Objective C - NSDictionary giving error for CTParagraphStyleRef?

CTParagraphStyleRef paraStyle = CTParagraphStyleCreate(alignSettings, 1);
NSDictionary *dictionary = [NSDictionary dictionaryWithObject:paraStyle forKey:kCTParagraphStyleAttributeName];开发者_开发百科

I get a warning on the second line of code "Passing argument 2 from incompatible pointer type " How can I get rid of this warning?

paraStyle is no object, so you cant store it as one. try setValue:forKey: on a NSMuteableDictionary and valueForKey: to retrieve it.

Or wrap your value in a NSValue object.

You are getting the warning because kCTParagraphStyleAttributeName is not an object and can't be used as a key in an NSMutableDictionary. Keys in an NSMutableDictionary must be Objective-C objects that conform to the NSCopying protocol. The CTParagraphStyleRef can't be stored in the dictionary either, because it is likewise not an Obj-C object.

You may want to try using a CFMutableDictionary, whose keys and values can be any C type.