ListView.new do
			["one", "two", "three", "four"].each do |label|
				Qt::ListViewItem.new(self, label, "zzz")
			end
		end

		lv.each do |item|
			p item.inspect
			pp item.inspect
		end

	* Add inspect() and pretty_print() methods to Qt::ListViewItem so that
	  they show the text of their columns

The improvements will be in the next release of Qt3 QtRuby.

-- Richard