draggingEntered not called - macos

Question

I have an NSBox subclass called dragBox. I want to be able to drag it around a canvas. The code is as follows:
-(void) awakeFromNib
{
[[self superview] registerForDraggedTypes:[NSArray arrayWithObject:NSFilenamesPboardType]];
}
-(void) mouseDown:(NSEvent *)theEvent
{
[self dragImage:[[NSImage alloc] initWithContentsOfFile:#"/Users/bruce/Desktop/Untitled-1.png"] at:NSMakePoint(32, 32) offset:NSMakeSize(0,0) event:theEvent pasteboard:[NSPasteboard pasteboardWithName:NSDragPboard] source:self slideBack:YES];
}
-(NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender // validate
{
NSLog(#"Updated");
return [sender draggingSourceOperationMask];
}
-(NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
NSLog(#"Drag Entered");
return [sender draggingSourceOperationMask];
}
- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
NSLog(#"Move Box");
[self setFrameOrigin:[sender draggingLocation]];
return YES;
}
-(BOOL) prepareForDragOperation:(id<NSDraggingInfo>)sender
{NSLog(#"Prepared");
return YES;
}
Why isn't dragEntered being called? I have tried to use all the pboard types and such. Nothing seems to work. I have also changed the registerForDraggedTypes to just work off of the [self] view. The box is a subview of a canvas.
Bruce

Answer 1

I found that awakeFromNib was the wrong place to put my registerForDragTypes call since I am programmatically adding my view (i.e. not adding it via a Nib). I had to put the call into initWithFrame:
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self registerForDraggedTypes: [NSArray arrayWithObjects:NSTIFFPboardType,NSFilenamesPboardType,nil]];
}
return self;
}

Answer 2

Bruce,
Your Code needs to be changed in the below way. I believe that view should be registered for drag types to make the method draggingEntered to get called.
#interface NSModifiedBox : NSBox
#end
#implementation NSModifiedBox
- (void)drawRect:(NSRect)dirtyRect
{
// Drawing code here.
[self registerForDraggedTypes:
[NSArray arrayWithObjects:NSTIFFPboardType,NSFilenamesPboardType,nil]];
[super drawRect:dirtyRect];
}
- (NSDragOperation)draggingEntered:(id )sender
{
if ((NSDragOperationGeneric & [sender draggingSourceOperationMask])
== NSDragOperationGeneric)
{
return NSDragOperationGeneric;
} // end if
// not a drag we can use
return NSDragOperationNone;
}
- (BOOL)prepareForDragOperation:(id )sender
{
return YES;
}
#end
Now Drag and Drop a NSBox on the Xib and the Modify the class of NSBox to NSModifiedBox.
Set a break point to the method "draggingEntered".
Now Drag a ".png" or ".gif" file and drop on the NSModifiedBox and you see the "draggingEntered" will get invoked
Or you can check by using NSLog as well inside a "draggingEntered".
Hope my answer will help you :)