Re: Drag and Drop with GObject introspection

[John Stowers <john stowers lists gmail com>]

On Mon, 2010-08-09 at 16:48 +0200, Mathias Brodala wrote:
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> Hi.
> 
> We recently did some experiments with porting PyGtk code to PyGi and
> stumbled over the Drag and Drop handling. In PyGtk nothing more than the
> following is required to allow a tree view to handle file drops:

I CC'd the python-hackers list which is where PyGi gets discussed.

John

> 
> > view = gtk.TreeView()
> >
> > view.drag_dest_set(
> >     gtk.DEST_DEFAULT_ALL,
> >     [('text/uri-list', 0, 0)],
> >     gtk.gdk.ACTION_COPY | gtk.gdk.ACTION_MOVE
> > )
> 
> With PyGi the equivalent function seems to be Gtk.drag_dest_set() which
> yields the following attempt:
> 
> > view = Gtk.TreeView()
> > target = Gtk.TargetEntry()
> > target.target = 'text/uri-list'
> > target.flags = 0
> > target.info = 0
> > 
> > Gtk.drag_dest_set(
> >     view,
> >     Gtk.DestDefaults.ALL,
> >     target,
> >     1,
> >     Gdk.DragAction.COPY | Gdk.DragAction.MOVE
> > )
> 
> However, the assignment of the target to the respective struct member
> yields the following error:
> 
> > RuntimeError: unable to set value for field
> 
> Why does the assignment to "target" fail whereas "flags" and "info" are
> fine?
> 
> The GTK docs describe the "targets" parameter of Gtk.drag_dest_set() as
> follows:
> 
> > a pointer to an array of GtkTargetEntrys indicating the drop types that
> > this widget will accept, or NULL.
> 
> However, there obviously are no pointers in Python. So how would one
> specify multiple targets here? Specify None upon Gtk.drag_dest_set() and
> separately modify the target list via Gtk.drag_dest_set_target_list()?
> This however also fails right at the Gtk.drag_dest_set() call with None
> as target and 0 as target count:
> 
> > TypeError: argument 2: Must be Gtk.TargetEntry, not NoneType
> 
> Simply specifying a list of targets also fails, no matter the content:
> 
> > TypeError: argument 2: Must be Gtk.TargetEntry, not list
> 
> Should I just file a bug report about Drag and Drop handling in PyGi in
> general?
> 
> 
> Regards, Mathias
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