What is the best way for defining Property in iPhone

Question

Hi what is the difference between a)

@interface SViewController : UITableViewController{

NSString *_name;

}

@property (nonatomic, retain) NSString *name;


@synthesize name = _name;

---

b)

@interface SViewController : UITableViewController{

NSString *name;

}

@property (nonatomic, retain) NSString *name;

@synthesize name;

Answer 1

Skip the ivar and just have the property declaration. If you need private members and methods, use a class extension.

An example:

@interface MyObject : NSObject {
}

@property (nonatomic,retain) NSString *publicString;

-(void)publicMethod;

@end

and implemention:

#import "MyObject.h"

@interface MyObject ()
@property (nonatomic,retain) NSString *internalString;
-(void)internalMethod;
@end

@implementation MyObject

@synthesize publicString;
@synthesize internalString;

-(void)publicMethod {}
-(void)internalMethod {}

@end

Note: One downside not declaring an ivar and just have the property, is that gdb in Xcode4 (<= 4.0.1) won't show the property when debugging. Very annoying when writing iOS code, as you can't use LLDB for debugging iOS projects yet.

Answer 2

I prefer a) option, as it prevents you from accidentally forgetting to release or over-release resources. You just always access your variable as self.name and assign either nil or autoreleased value (in case it's a retain property as in your example). In this case if you try to assign a value to "name" without "self." you'll get an error.