無法識別的選擇發送到定製類

下面的實例類的頭：無法識別的選擇發送到定製類

@interface ChallengeItem : NSObject 
....... 
- (NSString *) getAlertIntervalInString; 
- (void) createReminder; 

@end 

some implementation in .m file: 

- (NSString *) getAlertIntervalInString { 
... do something 
} 

- (void)createReminder { 
... do something 
}

我打電話

for (int i = 0; i < [self count]; i++) { 
    ChallengeItem *currentItem = [self getChallengeAtIndex:i]; 
    if (currentItem.isStarted) { 
     [currentItem createReminder]; 
    } 
}

，並收到一個無法識別的選擇錯誤，但是當我改變

[currentItem createReminder];

到

[currentItem getAlertIntervalInString];

錯誤未出現。問題是什麼？

這裏是控制檯日誌

當前語言：汽車;當前objective-c 2011-11-23 00：56：40.056 30天挑戰[379：12b03] - [ChallengeItem createReminder]：
無法識別的選擇器發送到實例0x6079900 2011-11-23 00：56：40.147 30天挑戰[379：12b03] *終止應用程序由於未捕獲的異常 'NSInvalidArgumentException'，原因是： ' - [ChallengeItem createReminder]：無法識別的選擇發送到實例0x6079900' *調用堆棧在第一擲：

(
    0 CoreFoundation      0x00fb35a9 __exceptionPreprocess + 185 
    1 libobjc.A.dylib      0x01107313 objc_exception_throw + 44 
    2 CoreFoundation      0x00fb50bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187 
    3 CoreFoundation      0x00f24966 ___forwarding___ + 966 
    4 CoreFoundation      0x00f24522 _CF_forwarding_prep_0 + 50 
    5 30 Day Challenge     0x00006950 -[ChallengeCollection setRemindersForStartedChallenges] + 144 
    6 30 Day Challenge     0x00002f27 -[_0_Day_ChallengeAppDelegate applicationDidEnterBackground:] + 151 
    7 UIKit        0x00209a40 -[UIApplication _handleApplicationSuspend:eventInfo:] + 607 
    8 UIKit        0x00213039 -[UIApplication handleEvent:withNewEvent:] + 4127 
    9 UIKit        0x0020aabf -[UIApplication sendEvent:] + 71 
    10 UIKit        0x0020ff2e _UIApplicationHandleEvent + 7576 
    11 GraphicsServices     0x01712992 PurpleEventCallback + 1550 
    12 CoreFoundation      0x00f94944 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52 
    13 CoreFoundation      0x00ef4cf7 __CFRunLoopDoSource1 + 215 
    14 CoreFoundation      0x00ef1f83 __CFRunLoopRun + 979 
    15 CoreFoundation      0x00ef1840 CFRunLoopRunSpecific + 208 
    16 CoreFoundation      0x00ef1761 CFRunLoopRunInMode + 97 
    17 GraphicsServices     0x017111c4 GSEventRunModal + 217 
    18 GraphicsServices     0x01711289 GSEventRun + 115 
    19 UIKit        0x00213c93 UIApplicationMain + 1160 
    20 30 Day Challenge     0x00002059 main + 121 
    21 30 Day Challenge     0x00001fd5 start + 53 
    22 ???         0x00000001 0x0 + 1 
) 
terminate called throwing an exception(gdb)

來源

2011-11-22 Vitaliy Gozhenko

我們可以從控制檯看到實際的崩潰日誌嗎？ –

顯示代碼getChallengeAtIndex – tiltem

- （ChallengeItem *）getChallengeAtIndex：（NSInteger）index { \t return [self.challenges objectAtIndex：index]; } –