NSPredicate - filtering values based on a BOOLEAN stored value

user_394540 0
Viewed 39071

I have a core data model object called Entry. In this I have an attribute IsFavorite.

I would like to use an NSPredicate to filter the results of my NSFetchedResultsController.

Currently I am getting EXC_BAD_ACCESS when the fetch executes.

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate. 

NSEntityDescription *thisEntry = [NSEntityDescription entityForName:@"Entry" inManagedObjectContext:managedObjectContext_];
[fetchRequest setEntity:thisEntry];

NSPredicate *fetchPredicate = [NSPredicate predicateWithFormat:@"Entry.isFavorite == %@", [NSNumber numberWithBool: YES]];

[fetchRequest setPredicate:predicate];


NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"];
aFetchedResultsController.delegate = self;


NSError *error = nil;
if (![aFetchedResultsController performFetch:&error]) {
    NSlog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

IF I remove the line that sets the predicate on the fetchRequest, my code executes perfectly.

I am clearly n00bin out on the predicate but have had much trouble trying to find out how to perform operations on a BOOLEAN value from a core data model object. It is noted that there are answers on how to do this with a string or int value but I can't find a BOOLEAN example.

Many thanks !

nspredicate xcode boolean iphone
9 Answers

If you know you're looking for a YES (and therefore don't need to switch between YES or NO in different situations), this worked for me:

[NSPredicate predicateWithFormat:@"isFavorite == 1"]
user_12579170

Interestingly if you "know" which one you want, you can just have:

let p = NSPredicate(format: "showMe == true")

example,

let r = NSFetchRequest<NSFetchRequestResult>(entityName: "CDThing")
let p = NSPredicate(format: "showMe == true")
r.predicate = p

You would do this for things like "subscribed", "new" etc.

user_2948840

on iOS 10, xcode 9.0, looking for a core data managedObject with Boolean NO attribute:

[NSPredicate predicateWithFormat:@"attributeName == nil"]
user_29467820

Check nil OR false

If you didn't set value before , it may come into nil category even if Bool data type

 let predicate = NSPredicate(format: "isDeviceLine == nil OR isDeviceLine == %@", NSNumber(value: false))
user_17402500
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