Question

I’m trying to grope my way through Obj-C to build an iPhone game.

I’d like to build an array of objects for later use. Here’s what I tried:

NSMutableArray      *positionIcons;
[positionIcons insertObject:annotation atIndex:0];
positionIcons = [NSArray arrayWithObjects:annotation, nil];

The insertObject line leaves the count at 0. However, the next line correctly inserts the object (and count moves to 1). What gives?

Answer 1

You need to initialize positionIcons, change the code to:

NSMutableArray *positionIcons = [[NSMutableArray alloc] init];
[positionIcons insertObject:annotation atIndex:0];
positionIcons = [NSArray arrayWithObjects:annotation, nil];