Bool Property Cannot be marked dynamic in swift

问题

I'm trying to observe Bool value in swift using KVO and add dynamic modifier like this :

dynamic var isRestricted:Bool?

and the compiler say

Property cannot be marked dynamic because its type canot be represented in Objective-C

then what should I do? should I change to NSNumber for this? and What is the best practice for observing value then?

im using xcode 7 beta 2

回答1:

The actual problem is that optional booleans cannot be represented in Objective-C (and therefore not marked dynamic). Using a non-optional

dynamic var isRestricted : Bool = false

should solve the problem.

Generally, the concept of "optionals" does not exist in Objective-C, but optional references to instances of NSObject subclasses are bridged to nullable object pointers in Objective-C, so

dynamic var foo: Foo?

is allowed if (and only) if Foo is a subclass of NSObject.

来源：https://stackoverflow.com/questions/31131149/bool-property-cannot-be-marked-dynamic-in-swift