NSCompoundPredicate - objective-c

Question

I'm trying to filter a UITableView's data using a UISearchDisplayController and NSCompoundPredicate. I have a custom cell with 3 UILabels that I want to all be filtered within the search, hence the NSCompoundPredicate.
// Filter the array using NSPredicate(s)
NSPredicate *predicateName = [NSPredicate predicateWithFormat:#"SELF.productName contains[c] %#", searchText];
NSPredicate *predicateManufacturer = [NSPredicate predicateWithFormat:#"SELF.productManufacturer contains[c] %#", searchText];
NSPredicate *predicateNumber = [NSPredicate predicateWithFormat:#"SELF.numberOfDocuments contains[c] %#",searchText];
// Add the predicates to the NSArray
NSArray *subPredicates = [[NSArray alloc] initWithObjects:predicateName, predicateManufacturer, predicateNumber, nil];
NSCompoundPredicate *compoundPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:subPredicates];
However, when I do this, the compiler warns me:
Incompatible pointer types initializing 'NSCompoundPredicate *_strong'
with an expression of type 'NSPredicate *'
Every example I've seen online does this exact same thing, so I'm confused. The NSCompoundPredicate orPredicateWithSubpredicates: method takes an (NSArray *) in the last parameter, so I'm REALLY confused.
What's wrong?

Answer 1

First of all, using "contains" is very slow, consider mayber "beginswith"?
Second, what you want is:
NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:subPredicates];
Three, you could've just done something like:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF.productName beginswith[cd] %# OR SELF.productManufacturer contains[cd] %#", searchText, searchText];

Answer 2

orPredicateWithSubpredicates: is defined to return an NSPredicate*. You should be able to change your last line of code to:
NSPredicate *compoundPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:subPredicates];
... and still have all of the compoundPredicates applied.

Answer 3

Here's an useful method i created based on the answers above (which i thank very much!)
It allows to create an NSPredicate dynamically, by sending an array of filter items and a string which represents the search criteria.
In the original case, the search criteria changes, so it should be an array instead of a string. But it may be helpful anyway
- (NSPredicate *)dynamicPredicate:(NSArray *)array withSearchCriteria:(NSString *)searchCriteria
{
NSArray *subPredicates = [[NSArray alloc] init];
NSMutableArray *subPredicatesAux = [[NSMutableArray alloc] init];
NSPredicate *predicate;
for( int i=0; i<array.count; i++ )
{
predicate = [NSPredicate predicateWithFormat:searchCriteria, array[i]];
[subPredicatesAux addObject:predicate];
}
subPredicates = [subPredicatesAux copy];
return [NSCompoundPredicate orPredicateWithSubpredicates:subPredicates];
}