Converting NSEnum from Userinfo in NSNotification fails in Objective c - c++

Question

I want to convert userInfo data from a NSNotification to an enum to use in a switch statement. The notification is coming from a pre-compiled c++ framework with some headerfiles defining te enum.
-(void)updateOTAStatus:(NSNotification *)notification {
NSDictionary *userInfo = notification.userInfo;
otaUpgradeStatus status = (otaUpgradeStatus)userInfo[#"status"];
//...
}
Enum definition:
typedef NS_ENUM(NSUInteger, otaUpgradeStatus) {
none = 0,
started = 1,
inProgress = 2,
completed = 3,
failed = 4,
failedLowBattery = 5,
cancelled = 6,
timedout = 7,
forced = 8
};
When debugging I get
Printing description of status:
(otaUpgradeStatus) status = 6178538944
And switch statement fails, when I do the same in Swift:
let status = notification.userInfo?["status"] as? otaUpgradeStatus
I get the right status back, and switch statement works as expected.
What goes wrong here?

Answer 1

An NSDictionary can only hold objects, i.e. instances of (a subclass of) NSObject. Swift has a mechanism to wrap/unwrap values in an
opaque _SwiftValue instance transparently.
But for interoperability with Objective-C you have to put the number
as NSNumber instances into the user info dictionary on the Swift side, e.g.
let notification = Notification(name: ..., object: ...,
userInfo: ["status": NSNumber(value: otaUpgradeStatus.failed.rawValue)])
and extract the integer value on the Objective-C side, e.g.
NSDictionary *userInfo = notification.userInfo;
NSNumber *num = userInfo[#"status"];
otaUpgradeStatus status = num.unsignedIntegerValue;