iOS无法识别的选择器发送到实例 - 将NSDictionary添加到NSMutableArray

Question

为大量代码道歉,但人们最终总是要求批量.

尝试将NSDictionary添加到NSMutableArray时,我收到以下错误

2011-09-22 18:52:54.153 NPT[4788:1603] -[__NSArrayI addObject:]: unrecognized selector sent to instance 0x72f1280
2011-09-22 18:52:54.154 NPT[4788:1603] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayI addObject:]: unrecognized selector sent to instance 0x72f1280'
Call stack at first throw:
(
0   CoreFoundation                      0x028e5919 __exceptionPreprocess + 185
1   libobjc.A.dylib                     0x02a335de objc_exception_throw + 47
2   CoreFoundation                      0x028e742b -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
3   CoreFoundation                      0x02857116 ___forwarding___ + 966
4   CoreFoundation                      0x02856cd2 _CF_forwarding_prep_0 + 50
5   NPT                                 0x00007197 -[Search addPlateToFinals:withSubCount:] + 791
6   NPT                                 0x0000626f -[Search makeNumberedPlatesForPass:] + 1132
7   NPT                                 0x0000401f __-[FirstViewController improveSearch]_block_invoke_1 + 173
8   libSystem.B.dylib                   0x96f02a24 _dispatch_call_block_and_release + 16
9   libSystem.B.dylib                   0x96ef4cf2 _dispatch_worker_thread2 + 228
10  libSystem.B.dylib                   0x96ef4781 _pthread_wqthread + 390
11  libSystem.B.dylib                   0x96ef45c6 start_wqthread + 30
)
terminate called after throwing an instance of 'NSException'

这是抛出错误的代码,据我所知,从堆栈跟踪和使用换行符:

NSDictionary *dPlateToAdd = [NSDictionary dictionaryWithObjects:objects forKeys:keys];       
[self.aFinals addObject:dPlateToAdd];

self.aFinals在接口中被decalared,然后作为属性,然后合成然后初始化如下:

Search.h

@interface Search : NSObject {
...
NSMutableArray *aFinals;
...

}
...
@property (nonatomic, retain) NSMutableArray *aFinals;
...
@end

Search.m

...
@synthesize aFinals;
...

-(id)initWithTerm:(NSString *)thisTerm andPrevResults:(NSMutableArray *)aPrevResults {

    ...
    self.aFinals = [aPrevResults copy];
    ...
}

传入的aPrevResults是先前已发布的搜索对象的属性,但已被复制到视图控制器的属性,并被发送回新的搜索对象,以添加更多结果.

抛出错误的行在第一次传递时工作正常,但是当我重用现在是aPrevResults的数组时,这只会在第二次运行时引起问题.

我做错了什么？这有什么意义呢？

Answer 1

-copy返回不可变对象,即使您在可变数组上调用它也是如此.要获得可变副本,您必须调用mutableCopy方法:

-(id)initWithTerm:(NSString *)thisTerm andPrevResults:(NSMutableArray *)aPrevResults {

    ...
    self.aFinals = [aPrevResults mutableCopy];
    ...
}

此外,由于您正在使用保留属性,因此您需要补偿额外的增量以保留副本上发生的计数:

 self.aFinals = [[aPrevResults mutableCopy] autorelease];

或者,可能是使用便捷类方法的最佳和最干净的解决方案:

 self.aFinals = [NSMutableArray arrayWithArray:aPrevResults];