[MacRuby-devel] HotCocoa table_view and the doubleAction

[John Shea]

Thanks Brian!

that cleared up all the remaining puzzles !

I must admit i just assumed that the data source and delegate were  
married together in some way in hotcocoa - now that you have given me  
a much better background it all now makes sense.

And thanks for the link.

Cheers,
John


On Apr 1, 2009, at 8:07 PM, Brian Chapados wrote:

> You might have already figured this out, but in case it helps...
>
> Be careful not to confuse the TableView delegate with the DataSource  
> delegate.
> Check out the TableView programming guide:
> http://developer.apple.com/documentation/Cocoa/Conceptual/TableView/TableView.html
>
> You can use two different sets of delegate messages to customize an
> NSTableView.  The datasource delegate methods get called in order to
> populate the table with data. The TableView delegate methods get
> called in response to user-generated events.
>
> The DataSource informal protocol:
> http://developer.apple.com/documentation/Cocoa/Reference/ApplicationKit/Protocols/NSTableDataSource_Protocol/Reference/Reference.html#/ 
> /apple_ref/occ/cat/NSTableDataSource
>
> delegate methods specific for a TableView:
> http://developer.apple.com/documentation/Cocoa/Conceptual/TableView/Tasks/UsingTableDelegate.html#/ 
> /apple_ref/doc/uid/20000116-CJBDHFIC
>
> Your tableview delegate can also respond to delegate messages for
> NSControl and NSView (its superclasses).
>
> In your list below,
>> #is not delegated to
>>  def tableView(tv, setObjectValue:anObject, forTableColumn:col,  
>> row:row)
>>    NSLog("tableView setObject")
>>    #edit data here
>>  end
>> #is not delegated to
>>  def numberOfRowsInTableView(tv)
>>    NSLog("numberOfRowsInTableView")
>>    0 #test 0
>>  end
>> #is not delegated to
>>  def tableView(tv, objectValueForTableColumn:col, row:row)
>>    NSLog("objectValueForTableColumn")
>>    val = "richard"
>>  end
>
> These methods are sent to the 'dataSource' delegate, not the
> 'delegate' (view delegate).  In order for your dataSource delegate
> methods to be called, you need to either:
>
> 1. Define the methods in a separate class, and assign an instance of
> that class as:
> @tableView.dataSource = myDataSource
>
> 2. Define the methods in your TableView Controller class, set the
> dataSource delegate to self:
> @tableView.dataSource = self
>
> You _must_ set the tableView delegate in order to receive the
> messages, even if you have everything in one class and you just want
> to set them to 'self'.
>
> For simple cases, you can implement both the 'dataSource' and view
> 'delegate' classes in your TableView controller and set both delegates
> to self.  For an example of this, see the FlickrDemo example app in
> macruby-examples dir.
>
> Also, since it was mentioned, you should be able to leave the 'target'
> property unset (or set it to nil).  In cocoa, nil targeted actions do
> _not_ go into the void.  Instead, they sent are passed along the
> responder chain so that the next appropriate control can handle the
> message. This is useful for when you want to the same action to be
> performed as a result of different inputs (i.e. menu, button or click
> in row, ect..).  You can just define the action methods in a class
> that is part of the responder chain and send a nil targeted actions
> from your controls.
>
> There is must-listen Mac-Developer Network podcast interview with
> Aaron Hillegass on the Responder Chain:
> http://www.mac-developer-network.com/shows/podcasts/lnc/lnc009/
>
> Brian
>
> 2009/4/1 John Shea <johnmacshea at gmail.com>:
>> Hi Dave,
>> thanks for your answer.
>>
>> On Apr 1, 2009, at 14:39 , Dave Baldwin wrote:
>>
>> I haven't had any problems using delegate methods. For example I do:
>> @tableView.delegate = self
>> and define a delegate method:
>> def tableView (table, shouldEditTableColumn: c, row: r)
>> false
>> end
>>
>> Thats the first thing I tried - but for the tableView(table,  
>> setObjectValue
>> .. method which was not delegated to.
>> Unfortunately as it was the first one i tried (because i wanted to  
>> edit
>> table fields) -  that sent me on a wild goose chase trying to  
>> figure out why
>> the delegate was not working as it was in all of my non-hotcocoa  
>> code.
>> So thanks for pointing out that some of them are actually delegated  
>> to.
>> For me:
>>
>>   #works
>>   def controlTextDidChange(notification)
>>       NSLog("controlTextDidChange #{notification.object}")
>>       NSLog(@mv_table_view.selectedRow.to_s)
>>   end
>>
>>   #works
>>   def tableView(tv, willDisplayCell:cell, forTableColumn:col,  
>> row:the_row)
>>    NSLog("willDisplayCell")
>>   end
>>   #works
>>   def tableViewSelectionDidChange(notification)
>>     NSLog("tableViewSelectionDidChange")
>>   end
>> #is not delegated to
>>   def tableView(tv, setObjectValue:anObject, forTableColumn:col,  
>> row:row)
>>     NSLog("tableView setObject")
>>     #edit data here
>>   end
>> #is not delegated to
>>   def numberOfRowsInTableView(tv)
>>     NSLog("numberOfRowsInTableView")
>>     0 #test 0
>>   end
>> #is not delegated to
>>   def tableView(tv, objectValueForTableColumn:col, row:row)
>>     NSLog("objectValueForTableColumn")
>>     val = "richard"
>>   end
>>
>> I could probably do a work around with controlTextDidChange - but  
>> it seems a
>> bit dodgy.
>> Or another option would be to edit not within the table, but in  
>> another
>> form.
>> I suppose there is some simple explanation - but I am missing it  
>> for the
>> moment.
>> Cheers,
>> J
>>
>>
>>
>>
>>
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