Ios xcode-发送到实例的无法识别的选择器

我在另一个类中调用了方法（它们都是单例）

webserviceheloper.h

@interface WebserviceHelper : NSObject {
    int currentType;
    NSString *SERVER_URL;
    WebserviceManager *webService;
}

@property (nonatomic, assign) id delegate;

- (void)retrieveStudentwithCode:(NSString *)code {
    currentType = STUDENT_TYPE;
    NSString *param = [NSString stringWithFormat:@"token=uencom&cid=%@", code];
    NSString *link = [NSString stringWithFormat:@"%@getStudentInfo", SERVER_URL];
    [webService retrieveData:link withParameters:param];
}

调用webservice并获取它缓存在接收数据中的数据后。我检查了一下，一切正常 但是当它交付给

didfishload

时，这里会发生错误

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)receivedData {
    data = [NSMutableData new];
    [data appendData:receivedData];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [self stopPostingToWebservice];
    //it carsh here
    [delegate: data];
}

调用堆栈：

2014-08-20 10:39:05.187 School-Link[1030:60b] -[WebserviceHelper :]: unrecognized selector sent to instance 0xa88a420
2014-08-20 10:39:05.188 School-Link[1030:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[WebserviceHelper :]: unrecognized selector sent to instance 0xa88a420'
*** First throw call stack:
(
    0   CoreFoundation                      0x01bf31e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x018f08e5 objc_exception_throw + 44
    2   CoreFoundation                      0x01c90243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
    3   CoreFoundation                      0x01be350b ___forwarding___ + 1019
    4   CoreFoundation                      0x01be30ee _CF_forwarding_prep_0 + 14
    5   School-Link                         0x00030c82 -[WebserviceManager connectionDidFinishLoading:] + 242
    6   Foundation                          0x016b9e49 ___NSURLConnectionDidFinishLoading_block_invoke + 40
    7   Foundation                          0x016507e1 __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 62
    8   Foundation                          0x014d8f5e -[NSURLConnectionInternalConnection invokeForDelegate:] + 119
    9   Foundation                          0x014d8ec6 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 208
    10  Foundation                          0x014d8dd8 -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 76
    11  Foundation                          0x014d9188 _NSURLConnectionDidFinishLoading + 43
    12  CFNetwork                           0x02a3169f ___ZN27URLConnectionClient_Classic26_delegate_didFinishLoadingEU13block_pointerFvvE_block_invoke + 111
    13  CFNetwork                           0x02a2f3de ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 104
    14  CoreFoundation                      0x01b94c69 CFArrayApplyFunction + 57
    15  CFNetwork                           0x02998441 _ZN19RunloopBlockContext7performEv + 155
    16  CFNetwork                           0x02a7a3f4 _ZThn16_N19RunloopBlockContext24multiplexerClientPerformEv + 20
    17  CFNetwork                           0x02998257 _ZN17MultiplexerSource7performEv + 299
    18  CFNetwork                           0x0299806c _ZN17MultiplexerSource8_performEPv + 76
    19  CoreFoundation                      0x01b7c77f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
    20  CoreFoundation                      0x01b7c1d5 __CFRunLoopDoSources0 + 437
    21  CoreFoundation                      0x01b991ae __CFRunLoopRun + 910
    22  CoreFoundation                      0x01b989d3 CFRunLoopRunSpecific + 467
    23  CoreFoundation                      0x01b987eb CFRunLoopRunInMode + 123
    24  GraphicsServices                    0x0338d5ee GSEventRunModal + 192
    25  GraphicsServices                    0x0338d42b GSEventRun + 104
    26  UIKit                               0x005b0f9b UIApplicationMain + 1225
    27  School-Link                         0x00018f6d main + 141
    28  libdyld.dylib                       0x03026701 start + 1
    29  ???                                 0x00000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

---

您不显示委托的声明，但是以下语句：

[delegate: data];

应该是：

[delegate haveSomeData:data];

---

（或类似内容）

您是否在WebserviceHelper.h文件中创建了如下协议

@protocol WebserviceHelperDelegate <NSObject>

@required
-(void)reciveData:(NSData *)data;//or your method

@end

并从调用webservice类并分配委托的位置实现此方法

-(void)reciveData:(NSData *)data{
}

---

试试这个，在WebserviceHelper.h中有一个协议声明

@protocol studentDataDelegate <NSObject>

    -(void)WebserviceHelper:(WebserviceHelper *)webserviceHelper didStudentDataDownloadCompleteWithData:(NSMutableData *)data;

@end

那么，哪个类确认上述协议应该实现委托方法，比如

@interface RequestingDataClass : UIViewController <studentDataDelegate> 

---

将对象传递给代理的方式是错误的！遵循@trojanfoe语法我对objective c不熟悉，所以我没有这方面的经验。我应该在另一个类中创建新方法来处理来自该类的数据吗one@MohammadShaker如果你想通知代表已经收到数据，我想你会这么做的，你将需要一个类似于我的答案所示的方法。我尝试了这个代码，它让我有很多问题，我在我的朋友代码工作，我不知道他是如何建立它的，但谢谢你的朋友

@protocol studentDataDelegate <NSObject>

    -(void)WebserviceHelper:(WebserviceHelper *)webserviceHelper didStudentDataDownloadCompleteWithData:(NSMutableData *)data;

@end

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [self stopPostingToWebservice];

    [self.delegate WebserviceHelper:self didStudentDataDownloadCompleteWithData:data];
}

@interface RequestingDataClass : UIViewController <studentDataDelegate> 

      -(void)WebserviceHelper:(WebserviceHelper *)webserviceHelper didStudentDataDownloadCompleteWithData:(NSMutableData *)data;
    {
webserviceHelper.delegate=self; 
    // Do something with the `data`
    }