Question

I am getting below error that causing crash.

Terminating app due to uncaught exception NSGenericException reason Collection CALayerArray was mutated while being enumerated.
Any help would be highly appreciated.

Answer 1

“mutated while being enumerated” – this happens when, for instance, you enumerate through the contents of an array, and then inside the enumeration loop, you remove or add an object to the array.

 for ( NSObject *obj in myMutableArray ) {
      if ( <some_condition_is_true> ) {
          [myMutableArray removeObject: obj];   // CRASH!!
      }
 }

Usually, if you want to modify an array, but you need to find which member to modify, you’d either make a copy of the array and enumerate that, and then do your mod,

or

make a reference to the object you want to delete, and do the delete outside of the loop. Like so:

 NSObject *toast=nil;
 for ( NSObject *obj in myMutableArray ) {
     if ( this_is_the_one_to_delete ) {
         toast = obj;
         break;
     }
 }
 if ( toast ) {
     [myMutableArray removeObject:toast];
 }