Setting NSView readonly-property tag on subclass

Question

I have a class derived from NSView. NSView has a declaration

@property (readonly) NSInteger tag;

How can I set tag property to some value in my subclass? I tried following in my header file

@property(readwrite, assign) NSInteger tag;

Then in implementation I have

@dynamic tag
...
- (void)setTag:(NSInteger)newTag
{
    _tag = newTag;
}

This does not compile, I get 'Use of undeclared identifier: '_tag'. How can I set tag to a value?

score 1 · Accepted Answer · answered Nov 24 '15 at 09:56

I think the issue you're hitting is that _tag doesn't exist in the context where you're trying to set it, but if you use @synthesize like this:

#import <Cocoa/Cocoa.h>

@interface SOView : NSView

@property (readwrite) NSInteger tag;

@end


@implementation SOView

@synthesize tag = _tag;

- (void)awakeFromNib
{
    self.tag = 25;
}

@end

I tried this out in my own tiny test project and it worked perfectly fine.

Setting NSView readonly-property tag on subclass

1 Answers1