Re: [Pyobjc-dev] Passing selectors as parameters

[Just v. R. <ju...@le...>]

Ronald Oussoren wrote:

> >     I have an NSListView whose double-click actions I would like to 
> > handle.  NSListView.setDoubleAction_( action ) requires a selector.  
> > My problem is that I'm not sure how to pass a method as a selector.  I 
> > would like to pass a class "instance" method (i.e. "def 
> > didDoubleClick( self ):") that belongs to the class I use as the 
> > listview's data source.  What is the correct way to do this?  I have 
> > tried a number of ways, and have searched for answers but have found 
> > no working solution yet.
> 
> You can use MyClass.didDoubleClick_ (e.g. a reference to an unbound
> method, although bound methods also work).

(Note that PyObjC then uses the method to get at the selector, ie. the method
name, it does not otherwise use the method.)

> Another option is the
> method name as a string ("didDoubleClick_").

Except you need to use the ObjC spelling then: "didDoubleClick:". I just
tried, the underscore notation doesn't work.

> You can use 'setTarget_(obj)' to set where the message should be send
> to.

Here's a snippet from the TableModel example (as of today, I checked in some
changes):

    def awakeFromNib(self):
        ...
        self.tableView.setTarget_(self)
        self.tableView.setDoubleAction_("doubleClick:")
        # this also works, but you still need to set the target:
        #self.tableView.setDoubleAction_(self.doubleClick_)
        return self

    def doubleClick_(self, sender):
        # double-clicking a column header causes clickedRow() to return -1
        print "doubleClick!", sender.clickedColumn(), sender.clickedRow()


> Note that the names of action methods should end with an underscore.

Just