writeRowsWithIndexes is not calling in NSTableView with custom cell

Question

I have implemented following delegate to support drag n drop in NSTableView. Delegates validateDrop and acceptDrop are called and I'm able to drag and drop content from Finder to NSTableView however writeRowsWithIndexes is not called when I tried to drag items from NSTableView and drop to Finder.

- (BOOL)tableView:(NSTableView *)aTableView writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard *)pboard
{
  NSLog(@"writeRowsWithIndexes");
  return YES;
}

- (NSDragOperation)tableView:(NSTableView *)aTableView validateDrop:(id < NSDraggingInfo >)info proposedRow:(NSInteger)row proposedDropOperation:(NSTableViewDropOperation)operation
{
 NSLog(@"validateDrop");
 return NSDragOperationCopy;
}

- (BOOL)tableView:(NSTableView *)aTableView acceptDrop:(id < NSDraggingInfo >)info row:(NSInteger)row dropOperation:(NSTableViewDropOperation)operation
{
NSLog(@"acceptDrop"); 
return YES;
}

I have registered dragging types as

//Registering dragged Types
[tableView registerForDraggedTypes:[NSArray arrayWithObjects:NSFilenamesPboardType, nil]];
//To support across application passing NO
[tableView setDraggingSourceOperationMask:NSDragOperationCopy forLocal:NO];
//Don't want any highlight selection on drop
[tableView setDraggingDestinationFeedbackStyle:NSTableViewDraggingDestinationFeedbackStyleNone];

Drag is not initiating in my NSTableView, Can anybody tell me what could be the possible reasons? I have custom cell in the TableView and also set delegate and datasource properly.

1. On hit & trial I identified that dragging is only starting form cell separator, not on the cell content area. 2. Dragging image delegate is also not called - (NSImage *)dragImageForRowsWithIndexes:(NSIndexSet *)dragRows tableColumns:(NSArray *)tableColumns event:(NSEvent *)dragEvent offset:(NSPointPointer)dragImageOffset — Anni S

Anni S Anni S · Accepted Answer · 2014-09-10T13:09:45

I found the cause, it was due to Custom cell. I had subclassed my custom cell from NSButtonCell. Dragging is not working on button cell because buttons are not meant for dragging, they are meant for illuminating. I resolved the issue by sub classing my custom cell from NSActionCell.

Found in the below post: NSTableView Drag and Drop not working

writeRowsWithIndexes is not calling in NSTableView with custom cell

1 Answers