Objective-C Properties – Make Property Readonly for Outside Class Calls

cocoaobjective-c

Would you know a way to make a property readonly for outside calls and readwrite for inside calls ?

I've read times ago somthing that seemed like

In the .h

@property(nonatomic, readonly) NSDate* theDate;

In the .m

@interface TheClassName()
@property(nonatomic, retain) NSDate* theDate;
@end

but this raises a warning when compiling the .m "Property theDate attribute in TheClassName class continuation does not match class TheClassName property".

Anyway, it seems to work (can read but not set from outside the class, can do both from inside) but I should have missed somehting to avoid the warning.
Or if you know a better way to do this…

Best Answer

In your .h:

@property(nonatomic, retain, readonly) NSDate* theDate;

In your .m:

@interface TheClassName()
@property(nonatomic, retain, readwrite) NSDate* theDate;
@end

Related Solutions

Objective-C Properties – How to Make a Private Property

You want to use a "class extension" rather than a category:

@interface MyClass ()
@property (nonatomic, retain) NSMutableArray *stuff;
@end

@implementation MyClass
@synthesize stuff; // ok

Class extensions were created in Objective-C 2.0 in part specifically for this purpose. The advantage of class extensions is that the compiler treats them as part of the original class definition and can thus warn about incomplete implementations.

Besides purely private properties, you can also create read-only public properties that are read-write internally. A property may be re-declared in a class extensions solely to change the access (readonly vs. readwrite) but must be identical in declaration otherwise. Thus you can do:

//MyClass.h
@interface MyClass : NSObject
{ }
@property (nonatomic,retain,redonly) NSArray *myProperty;
@end

//MyClass.m
@interface MyClass ()
@property (nonatomic, retain, readwrite) NSArray *myProperty;
@end

@implementation MyClass
@synthesize myProperty;
//...
@end

Objective-C – Create Property with Public Readonly and Private Setter

I think what you're looking for are called class extensions. You would declare the property read-only in the header:

@interface MyClass : NSObject {
}

@property (readonly, assign) NSInteger myInteger;

@end

Then redeclare in your class extension in the implementation file:

@interface MyClass ()

@property (readwrite, assign) NSInteger myInteger;

@end


@implementation MyClass

@end

For more check out Apple's documentation

Best Answer

Related Solutions

Objective-C Properties – How to Make a Private Property

Objective-C – Create Property with Public Readonly and Private Setter

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