IOS / Objective-C：从JSON获取数字

Question

I have a JSON dictionary that contains what I will call an integer (in mathematics) ie 1.

I would like to save this number to a core data attribute that is an NSInteger . The following code is issuing warning:

Incompatible Pointer to Integer Conversion initializing NSInteger with an expression of type 'id'

 NSInteger insertID = jsonResults[@"insert_id"];

I have tried various combinations of int , NSNumber , etc. to no avail. Can anyone suggest right way to do this?

Answer 1

NSDictionary can't store NSInteger . It is storing NSNumber . So you need to unwrap the NSNumber :

NSInteger insertID = [jsonResults[@"insert_id"] integerValue];

Answer 2

in core data you should save numeric value as Number Type. For eaxample,

To save:

insert_id = @(100)//say 100 is your insert_id value

To read:

NSInteger insertID = [jsonResults[@"insert_id"] intValue];