CODEWITHSUNDEEP
iosuitableviewcore-data
VansFannel
VansFannel

Reputation: 45921

One FetchedResultsController for two UITableViews in one UIViewController

I'm developing an iOS app with latest SDK and XCode 4.5.2 that uses Core Data.

On an UIViewController I will have two UITableView, shopsList and productsList. I want to use Core Data and this is my first time that I use it. So, I've started using Xcode Master Detail template and I have found this code on MasterViewController.m:

- (NSFetchedResultsController *)fetchedResultsController
{
    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    // Set the batch size to a suitable number.
    [fetchRequest setFetchBatchSize:20];

    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
    NSArray *sortDescriptors = @[sortDescriptor];

    [fetchRequest setSortDescriptors:sortDescriptors];

    // Edit the section name key path and cache name if appropriate.
    // nil for section name key path means "no sections".
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Master"];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;

    NSError *error = nil;
    if (![self.fetchedResultsController performFetch:&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();
    }

    return _fetchedResultsController;
}

If I have this UIViewController interface:

@interface FirstViewController : UIViewController<CLLocationManagerDelegate, UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate>
{
    CLLocationManager* locationManager;
    BOOL isMenuHidden;
    BOOL isShopsListOpen;
    BOOL isProductsListOpen;
    long int selectedShopRow;
    long int selectedProductRow;
    NSIndexPath* shopCheckedIndexPath;
    NSIndexPath* productCheckedIndexPath;
}

@property (unsafe_unretained, nonatomic) IBOutlet UITableView *shopsList;
@property (unsafe_unretained, nonatomic) IBOutlet UITableView *productsList;

[ ... ]

If I have a shop and a product NSManagedObject.

How can I could adapt - (NSFetchedResultsController *)fetchedResultsController to work with these two UITableView?

I will probably need to NSFetchedResultsController, isn't it?

Upvotes: 0

Views: 354

Answers (2)

Mundi
Mundi

Reputation: 80265

The solution is to go with two instances of NSFetchedResultsController. I have a similar setup in one of my apps.

I recommend defining the fetched results controllers as @propertys of the view controller.

Important: don't forget check for which controller is called in your FRC delegate callbacks such as controller:didChangeObject:....

Upvotes: 0

stack
stack

Reputation: 126

First assign managedObjectContext of your viewController in app delegate.

@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (strong, nonatomic) NSFetchedResultsController *productsListFetchedResultsController;
@property (strong, nonatomic) NSFetchedResultsController *shopsListFetchedResultsController;

Create 2 entity in your data model, and fill some available data in appdelegate if need.

In viewWillAppear, you fetch 2 entity to 2 NSFetchedResultsController, just drag basic fetchResult block code in the utility Panel and change context to self.manageObjectContext, entity name to associate name

Upvotes: 3

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