Question

我从服务器获取数据，如

listremainders (
        {
        Remainter = "2014-12-28T19:42:39";
        RemainterDate = "2014-12-04 10:24:57";
        RemainterID = 16;
        RemainterNotes = hjg;
    }

因为我正在检索“剩余价值”。在控制台中它也显示为 dateObj（＆＃34; 2014-12-28T19：42：39＆＃34; ）

我写了这样的代码来从API中检索no.of日期。这是我的代码......

datesArrayOfString = [[NSMutableArray alloc] init];

    for (NSString *dic in (NSMutableArray *)dateObj) {

        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"yyyy-MM-ddTHH:mm:ss"];//date format cin
        NSDate *sDate = [dateFormatter dateFromString:dic];
       // NSDateFormatter *dateFormatterTwo = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"EEEE dd MMM"];
        NSString *dateSTring=[dateFormatter stringFromDate:sDate];
        [datesArrayOfString addObject:dateSTring];
    }

    NSLog(@"array of strings are %@", datesArrayOfString);

当循环发生时，应用程序崩溃。它就像......一样......

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
    0   CoreFoundation                      0x0227bdf6 __exceptionPreprocess + 182
    1   libobjc.A.dylib                     0x01f05a97 objc_exception_throw + 44
    2   CoreFoundation                      0x021331e1 -[__NSArrayM insertObject:atIndex:] + 881
    3   CoreFoundation                      0x02132e41 -[__NSArrayM addObject:] + 65
    4   TimeTableApp                        0x00184416 -[OneToOneViewController CallingListRemaindersServices] + 1926
    5   TimeTableApp                        0x0017da13 -[OneToOneViewController viewDidLoad] + 323
    6   UIKit                               0x00a46d54 -[UIViewController loadViewIfRequired] + 771
    7   UIKit                               0x00a47045 -[UIViewController view] + 35
    8   UIKit                               0x00a5ab09 -[UIViewController _setPresentationController:] + 103
    9   UIKit                               0x00a535c9 -[UIViewController _presentViewController:presentationController:animationController:interactionController:completion:] + 848
    10  UIKit                               0x00a54368 -[UIViewController _presentViewController:withAnimationController:completion:] + 1741
    11  UIKit                               0x00a57032 __62-[UIViewController presentViewController:animated:completion:]_block_invoke + 345
    12  UIKit                               0x00a56e84 -[UIViewController presentViewController:animated:completion:] + 224
    13  UIKit                               0x00fc3011 -[UIPopoverController _presentShimmedPopoverFromRect:inView:permittedArrowDirections:animated:] + 217
    14  UIKit                               0x00fc3211 -[UIPopoverController presentPopoverFromRect:inView:permittedArrowDirections:animated:] + 355
    15  TimeTableApp                        0x001067de -[TimeTableViewController collectionView:didSelectItemAtIndexPath:] + 61534
    16  UIKit                               0x01002dc8 -[UICollectionView _selectItemAtIndexPath:animated:scrollPosition:notifyDelegate:] + 591
    17  UIKit                               0x01020612 -[UICollectionView _userSelectItemAtIndexPath:] + 191
    18  UIKit                               0x01020806 -[UICollectionView touchesEnded:withEvent:] + 492
    19  libobjc.A.dylib                     0x01f1b7cd -[NSObject performSelector:withObject:withObject:] + 84
    20  UIKit                               0x00aa4b44 forwardTouchMethod + 270
    21  UIKit                               0x00aa4bb4 -[UIResponder touchesEnded:withEvent:] + 31
    22  libobjc.A.dylib                     0x01f1b7cd -[NSObject performSelector:withObject:withObject:] + 84
    23  UIKit                               0x00aa4b44 forwardTouchMethod + 270
    24  UIKit                               0x00aa4bb4 -[UIResponder touchesEnded:withEvent:] + 31
    25  libobjc.A.dylib                     0x01f1b7cd -[NSObject performSelector:withObject:withObject:] + 84
    26  UIKit                               0x00aa4b44 forwardTouchMethod + 270
    27  UIKit                               0x00aa4bb4 -[UIResponder touchesEnded:withEvent:] + 31
    28  libobjc.A.dylib                     0x01f1b7cd -[NSObject performSelector:withObject:withObject:] + 84
    29  UIKit                               0x00aa4b44 forwardTouchMethod + 270
    30  UIKit                               0x00aa4bb4 -[UIResponder touchesEnded:withEvent:] + 31
    31  UIKit                               0x00d28257 _UIGestureRecognizerUpdate + 13225
    32  UIKit                               0x0094171b -[UIWindow _sendGesturesForEvent:] + 1356
    33  UIKit                               0x0094257f -[UIWindow sendEvent:] + 769
    34  UIKit                               0x00907aa9 -[UIApplication sendEvent:] + 242
    35  UIKit                               0x009178de _UIApplicationHandleEventFromQueueEvent + 20690
    36  UIKit                               0x008ec079 _UIApplicationHandleEventQueue + 2206
    37  CoreFoundation                      0x0219f7bf __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
    38  CoreFoundation                      0x021952cd __CFRunLoopDoSources0 + 253
    39  CoreFoundation                      0x02194828 __CFRunLoopRun + 952
    40  CoreFoundation                      0x021941ab CFRunLoopRunSpecific + 443
    41  CoreFoundation                      0x02193fdb CFRunLoopRunInMode + 123
    42  GraphicsServices                    0x04c3924f GSEventRunModal + 192
    43  GraphicsServices                    0x04c3908c GSEventRun + 104
    44  UIKit                               0x008efe16 UIApplicationMain + 1526
    45  TimeTableApp                        0x0018f40d main + 141
    46  libdyld.dylib                       0x0314aac9 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

我不知道为什么sDate得到'nil'。但数据是以'dic'形式出现的，但它并没有存储在'sDate'中。

我做错了什么？任何人都可以帮助解决这个问题。我是Objective-c的新手。在此先感谢。

Answer 1

注意-dateFromString方法，注意：

返回值使用。解释的字符串的日期表示接收器的当前设置。如果dateFromString：无法解析 string，返回nil。

Reference Apple Documentation here

如果您无法解析任何条目，则应检查dateFormat属性see this中指示的模式。无论如何，您应该始终检查输入日期格式是否与您的输入字符串匹配，因为如果格式不匹配，您将获得nil。

为避免这种情况，请检查sDate是否为零：

NSDate *sDate = [dateFormatter dateFromString:dic];
if (sDate != nil)
  ...

Answer 2

你的api向你发送带有Dictionary的数组，所以你的循环必须如下所示：

for (NSDictionary *dictionary in NSArray)
{
    for (NSString *key in dictionary) 
    {
       id value = [dictionary objectForKey:key];
       // do stuff
    }
}

when - [__ NSArrayM insertObject：atIndex：]：object不能为nil＆＃39;

2 个答案: