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IPhone: warning pops up when reverse NSMutablearray

I need a reverse (sorting descending) NSMutablearray. I tried the following code and it works but got a warning. How can I remove the warning?

NSMutablearray *resStatusArray;

[resStatusArray sortUsingSelector:@selector(compare:)];

    resStatusArray=[[resStatusArray reverseObjectEnumerator] allObjects];

      

        
        
        
      

    
Warning:Incompitable pointer types assigning to 'NSMutablearray*_strong' from ' NSarray *'
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4 answers


user1118321 is correct in the explanation. To fix this, you must create a new mutable array. I suspect it is safer than casting.



resStatusArray = [NSMutableArray arrayWithArray:[[resStatusArray reverseObjectEnumerator] allObjects]];
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The method allObjects

returns NSArray*

, not NSMutableArray*

, which is why the compiler tells you your variable assignment is NSMutableArray*

wrong.



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If you are sure of what you are doing, you can use a cast:

resStatusArray=(NSMutableArray*_strong)[[resStatusArray reverseObjectEnumerator] allObjects];

However, I doubt this is semantically correct.

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Set it equal:

[NSMutableArray arrayWithArray:[[arrayNameToReverse reverseObjectEnumerator] allObjects]];

This essentially creates a new array from the old modified array, but vice versa. The reason it works is because NSMutableArray is a subclass of NSArray. So your code to modify your array will look like this:

resStatusArray = [NSMutableArray arrayWithArray:[[resStatusArray reverseObjectEnumerator] allObjects]];
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