Ios 托管对象上下文未合并来自后台上下文的更改
我有一个双重管理对象上下文设置,其中我有一个父/子MOC关系。父线程负责直接写入私有队列上的数据库(NSPrivateQueueConcurrencyType),然后我有一个子上下文,负责为主线程(NSMainQueueConcurrencyType)提取和保存数据 当我对主队列上下文进行更改并保存它时,上下文的工作方式应该是这样的,然后这些更改被合并到后台队列上下文中,并在后台线程上写入数据库 我遇到的问题是,我将数据直接写入后台队列上下文,然后尝试将其合并到主队列上下文。对象正确地存储在存储区中,当我合并更改时,它似乎可以工作。但是,如果在将数据保存到存储区后直接尝试对主队列上下文发出NSFetchRequest,则数据已过时,不是正确的更新数据 下面是代码摘录,可以帮助大家了解我在做什么。需要注意的是,从JSON返回NSManagedObject的逻辑工作正常。此外,我已经测试了mergeChangesFromContextDidSaveNotification,并在UI尝试对主队列MOC发出任何获取请求之前运行。你们都知道发生了什么事吗Ios 托管对象上下文未合并来自后台上下文的更改,ios,core-data,Ios,Core Data,我有一个双重管理对象上下文设置,其中我有一个父/子MOC关系。父线程负责直接写入私有队列上的数据库(NSPrivateQueueConcurrencyType),然后我有一个子上下文,负责为主线程(NSMainQueueConcurrencyType)提取和保存数据 当我对主队列上下文进行更改并保存它时,上下文的工作方式应该是这样的,然后这些更改被合并到后台队列上下文中,并在后台线程上写入数据库 我遇到的问题是,我将数据直接写入后台队列上下文,然后尝试将其合并到主队列上下文。对象正确地存储在存储
// Context Setup
- (NSManagedObjectContext *)backgroundWriterManagedObjectContext
{
if (_backgroundWriterManagedObjectContext != nil)
return _backgroundWriterManagedObjectContext;
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
_backgroundWriterManagedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
_backgroundWriterManagedObjectContext.persistentStoreCoordinator = coordinator;
_backgroundWriterManagedObjectContext.mergePolicy = NSMergeByPropertyStoreTrumpMergePolicy;
_backgroundWriterManagedObjectContext.undoManager = nil;
}
return _backgroundWriterManagedObjectContext;
}
- (NSManagedObjectContext *)managedObjectContext
{
if (_managedObjectContext != nil)
return _managedObjectContext;
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
_managedObjectContext.parentContext = _backgroundWriterManagedObjectContext;
_managedObjectContext.mergePolicy = NSMergeByPropertyStoreTrumpMergePolicy;
_managedObjectContext.stalenessInterval = 0.0;
}
return _managedObjectContext;
}
// save MOC
- (void)saveManagedObjectContext
{
@try
{
// perform synchronous process to save to the main MOC
[_managedObjectContext performBlockAndWait:^(void)
{
__block NSError *error = nil;
// push any changes in the main context to the background writer context
if (![_managedObjectContext tryLock])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Unable To Lock Managed Object Context: %@", error.localizedDescription]];
if (![_managedObjectContext save:&error])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Error Saving Managed Object Context: %@", error.localizedDescription]];
[_managedObjectContext unlock];
// save the background writer context
[_backgroundWriterManagedObjectContext performBlock:^(void)
{
error = nil;
if (![_backgroundWriterManagedObjectContext tryLock])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Unable To Lock Background Writer Managed Object Context: %@", error.localizedDescription]];
if (![_backgroundWriterManagedObjectContext save:&error])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Error Saving Background Writer Managed Object Context: %@", error.localizedDescription]];
[_backgroundWriterManagedObjectContext unlock];
}];
}];
}
@catch (NSException *exception)
{
[VS_Log VS_LogException:exception];
}
}
// This code runs when attempting to save objects from a web service call
[_backgroundWriterManagedObjectContext performBlock:^(void)
{
// create a new process object and add it to the dictionary
__block VS_CoreDataRequest *request = [[VS_CoreDataRequest alloc] init];
// .. LOGIC HERE DESERIALIZES THE JSON AND RETURNS AN ARRAY OF NSMANAGEDOBJECTS
// perform synchronous process to save to the main MOC
@try
{
NSError *error = nil;
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeChangesFromContextDidSaveNotification:) name:NSManagedObjectContextDidSaveNotification object:_backgroundWriterManagedObjectContext];
if (![_backgroundWriterManagedObjectContext tryLock])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Unable To Lock Background Writer Managed Object Context: %@", error.localizedDescription]];
if (![_backgroundWriterManagedObjectContext save:&error])
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManger - Error Saving Background Writer Managed Object Context: %@", error.localizedDescription]];
[_backgroundWriterManagedObjectContext unlock];
// submit changes back to the forground context
[_managedObjectContext performBlock:^(void)
{
NSMutableArray *objects = [[NSMutableArray alloc] init];
// iterate through the updated objects and find them in the main thread MOC
for (VS_BaseManagedObject *object in request.objects)
{
// get the object from the main managed object context
NSError *error;
NSManagedObject *obj = [_managedObjectContext existingObjectWithID:object.objectID error:&error];
if (error)
[VS_Log VS_LogError:[NSString stringWithFormat:@"VS_CoreDataManager - Error: %@", error.localizedDescription]];
if (obj)
{
[_managedObjectContext refreshObject:obj mergeChanges:YES];
[objects addObject:obj];
}
}
// RETURN FROM METHOD SO UI CAN REGAIN CONTROL
}];
}
@catch (NSException *exception)
{
[VS_Log VS_LogException:exception];
return;
}
}];
// Merges changes from parent to child context
- (void)mergeChangesFromContextDidSaveNotification:(NSNotification *)notification
{
// remove observer
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSManagedObjectContextDidSaveNotification object:_backgroundWriterManagedObjectContext];
// merge the changes
[_managedObjectContext mergeChangesFromContextDidSaveNotification:notification];
}
您没有调用进程挂起的更改 由于您的代码和概念看起来还不错,所以您提供的信息中有些地方没有意义。您是否使用FRC向视图提供数据?如果是这样的话,我怀疑这与你的财务报告准则有关。我不确定独立获取是否会按照您的要求更新MOC。我会调查的。