pyobjc-dev

[Pyobjc-dev] NSTableView and Drag and Drop

[John S. <jo...@sk...>]

Hi PyObjC list,

I have a table view that I'd like to add drag and drop support to. I  
borrowed a lot of code from the bookmarks example and some Objective-C  
examples I've found across the net (and I used  
tableView_writeRowsWithIndexes_toPasteboard_ rather than  
tableView_writeRows_toPasteboard_ since I read writeRows is  
deprecated). I've also modified it a little since my application is  
not document-based. Ideally the user would be able to reorder items in  
the table (I don't anticipate the need for copy and paste).  I have it  
almost working--I can drag an element, but on drop, I get the  
following error:

An unexpected error has occurred
(TypeError: 'NoneType' object is not iterable)

I've implemented the three methods I believe I'm supposed to implement  
for DND table support and I've declared a pasteboard type. I don't  
know if it's because the acceptDrop or validateDrop methods aren't  
working. Ideas?

My code is below:

"""
   ApplicationDelegate.py
   Controller class for the application
"""

from Foundation import *
from AppKit import *
from PyObjCTools import NibClassBuilder
import objc
from objc import YES, NO, IBOutlet, IBAction

from ApplicationModel import *

MovedRowsType = u"MOVED_ROWS_TYPE"

class ApplicationDelegate(NSObject):
   # Outlets
   arrayController = objc.IBOutlet()
   tableView = objc.IBOutlet()

   # Class methods
   def init(self):
     self = NSObject.init(self)
     return self

   def awakeFromNib(self):
     # register for drag and drop
     self.tableView.registerForDraggedTypes_([MovedRowsType])

   def tableView_writeRowsWithIndexes_toPasteboard_(self, tv,  
rowIndexes, pboard):
     typesArray = [MovedRowsType]
     data = NSKeyedArchiver.archivedDataWithRootObject_(rowIndexes)
     pboard.declareTypes_owner_(typesArray, self)
     #pboard.setData_forType_(typesArray, self)
     NSLog("boo-yeah")
     return YES

   def tableView_validateDrop_proposedRow_proposedDropOperation_(self,  
tv, info, row, op):
     dragOp =  NSDragOperationMove
     tv.setDropRow_dropOperation_(row, NSTableViewDropAbove)
     return dragOp

   def tableView_acceptDrop_row_dropOperation_(self, tv, info, row, op):
     if row < 0:
       row = 0

     if info.draggingSource() == self.tableView:
       rows =  
info.draggingPasteboard().propertyListForType_(MovedRowsType)
       indexSet = self.indexSetFromRows_(rows)
       self.moveObjectsInArrangedObjectsFromIndexes_toIndex_(indexSet,  
row)

       rowsAbove = self.rowsAboveRow_inIndexSet_(row, indexSet)
       aRange = NSMakeRange(row - rowsAbove, indexSet.count())
       indexSet = NSIndexSet.indexSetWithIndexesInRange_(aRange)
       self.arrayController.setSelectionIndexes_(indexSet)
       return YES
     return NO

   def moveObjectsInArrangedObjectsFromIndexes_toIndex_(self,  
indexSet, insertIndex):
     objects = self.arrayController.arrangedObjects()
     index = indexSet.lastIndex()
     aboveInsertIndexCount = 0
     removeIndex = 0
     while index != NSNotFound:
       if index >= insertIndex:
         removeIndex = index + aboveInsertIndexCount
         aboveInsertIndexCount += 1
       else:
         removeIndex = index
         insertIndex -= 1
       obj = objects.objectAtIndex_(removeIndex)
        
self.arrayController.removeObjectAtArrangedObjectIndex_(removeIndex)
       self.arrayController.insertObject_atArrangedObjectIndex_(obj,  
insertIndex)
       index = indexSet.indexLessThanIndex_(index)

   def indexSetFromRows_(self, rows):
     indexSet = NSMutableIndexSet.indexSet()
     for row in rows:
       indexSet.addIndex_(row)
     return indexSet

   def rowsAboveRow_inIndexSet_(self, row, indexSet):
     currentIndex = indexSet.firstIndex()
     i = 0
     while currentIndex != NSNotFound:
       if currentIndex < row:
         i += 1
     currentIndex = indexSet.indexGreaterThanIndex_(currentIndex)
     return i

Re: [Pyobjc-dev] NSTableView and Drag and Drop

[Michael M. <mic...@gm...>]

Hi John, from a quick peek at your code, it sounds like the 'rows'
argument in    indexSetFromRows_ is None, since it's trying to iterate
it.

And it looks like in tableView_writeRowsWithIndexes_toPasteboard_, you
declare the type but have commented out the setData call:

   def tableView_writeRowsWithIndexes_toPasteboard_(self, tv,
rowIndexes, pboard):
     typesArray = [MovedRowsType]
     data = NSKeyedArchiver.archivedDataWithRootObject_(rowIndexes)
     pboard.declareTypes_owner_(typesArray, self)
     #pboard.setData_forType_(typesArray, self)
     NSLog("boo-yeah")
     return YES

I'm guessing your call to setData_forType_ should look something more like this:
pboard.setData_forType_(data, MovedRowsType), and then when you ask
for the data later in acceptDrop:
rows = info.draggingPasteboard().propertyListForType_(MovedRowsType)

you should get something other than None.

