Question

This works fine if the textField is containing any text. But if the textField is empty, no objects are added.

How to tell this piece of code that if the textField is empty, all objects should be added to resultObjectsArray?

resultObjectsArray = [NSMutableArray array];
for(NSDictionary *object in allObjectsArray)
{

    NSString *nameString = [NSString stringWithFormat:@"%@", [textField text]];
    NSString *wineName = [wine objectForKey:@"Name"];
    NSRange range = [wineName rangeOfString:nameString options:NSCaseInsensitiveSearch];

    if ((range.location != NSNotFound))
        [resultObjectsArray addObject:object];
}

Answer 1

resultObjectsArray = [NSMutableArray array];
NSString *nameString = [textField text];
for(NSDictionary *object in allObjectsArray)
{
    if ([nameString length] > 0)
    {
        NSString *wineName = [wine objectForKey:@"Name"];
        NSRange range = [wineName rangeOfString:nameString options:NSCaseInsensitiveSearch];
        if ((range.location != NSNotFound))
            [resultObjectsArray addObject:object];
    }
    else
    {
        [resultObjectsArray addObject:object];
    }
}

Note that you don’t need:

NSString *nameString = [NSString stringWithFormat:@"%@", [textField text]];

as

NSString *nameString = [textField text];

is sufficient. Also it won’t change inside the for loop so can be initialised outside of it.