CoreDataDemoSnippet

CoreDataDemoSnippet.mm

#pragma mark - CoreDataAbout

- (void)saveContext
{
    NSError* error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            NSLog(@"Unresolved error :%@, %@", error, [error userInfo]);
            abort();
        }else{
            NSLog(@"save success!");
        }
    }
}

- (NSURL*)applicationDocDir
{
    NSURL* url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask]lastObject];
    NSLog(@"%@", [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]);
    
    return url;
}

// 后缀为.xcdatamodeld的包，里面是.xcdatamodel文件，用数据模型编辑器编辑
// 编译后为.momd或.mom文件
- (NSManagedObjectModel*)managedObjectModel
{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    
    NSURL* modelURL = [[NSBundle mainBundle] URLForResource:@"Journal" withExtension:@"momd"];
    NSLog(@"model url: %@", [modelURL path]);
    self.managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    
    return self.managedObjectModel;
}

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

- (NSPersistentStoreCoordinator*)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }
    
    NSURL* storeUrl = [[self applicationDocDir] URLByAppendingPathComponent:@"Journal.sqlite"];
    
    NSError* error = nil;
    self.persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    
    if (![self.persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&error]) {
        NSLog(@"Error: %@, %@", error, [error userInfo]);
    }
    
    return self.persistentStoreCoordinator;
}