当我从 History Core Data 对象记录/请求值时,以下代码返回以下错误:
-[CFNumber release]: message sent to deallocated instance 0x17ea2a90
我最初认为其他地方存在问题,并且花了无数个小时试图调试它,但没有成功。经过进一步测试,我已经确定崩溃是从 History Core Data 对象请求某些值。任何人都可以看到为什么对象值被释放的任何问题吗?
[[DocumentHandler sharedDocumentHandler] performWithDocument:^(UIManagedDocument *document) {
if(!self.document) {
self.document = document;
}
__block NSString *identifier = [[NSUserDefaults standardUserDefaults] objectForKey:kUserDefaultsUserIdentifier];
[self.document.managedObjectContext performBlock:^{
// Create history object
History *history = [NSEntityDescription insertNewObjectForEntityForName:@"History"
inManagedObjectContext:self.document.managedObjectContext];
history.identifier = identifier;
history.followers = [NSNumber numberWithInteger:53];
history.following = [NSNumber numberWithInteger:53];
history.newFollowers = [NSNumber numberWithInteger:53];
history.unfollowers = [NSNumber numberWithInteger:53];
history.fans = [NSNumber numberWithInteger:53];
history.mutualFriends = [NSNumber numberWithInteger:53];
history.nonFollowers = [NSNumber numberWithInteger:53];
[self.document saveToURL:self.document.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:^(BOOL success) {
// Fetch previous records
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"History"];
request.predicate
= [NSPredicate predicateWithFormat:@"identifier == %@", identifier];
NSError *error = nil;
NSArray *records = [self.document.managedObjectContext executeFetchRequest:request error:&error];
[records enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSLog(@"%@", [(History *)obj newFollowers]); // Crash takes place here
}];
}];
}];
}];
启用了异常断点的更多日志:
(lldb) bt
* thread #1: tid = 0x28b70, 0x3b5787fa libobjc.A.dylib`objc_release + 10, queue = 'com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=1, address=0x10)
frame #0: 0x3b5787fa libobjc.A.dylib`objc_release + 10
frame #1: 0x3b578022 libobjc.A.dylib`(anonymous namespace)::AutoreleasePoolPage::pop(void*) + 358
frame #2: 0x311b4298 CoreFoundation`_CFAutoreleasePoolPop + 16
frame #3: 0x3127533e CoreFoundation`__NSArrayEnumerate + 614
frame #4: 0x31216012 CoreFoundation`-[NSArray enumerateObjectsWithOptions:usingBlock:] + 62
frame #5: 0x000eae26 Twitter Followers`__71-[MainViewController updateCurrentRecordAndTableHeaderForUpdateAction:]_block_invoke_2(.block_descriptor=0x15e58080, success='\x01') + 678 at MainViewController.m:671
frame #6: 0x3ba65bea libdispatch.dylib`_dispatch_barrier_sync_f_slow_invoke + 66
frame #7: 0x3ba600ee libdispatch.dylib`_dispatch_client_callout + 22
frame #8: 0x3ba629a8 libdispatch.dylib`_dispatch_main_queue_callback_4CF + 268
frame #9: 0x3124b5b8 CoreFoundation`__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
frame #10: 0x31249e84 CoreFoundation`__CFRunLoopRun + 1308
frame #11: 0x311b4540 CoreFoundation`CFRunLoopRunSpecific + 524
frame #12: 0x311b4322 CoreFoundation`CFRunLoopRunInMode + 106
frame #13: 0x35eeb2ea GraphicsServices`GSEventRunModal + 138
frame #14: 0x33a6b1e4 UIKit`UIApplicationMain + 1136