我刚开始在sql-lite中使用核心数据,所以我有点新。我基于各种教程在线创建了一个xcode核心数据应用程序供参考。对于它的价值,我将它整合到现有的cocos2d应用程序中。核心数据只能节省大约50%的时间
一切都还好,直到我注意到储蓄并不总是工作。尽管上下文保存总是返回true,但有时我在取回旧数据时会返回该数据。不会产生错误。我已经调试过,以确保我传递了正确的数据来保存,但我不知道我做错了什么。
这是我的“SaveDataManager”的一部分,它处理保存和检索数据。它是我的应用程序委托的实例对象。
保存功能。
- (bool) saveSongOptionData
{
NSManagedObjectContext *context = ((AppDelegate*)[[UIApplication sharedApplication] delegate]).managedObjectContext;
NSManagedObject *newData = [NSEntityDescription insertNewObjectForEntityForName:@"SongOptions" inManagedObjectContext:context];
NSEntityDescription *entityDesc = [NSEntityDescription entityForName:@"SongOptions" inManagedObjectContext:context];
//First check if row exists, if not create it. If so, update that row with our new high score information.
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDesc];
//Only should be 1 record, grab it
[request setFetchLimit:1];
NSManagedObject *matches = nil;
NSError *error;
NSArray *objects = [context executeFetchRequest:request error:&error];
if ([objects count] == 0) //None!! Lets create one
{
[newData setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].background] forKey:@"background"];
[newData setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].random] forKey:@"random"];
[newData setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].vibrate] forKey:@"vibrate"];
}
else
{
matches = [objects objectAtIndex:0];
[matches setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].background] forKey:@"background"];
[matches setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].random] forKey:@"random"];
[matches setValue:[NSNumber numberWithBool:[GlobalVariables sharedInstance].vibrate] forKey:@"vibrate"];
}
[request release];
bool success = [context save:&error];
if (!success)
NSLog(@"%@", error.localizedDescription);
return success;
}
在我的AppDelegate我创造了我的 “SaveDataManager” 实例,并将它的背景下,像这样的方法的applicationDidFinishLaunching:
self.dataManager = [[SavedDataManager alloc] init];
self.dataManager.managedObjectContext = self.managedObjectContext;
以及用于获取上下文等
#pragma mark - Core Data stack
- (NSManagedObjectContext *)managedObjectContext
{
if (_managedObjectContext != nil)
return _managedObjectContext;
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
_managedObjectContext = [[NSManagedObjectContext alloc] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return _managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel
{
if (_managedObjectModel != nil)
return _managedObjectModel;
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"TestGame" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (_persistentStoreCoordinator != nil)
return _persistentStoreCoordinator;
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TestGame.sqlite"];
NSError *error = nil;
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
{
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return _persistentStoreCoordinator;
}
我不确定这是否有足够的信息,但如果有人能指导我为什么会出现这种情况,我会非常感激。
你是否从主线程保存? – user170317
好问题,基本上我这样称呼保存功能: AppDelegate * d =(AppDelegate *)[[UIApplication sharedApplication] delegate]; [d.dataManager saveSongOptionData]; 您认为这可能是一个问题吗? – Arbel