覆盖具有弧和动态属性的setter [英] Overriding setters with arc and dynamic properties

问题描述

我需要在setter方法中做一些额外的事情。但是这样做会得到一个无限循环：

I need to do some additional stuff in a setter method. But I get an infinite loop when doing so:

我有一个核心数据对象

@interface Transaction : NSManagedObject 
@property (nonatomic, retain) NSDate * date;
@end

@implementation Transaction
@dynamic date;

-(void)setDate:(NSDate *)date
{
    self.date = date;
    //additional stuff omitted
}

所以，在这种情况下，我得到无限循环。好吧所以我在网上搜索并按以下方式修改我的代码，每个版本我都会遇到编译错误

So, in that case I get an infinite loop. Okay so I searched on the net and modified my code in the following way and for every version I get compiler errors

版本1：

@interface Transaction : NSManagedObject 
@property (nonatomic, retain) NSDate * date;
@end

@implementation Transaction
@dynamic date;

-(void)setDate:(NSDate *)date
{
    self->date = date; //Error: Property 'date' found on object 'Transaction *'; did you mean to access it with the "." operator?
    //additional stuff omitted
}

版本2：

@interface Transaction : NSManagedObject 
@property (nonatomic, retain) NSDate * date;
@end

@implementation Transaction
@dynamic date = _date; //Error: Expected ';' after @dynamic

-(void)setDate:(NSDate *)date
{
    _date = date; 
    //additional stuff omitted
}

现在，我问自己这个怎么做？

Now, I'm asking myself how to do this?

推荐答案

我的问题的解决方案：

@interface Transaction : NSManagedObject 
@property (nonatomic, retain) NSDate * date;
@end

@implementation Transaction
@dynamic date;

-(void)setDate:(NSDate *)date
{
    [self setPrimitiveValue:date forKey:@"date"];
    //additional stuff omitted
}

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