HTH,
-mike


On Jan 24, 2008 2:51 PM, John Skidgel <jo...@sk...> wrote:
>
> Hi PyObjC list,
>
> I have a table view that I'd like to add drag and drop support to. I
> borrowed a lot of code from the bookmarks example and some Objective-C
> examples I've found across the net (and I used
> tableView_writeRowsWithIndexes_toPasteboard_ rather than
> tableView_writeRows_toPasteboard_ since I read writeRows is deprecated).
> I've also modified it a little since my application is not document-based.
> Ideally the user would be able to reorder items in the table (I don't
> anticipate the need for copy and paste).  I have it almost working--I can
> drag an element, but on drop, I get the following error:
>
> An unexpected error has occurred
> (TypeError: 'NoneType' object is not iterable)
>
> I've implemented the three methods I believe I'm supposed to implement for
> DND table support and I've declared a pasteboard type. I don't know if it's
> because the acceptDrop or validateDrop methods aren't working. Ideas?
>
> My code is below:
>
>
> """
>   ApplicationDelegate.py
>   Controller class for the application
> """
>
> from Foundation import *
> from AppKit import *
> from PyObjCTools import NibClassBuilder
> import objc
> from objc import YES, NO, IBOutlet, IBAction
>
> from ApplicationModel import *
>
> MovedRowsType = u"MOVED_ROWS_TYPE"
>
> class ApplicationDelegate(NSObject):
>   # Outlets
>   arrayController = objc.IBOutlet()
>   tableView = objc.IBOutlet()
>
>   # Class methods
>   def init(self):
>     self = NSObject.init(self)
>     return self
>
>   def awakeFromNib(self):
>     # register for drag and drop
>     self.tableView.registerForDraggedTypes_([MovedRowsType])
>
>   def tableView_writeRowsWithIndexes_toPasteboard_(self, tv, rowIndexes,
> pboard):
>     typesArray = [MovedRowsType]
>     data = NSKeyedArchiver.archivedDataWithRootObject_(rowIndexes)
>     pboard.declareTypes_owner_(typesArray, self)
>     #pboard.setData_forType_(typesArray, self)
>     NSLog("boo-yeah")
>     return YES
>
>   def tableView_validateDrop_proposedRow_proposedDropOperation_(self, tv,
> info, row, op):
>     dragOp =  NSDragOperationMove
>     tv.setDropRow_dropOperation_(row, NSTableViewDropAbove)
>     return dragOp
>
>   def tableView_acceptDrop_row_dropOperation_(self, tv, info, row, op):
>     if row < 0:
>       row = 0
>
>     if info.draggingSource() == self.tableView:
>       rows = info.draggingPasteboard().propertyListForType_(MovedRowsType)
>       indexSet = self.indexSetFromRows_(rows)
>       self.moveObjectsInArrangedObjectsFromIndexes_toIndex_(indexSet, row)
>
>       rowsAbove = self.rowsAboveRow_inIndexSet_(row, indexSet)
>       aRange = NSMakeRange(row - rowsAbove, indexSet.count())
>       indexSet = NSIndexSet.indexSetWithIndexesInRange_(aRange)
>       self.arrayController.setSelectionIndexes_(indexSet)
>       return YES
>     return NO
>
>   def moveObjectsInArrangedObjectsFromIndexes_toIndex_(self, indexSet,
> insertIndex):
>     objects = self.arrayController.arrangedObjects()
>     index = indexSet.lastIndex()
>     aboveInsertIndexCount = 0
>     removeIndex = 0
>     while index != NSNotFound:
>       if index >= insertIndex:
>         removeIndex = index + aboveInsertIndexCount
>         aboveInsertIndexCount += 1
>       else:
>         removeIndex = index
>         insertIndex -= 1
>       obj = objects.objectAtIndex_(removeIndex)
>       self.arrayController.removeObjectAtArrangedObjectIndex_(removeIndex)
>       self.arrayController.insertObject_atArrangedObjectIndex_(obj,
> insertIndex)
>       index = indexSet.indexLessThanIndex_(index)
>
>   def indexSetFromRows_(self, rows):
>     indexSet = NSMutableIndexSet.indexSet()
>     for row in rows:
>       indexSet.addIndex_(row)
>     return indexSet
>
>   def rowsAboveRow_inIndexSet_(self, row, indexSet):
>     currentIndex = indexSet.firstIndex()
>     i = 0
>     while currentIndex != NSNotFound:
>       if currentIndex < row:
>         i += 1
>     currentIndex = indexSet.indexGreaterThanIndex_(currentIndex)
>     return i
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-- 
Michael McCracken
UCSD CSE PhD Candidate
research: http://www.cse.ucsd.edu/~mmccrack/
misc: http://michael-mccracken.net/wp/