NSFetchedResultsController删除所有

Question

AcaniChat，像原生iPhone消息应用程序中，必须清除所有消息的方法：

for (Message *message in [fetchedResultsController_ fetchedObjects]) { 
    [managedObjectContext_ deleteObject:message]; 
} 
if (![managedObjectContext_ save:&error]) { 
    // TODO: Handle the error appropriately. 
    NSLog(@"Delete message error %@, %@", error, [error userInfo]); 
} 

但是，只有当有很多信息被删除（不够，有些是关屏）与错误AcaniChat崩溃：

2011-04-10 01:06:17.629 AcaniChat[11129:207] Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. CoreData could not fulfill a fault for '0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42>' with userInfo { 
    NSAffectedObjectsErrorKey =  (
     "<Message: 0x4d665b0> (entity: Message; id: 0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42> ; data: <fault>)" 
    ); 
} 
2011-04-10 01:06:17.721 AcaniChat[11129:207] Delete message error Error Domain=NSCocoaErrorDomain Code=133000 "The operation couldn’t be completed. (Cocoa error 133000.)" UserInfo=0x4d9cf70 {NSAffectedObjectsErrorKey=(
    "<Message: 0x4d665b0> (entity: Message; id: 0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42> ; data: <fault>)" 
), NSUnderlyingException=CoreData could not fulfill a fault for '0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42>'}, { 
    NSAffectedObjectsErrorKey =  (
     "<Message: 0x4d665b0> (entity: Message; id: 0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42> ; data: <fault>)" 
    ); 
    NSUnderlyingException = "CoreData could not fulfill a fault for '0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42>'"; 
} 
2011-04-10 01:06:18.036 AcaniChat[11129:207] CoreAnimation: ignoring exception: CoreData could not fulfill a fault for '0x4d7d050 <x-coredata://F07CAEF9-5F38-4A1F-BA17-52A3E2E56978/Message/p42>' 

我该如何解决这个问题？

Answer 1

我通过设置fetchedResultsController_.delegate = nil，删除在cellMap所有对象（实际上是对于UITableView *chatContent数据源，因为我添加NSDate对象cellMap用于时间戳的细胞），然后，设置fetchedResultsController_.delegate = self以及执行固定该取指令再次请求。

NSError *error; 
fetchedResultsController.delegate = nil;    // turn off delegate callbacks 
for (Message *message in [fetchedResultsController fetchedObjects]) { 
    [managedObjectContext deleteObject:message]; 
} 
if (![managedObjectContext save:&error]) { 
    // TODO: Handle the error appropriately. 
    NSLog(@"Delete message error %@, %@", error, [error userInfo]); 
} 
fetchedResultsController.delegate = self;    // reconnect after mass delete 
if (![fetchedResultsController performFetch:&error]) { // resync controller 
    // TODO: Handle the error appropriately. 
    NSLog(@"fetchMessages error %@, %@", error, [error userInfo]); 
} 
[cellMap removeAllObjects]; 
[chatContent reloadData]; 

Answer 2

此外，检查出MagicalRecord。它有一个+truncateAll方法。