From: Stefano Crocco <stefano.crocco@...>
Date: 2008-03-02T22:26:44+09:00
Subject: Re: Qt-question: How to react on a click on a table-cell?

Alle Sunday 02 March 2008, Adna rim ha scritto:
> Hi,
> I want to achieve that if someone clicks on a cell in a Qt::Table
> something happens. This is my code:
>
> #!/usr/bin/env ruby
> require 'Qt'
>
> class MyWidget < Qt::Widget
>         slots 'but_clie()'
>
>         def initialize(parent=nil)
>                 super(parent)
>                 @table = Qt::Table.new(10,10,self)
>                 connect(@table,SIGNAL('clicked()'),self,SLOT('but_clie
> ()'))
>         end
>
>         def but_clie
>                 puts "clicked"
>         end
> end
>
>
> app = Qt::Application.new(ARGV)
> mw = MyWidget.new
> app.setMainWidget(mw)
> mw.show
> app.exec()
> # done
>
> But If I start the app I always get this error:
> QObject::connect: No such signal Qt::Table::clicked()
> QObject::connect:  (sender name:   'unnamed')
> QObject::connect:  (receiver name: 'unnamed')
>
> But the Qt3 doc tells me that it definitivly has the signal clicked() ?
>
> What am I doing wrong here?
>
> greets

If you look at the documentation for QTable, you'll see that it has indeed a
clicked(), but that it takes four parameters (row, col, button and mousePos). 
So, the correct way to connect signal and slot is:

connect(@table, SIGNAL('clicked(int, int, int, QPoint&'), self,
  SLOT('but_clie()'))

Note that, even if the code above works, your slot won't receive none of the
four parameters. If you want to receive them, you should declare the slot as:

slots 'but_clie(int,int,int,QPoint&)'

and connect it with

connect(@table, SIGNAL('clicked(int, int, int, QPoint&'), self,
  SLOT('but_clie(int,int,int,QPoint&)'))

Often, when qtruby says there's not a method with a certain name, the truth is 
that such a method exists, but it takes different parameters from the ones you 
used.

Disclaimer: all this code hasn't been tested, because I'm not using Qt3
anymore.

I hope this helps

Stefano