NSMutablearray move object from index to index

Question

I have a UItableview with reordable rows and the data is in an NSarray. So how do I move an object in the NSMutablearray when the appropriate tableview delegate is called?

Another way to ask this is how to reorder an NSMutableArray?

Answer 1

id object = [[[self.array objectAtIndex:index] retain] autorelease]; [self.array removeObjectAtIndex:index]; [self.array insertObject:object atIndex:newIndex]; 

That's all. Taking care of the retain count is important, since the array might be the only one referencing the object.

Answer 2

ARC compliant category:

NSMutableArray+Convenience.h

@interface NSMutableArray (Convenience)

- (void)moveObjectAtIndex:(NSUInteger)fromIndex toIndex:(NSUInteger)toIndex;

@end

NSMutableArray+Convenience.m

@implementation NSMutableArray (Convenience)

- (void)moveObjectAtIndex:(NSUInteger)fromIndex toIndex:(NSUInteger)toIndex
{
    // Optional toIndex adjustment if you think toIndex refers to the position in the array before the move (as per Richard's comment)
    if (fromIndex < toIndex) {
        toIndex--; // Optional 
    }

    id object = [self objectAtIndex:fromIndex];
    [self removeObjectAtIndex:fromIndex];
    [self insertObject:object atIndex:toIndex];
}

@end

Usage:

[mutableArray moveObjectAtIndex:2 toIndex:5];