Unable to assign object retrieved from NSMutableArray

Question

For some reason I am unable to assign an object which I retrieve from a mutable array

UPDATE: Note that I'm using ARC

Here is the code:

id<Control> control = [formControlUtils getControlWithId:@"123"];
// Here control.controlValue is "Old value"
control.controlValue = @"New value";
// Even after assigning a new value to the property the value is still "Old value"

- (id<Control>)getControlWithId:(NSString *)controlId {
id<Control> control = nil;

for (NSArray *array in [FormRenderManager sharedInstance].formControls)
{
    //[FormRenderManager sharedInstance].formControls is a mutable array, so is the nested arrays
    control = [[array filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"controlId = %@", controlId]] lastObject];

    if (control)
        break;
}

return control;
}

As you can see in my code comments above, whenever a assign a new value to control.controlValue the old value still persists.

Why is that? Do I perhaps miss something fundamental here or is it due to the fact that I work against a protocol <id>Control control ?

Does [FormRenderManager sharedInstance].formControls always return the same array, or a new autoreleased instance for each call? — user529758
– user529758, Commented Nov 1, 2012 at 9:11
I've updated my question to point out that I'm using ARC. [FormRenderManager sharedInstance].formControls will always return the same array. — RynoB
– RynoB, Commented Nov 1, 2012 at 9:14
thanks! Very strange in this case... I'll think about it more. — user529758
– user529758, Commented Nov 1, 2012 at 9:19

Mundi · Accepted Answer · 2012-11-01 09:59:20Z

1

filteredArrayUsingPredicate returns an immutable array. You will have to do this:

[NSMutableArray arrayWithArray:[array filtered...]];

answered Nov 1, 2012 at 9:59

Mundi

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