Custom Delegate on Subclass of NSTableView

Question

Created Mar ’21

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I am updating and squashing bugs on a MacOS app I wrote several years ago. I have a subclass of NSTableView that I defined a delegate for that provides some convenience features for detecting user key and mouse input. The header file looks like this:

Code Block @class TKTableView;
// delegate protocol
@protocol TKTableViewDelegate <NSObject,NSTableViewDelegate> // <NSObject> because we need to use "respondsToSelector"
@optional
-(void)tableView:(NSTableView *)theTableView enterKeyPressedForRow:(NSInteger)theRow;
-(void)tableView:(NSTableView *)theTableView deleteKeyPressedForRow:(NSInteger)theRow;
-(void)tableView:(NSTableView *)theTableView didDoubleClickRow:(NSInteger)theRow;
-(NSMenu *)tableView:(NSTableView *)theTableView showContextualMenu:(NSEvent *)theEvent;
@end
@interface TKTableView : NSTableView
@property(nonatomic,assign) NSUInteger myRowHighlightStyle;
@property(nonatomic,readonly) id<TKTableViewDelegate> delegate;
-(void)doubleClickedRow:(id)sender;
@end

I'm getting warnings for...

Code Block @property(nonatomic,readonly) id<TKTableViewDelegate> delegate;

Warning 1: 'atomic' attribute on property 'delegate' does not match the property inherited from 'NSTableView'

Warning 2: Attribute 'readonly' of property 'delegate' restricts attribute 'readwrite' of property inherited from 'NSTableView'

I cobbled the delegate id property together via Google back when and cannot remember why I coded it as such. I know I can change to readwrite and atomic but I'm just not sure why it worked without warning in the past. What is the proper way to do this?

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Answer 1

Claude31 OP

Mar ’21

Did you try just to change as:

Code Block @property(nonatomic, readwrite) id<TKTableViewDelegate> delegate;

or even (as atomic is default value):

Code Block @property(readwrite) id<TKTableViewDelegate> delegate;

Get details here:
https://stackoverflow.com/questions/35198965/objective-c-property-attributes-best-practices

1

Answer 2

thinkcl OP

Mar ’21

@Claude31 thanks for the suggestion, it got me headed in the right direction. I did try both of those and the warnings kept pointing me to just use the default NSTableView attributes. I ended up using:

Code Block @property(assign) id<TKTableViewDelegate> delegate;

I can't remember why I originally set it up as nonatomic and readonly but it was probably some copy and paste from a tutorial or forum help.

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