ios - 两天后核心数据消失

Question

我正在使用核心数据来保存我的数据。对于前两天，它存储数据就很好。但是，两天后数据丢失。我已经多次测试了此结果，结果相同。我想念什么吗？有人有什么建议吗？下面是我的CoreDataStack类。非常感谢!

#import <Foundation/Foundation.h>

@interface CoreDataStack : NSObject

+(instancetype)defaultStack;

@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;

- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
@end

和实现文件

#import "CoreDataStack.h"

@implementation CoreDataStack


@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

+(instancetype)defaultStack{
    static CoreDataStack  *defaultStack;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        defaultStack = [[self alloc]init];
    });

    return defaultStack;
}

- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }
}

#pragma mark - Core Data stack

// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return _managedObjectContext;
}

// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"Wen" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return _managedObjectModel;
}

// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"Wen.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;
}

#pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
    NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
   NSLog(@"%@", url.absoluteString);
    return url;
}

@end

插入条目功能...忽略它说乳房:)它是一个婴儿记录应用程序

(void)insertLogEntry {
CoreDataStack *coreDataStack = [CoreDataStack defaultStack];
BreastEntry *entry = [NSEntityDescription insertNewObjectForEntityForName:@"BreastEntry" inManagedObjectContext:coreDataStack.managedObjectContext];

/* Information i left out that is being stored */

[coreDataStack saveContext];

}

Answer 1

我认为应用程序一直都在打开吗？您是否尝试过使用saveToPersistentStore:而不是save:？如果您终止该应用程序并重新启动该应用程序，是否可以维护您的数据？

编辑:除非您使用RestKit，否则忽略saveToPersistentStore:注释。