NSOutlineView Drag-n-Drop

Question

In my application, NSOutlineView used as below, 1 -- Using CustomOutlineView because i want to control NSOutlineView Background,

2 -- Using CustomeCell, becuase i need to have customize Cell

Header File : MyListView.h

/* 
 MyUICustomView is the Subclass from NSView and this is i need to have 
 for some other my application purpose 
*/
@interface MyListView : MyUICustomView<NSOutlineViewDataSource> 
{
      // MyCustomOutlineview because, i need to override DrawRect Method to have   
      //   customized background 
      MyCustomOutlineView *pMyOutlineView;

}

@property(nonatomic,retain)MyCustomOutlineView *pMyOutlineView;

and also i should be able to drag-n-drop within Outline view, for having drag-n-drop i have done following,

  -(void)InitOutlineView{
        // Creating outline view 
        NSRect          scrollFrame = [self bounds];
    NSScrollView*   scrollView  = [[[NSScrollView alloc] initWithFrame:scrollFrame] autorelease];

    [scrollView setBorderType:NSNoBorder];
    [scrollView setHasVerticalScroller:YES];
    [scrollView setHasHorizontalScroller:NO];
    [scrollView setAutohidesScrollers:YES];
    [scrollView setDrawsBackground: NO];

    NSRect          clipViewBounds  = [[scrollView contentView] bounds];
    pMyOutlineView       = [[[MyCustomOutlineView alloc] initWithFrame:clipViewBounds] autorelease];


    NSTableColumn*  firstColumn     = [[[NSTableColumn alloc] initWithIdentifier:@"firstColumn"] autorelease];
#ifdef ENABLE_CUSTOM_CELL
        // Becuase cell should have Image, Header Info and brief detail in small font, 
        // so i need to have custom cell 
    ImageTextCell *pCell = [[ImageTextCell alloc]init];
    [firstColumn setDataCell:pCell];
        // SO i can fill the data 
    [pCell setDataDelegate:self];
# endif

        [pMyOutlineView setDataSource:self];
        /* This is to tell MyCustomOutlineView to handle the context menu */
    [pMyOutlineView setDataDelegate:self];
        [scrollView setDocumentView:pCTOutlineView];

        [pMyOutlineView  addTableColumn:firstColumn];
        [pMyOutlineView registerForDraggedTypes:
         [NSArray arrayWithObjects:OutlinePrivateTableViewDataType,nil]];

        [pMyOutlineView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:YES];**

    }

and to Support drag-n-drop Implemented following method

        - (BOOL)outlineView:(NSOutlineView *)outlineView writeItems:(NSArray *)items toPasteboard:(NSPasteboard *)pboard{
        NSData *data = [NSKeyedArchiver archivedDataWithRootObject:items];
        [pboard declareTypes:[NSArray arrayWithObject:OutlinePrivateTableViewDataType] owner:self];
        [pboard setData:data forType:OutlinePrivateTableViewDataType];
        return YES;

    }


    - (NSDragOperation)outlineView:(NSOutlineView *)outlineView validateDrop:(id < NSDraggingInfo >)info proposedItem:(id)item proposedChildIndex:(NSInteger)index{
    // Add code here to validate the drop

    NSLog(@"validate Drop");
    return NSDragOperationEvery;
}

        - (BOOL)outlineView:(NSOutlineView *)outlineView acceptDrop:(id < NSDraggingInfo >)info item:(id)item childIndex:(NSInteger)index{
          NSLog(@"validate Drop");
    }

but still when i try to drag the row of NSOutlineView nothing is happening, even i tried to debug via NSLog but i couldn't see any log from above function, Am i missing any important method ? to support Drag-n-drop

Answer 1

HI, FInally got able to rid of this, The problem is

[firstColumn setWidth:25];

So drag was working only upto 25 pixel form the left, and i commented this, then its working time, but strange to see, my outline view has only one column , for drawing, its not checking the restriction but for drag-n-drop its checking,

Thanks Joshua

Answer 2

Based on your code, it looks like you're not returning anything for the ...writeItems... method. This method is supposed to return a BOOL (whether the items were successfully written or you're denying the drag). Returning nothing should be giving you a compiler warning ...