声明没有实例变量的属性

Question

由于Xcode现在自动添加@synthesis，如何在没有相应的ivar的情况下声明属性？

Answer 1

您需要实现getter和setter，然后它将不会自动合成并自动创建ivar。

Answer 2

@interface Obj : NSObject
@property NSString* str;
@end

@implementation

-(NSString*) str {
    //TODO:
    return @"sdfsdf";
}

-(void) setStr:(NSString*) st {
//TODO:
}

@end

Naming convention is simple:

getter has the same name as the property (in example it is str), setter must have set prefix, ie setPropertyName (first letter of property name is uppercase: setStr:)

You can also add attributes like atomic, retain, strong etc. but they will have no effect in case you're implementing properties yourself, but it's a good hint for the users of your class.