index 0 beyond bounds for empty array error

Question

I don\'t understand on how to debug this error message:

2011-02-01 20:45:56.151 NeMe[3206:207] *** Terminating app due to uncaught exception \'NSRangeExcepti         


        

Answer 1

It means that early in [NeighborMapViewController regionFromLocations] you are attempting to index an NSMutableArray object. That array has zero elements in it -- it's empty. But you're apparently trying to access index 0, which would be the first element. Since there is no first element, you get an exception.

Probably the code that you expect to have executed to add items to the array has not yet executed, or you simply need to check the length of the array prior to trying to access the element at index 0. It's hard to say without knowing more about what you're doing.

gdb reports the offset as 65 bytes in to the function, so it's likely in one of the first few lines. You could probably manually inspect the code of the function to see, or set a breakpoint on the first line of the function and step through it.