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-   -   Custom NSCell drawWithFrame:inView method not getting invoked in OSX 10.8 (http://www.mac-forums.com/forums/os-x-development-darwin/309046-custom-nscell-drawwithframe-inview-method-not-getting-invoked-osx-10-8-a.html)

mriganka 02-27-2014 04:00 AM

Custom NSCell drawWithFrame:inView method not getting invoked in OSX 10.8
 
I have an application where I have defined a custom cell and have overridden the method - (void) drawWithFrame:inView:

This method was drawing my custom cells without any problems as long as I was building my app using Xcode 3.2 on OS X 10.6 or older.

Now I am attempting to migrate the code to build with Xcode 4+ on OS X 10.8. And what I have found out is that my custom cell is not getting drawn anymore. After putting break points and running the app through the debugger, I realized that the overridden - (void) drawWithFrame:inView: method of the custom cell is not getting invoked at all.

My questions are:

1) What is it that makes this method to not invoke at all on OS X 10.8, while it gets invoked and works perfectly fine on OS X 10.6 or older?

2) What alternative do I have to fix this issue?

Thanks, Mriganka

Mark FX 02-28-2014 04:43 PM

Apple's documentation advises not to invoke drawWithFrame:inView in you're own subclasses, but advises people to use the drawInteriorWithFrame:inView: method instead.

The documentation for the latest implementation of the NSCell class is listed below.

https://developer.apple.com/library/...hFrame:inView:

The reason it's not working in the later OSX versions, is because this particular NSCell method has been changed in the way it's implemented.
Once upon time this method used to be named drawWithFrameInView:, but that version has been deprecated now.

Regards Mark

mriganka 02-28-2014 06:29 PM

According to the documentation, drawWithFrame:inView: invokes drawInteriorWithFrame:inView: after it draws the cell's border.

I tried overriding drawInteriorWithFrame:inView: in my code. That doesn't get invoked either.

Mark FX 03-01-2014 02:49 PM

I was reading the drawInteriorWithFrame:inView: method description in the documentation, listed below, and thats where it reccomends not using the drawWithFrame:inView: method,
but if neither method is getting called then it's irrelevant anyway.

Quote:

drawInteriorWithFrame:inView:
Draws the interior portion of the receiver, which includes the image or text portion but does not include the border.

- (void)drawInteriorWithFrame:(NSRect)cellFrame inView:(NSView *)controlView
Parameters
cellFrame
The bounding rectangle of the receiver, or a portion of the bounding rectangle.
controlView
The control that manages the cell.
Discussion
Text-type NSCell objects display their contents in a rectangle slightly inset from cellFrame using a global NSText object. Image-type NSCell objects display their contents centered within cellFrame. If the proper attributes are set, this method also displays the dotted-line rectangle to indicate if the control is the first responder and highlights the cell. This method is invoked from the drawCellInside: method of NSControl to visually update what the cell displays when its contents change. The drawing done by the NSCell implementation is minimal and becomes more complex in objects such as NSButtonCell and NSSliderCell.

This method draws the cell in the currently focused view, which can be different from the controlView passed in. Taking advantage of this is not recommended.

Subclasses often override this method to provide more sophisticated drawing of cell contents. Because drawWithFrame:inView: invokes drawInteriorWithFrame:inView: after it draws the cell's border, do not invoke drawWithFrame:inView: in your override implementation.

Availability
Available in OS X v10.0 and later.
See Also
isHighlighted
setShowsFirstResponder:
Declared In
NSCell.h
If neither method is getting called then you need to test that your NSCell subclass has been initialized properly, perhaps by checking one of it's properties in the log.

Regards Mark


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