Question

Possible Duplicate:
What is __NSArrayI and __NSArrayM? How to convert to NSArray?

I am getting the error below

2012-06-06 15:53:19.509 NavApp[5462:707] * Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘* -[__NSArrayM insertObject:atIndex:]: object cannot be nil’
*** First throw call stack:
(0x353b788f 0x3775e259 0x3530c1d7 0xba3e5 0xc128b 0x32e2db95 0x32e87d85 0x32e4a251 0x32e49fa1 0x32e49cbb 0x32e49a2f 0x32e00aab 0x32e063d5 0x3220cc2f 0x34246ee7 0x3538a2ad 0x3530d4a5 0x3530d36d 0x36fa9439 0x32e19cd5 0x106a71 0xb8c70)
terminate called throwing an exception(lldb)

I think it’s odd because it says “__NSArrayM”… Any idea what this means?

Answer 1

It seems you are trying to insert a nil object to an NSMutableArray
This will cause an exception, since mutable array cannot contain nil objects

About the __NSArrayM

__NSArrayM is a NSMutableArray
__NSArrayI is a NSArray