核心數據在iOS 4.3中不起作用

Question

我的核心數據有問題。 它在iOS 5.0和更高版本上運行，但是當我在iOS 4.3中運行時，它崩潰了，它在__managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];行上崩潰__managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType]; 有人可以幫我嗎？

2012-05-08 17:01:21.617 [7489:10e03] -[NSManagedObjectContext initWithConcurrencyType:]: unrecognized selector sent to instance 0x4ddc6c0
2012-05-08 17:01:21.650 [7489:10e03] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSManagedObjectContext initWithConcurrencyType:]: unrecognized selector sent to instance 0x4ddc6c0'
*** Call stack at first throw:
(
    0   CoreFoundation                      0x0111e5a9 __exceptionPreprocess + 185
    1   libobjc.A.dylib                     0x0153c313 objc_exception_throw + 44
    2   CoreFoundation                      0x011200bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
    3   CoreFoundation                      0x0108f966 ___forwarding___ + 966
    4   CoreFoundation                      0x0108f522 _CF_forwarding_prep_0 + 50
    5   0x00002a42 -[AppDelegate managedObjectContext] + 194
    6   0x00003736 -[HomeViewController fetchFeedDataIntoDocument] + 134
    7   Amsterdam                   0x0000417d -[HomeViewController refresh] + 45
    8   Amsterdam                   0x0000803f -[MBProgressHUD launchExecution] + 143
    9   Foundation                          0x00ae2cf4 -[NSThread main] + 81
    10  Foundation                          0x00ae2c80 __NSThread__main__ + 1387
    11  libsystem_c.dylib                   0x93393ed9 _pthread_start + 335
    12  libsystem_c.dylib                   0x933976de thread_start + 34
)
terminate called throwing an exception(lldb) 

Answer 1

initWithConcurrencyType：NSMainQueueConcurrencyType是新的，是5.0

http://developer.apple.com/library/ios/#releasenotes/General/iOS50APIDiff/index.html

您需要在使用前檢查版本。

您將需要檢查版本，並使用init替代早期版本。