CODEWITHSUNDEEP
ioscore-data
mvasco
mvasco

Reputation: 5101

Warning at method definition

Following method is showing me a warning, but the app is executing as expected. Please could you check the code and tell me what is wrong there? Only if this important to the app, if the warning is not dangering the app, then tell me if I could let this as it is...thank you

The warning is : Incompatible pointer types assigning to 'NSMutableArray *' from 'NSArray *' at the method definition.

-(void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope {
    self.searchResults = [[self.fetchedResultsController fetchedObjects] filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) 
    {
    ToDoItem * item = evaluatedObject;
    NSString* name = item.todoName;

    //searchText having length < 3 should not be considered
    if (!!searchText && [searchText length] < 3) {
        return YES;
    }

    if ([scope isEqualToString:@"All"] || [name isEqualToString:scope])  {
        return ([name rangeOfString:searchText].location != NSNotFound);
    }
    return NO; //if nothing matches
}]];
}

Upvotes: 0

Views: 62

Answers (2)

nhgrif
nhgrif

Reputation: 62062

self.searchResults = [[[self.fetchedResultsController fetchedObjects] 
    filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:
    ^BOOL(id evaluatedObject, NSDictionary *bindings) mutableCopy];

mutableCopy is a method on many objects for which a mutable and immutable version exists. In the case of things like NSArray, NSString, NSData, etc, calling mutableCopy on one of these instances will return a mutable version containing the same contents as the original object you called the method on.

For example, 

NSArray *immutableArray = [NSArray arrayWithObjects:@"foo",@"bar"];
NSMutableArray *mutableArray = [immutableArray mutableCopy];

However, if you don't intend for searchResults to be an NSMutableArray, you should change it's declaration:

@property (nonatomic,strong) NSArray *searchResults

If you don't intend it to be mutable, it should be declared as immutable.

Given your claim that the warning is not effecting the performance of your app, my best guess is that the proper solution would be changing searchResults from NSMutableArray to NSArray.

Upvotes: 1

Martin R
Martin R

Reputation: 539975

filteredArrayUsingPredicate returns an immutable NSArray, and you seem to have declared searchResults as NSMutableArray.

So either

  • change the declaration of searchResults to NSArray, or
  • make a mutableCopy before assigning it.

The proper solution depends on whether you need to modify the searchResults later or not.

Upvotes: 1

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