ManagedObjectContext

先在該view controller定義一個
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext; 


在<ClassName>AppDelegate.m 中的 - (BOOL)application:didFinishLaunchingWithOptions: 把managedObjectContext帶給viewController的managedObjectContext。如此一來在可以view controller就可以用了。

    rootViewController.managedObjectContext = context;

找出是哪一個Context

    Cost *costEvnet = (Cost *)[NSEntityDescription insertNewObjectForEntityForName:@"Cost" inManagedObjectContext:self.managedObjectContext];

    

設定內容

    [costEvnet setType:@"Food"];

    [costEvnet setMoney:[NSNumber numberWithInt:200]];

    [costEvnet setCostDate:[NSDate date]];

    

存檔

    NSError *error = nil;

    if (![self.managedObjectContext save:&error]) {

        NSLog(@"RootViewController save Failed.");

    }

建立要求

    NSFetchRequest *request = [[NSFetchRequest alloc] init];

    [request setEntity:entityDescription];

執行要求並回傳到Array中

    NSError *error = nil;

    NSMutableArray *objects = [[self.managedObjectContext executeFetchRequest:request error:&error] mutableCopy];

刪除記錄

        NSManagedObject *eventToDelete = [ self.contextMutableArray objectAtIndex:indexPath.row];

        [self.managedObjectContext deleteObject:eventToDelete];