Odtnhj

I'm new to Swift (background in C++) and I'm trying to do a very simple thing: save a Bool. It works perfectly if I convert the bool to a string that is either "A" or "B" and then convert back but if I save the bool directly with encode and aDecoder the Bool comes back nil every time. Can't find anything about it on the internet.

As you can see below I simply substitute a string for a Bool and it works.

func boolwontsave(aBool:Bool) -> String 
 if aBool 
 return "A"
 
 return "B"


func encode(with aCoder: NSCoder) 

 aCoder.encode(name, forKey: PropertyKey.name)
 aCoder.encode(number, forKey: PropertyKey.number)
 aCoder.encode(boolwontsave(aBool: ispresent), forKey: PropertyKey.present)



required convenience init?(coder aDecoder: NSCoder) 

 // The name is required. If we cannot decode a name string, the initializer should fail.
 guard let name = aDecoder.decodeObject(forKey: PropertyKey.name) as? String else 
 os_log("Unable to decode the name for a player object.", log: OSLog.default, type: .debug)
 return nil
 

 let number = aDecoder.decodeObject(forKey: PropertyKey.number) as? String

 guard let localpresent = aDecoder.decodeObject(forKey: PropertyKey.present) as? String else 
 print("got the nil")
 os_log("Unable to decode the ispresent for a player object.", log: OSLog.default, type: .debug)
 return nil
 


 // Must call designated initializer.
 self.init(name:name, number:number, present: localpresent == "A")

Aren't Bools supposed to save? This seems inelegant.

It's very easy to save a Bool if you are using the proper API.

In terms of NSCoding a Bool is not an object, there is a decodeBool(forKey method.

required convenience init?(coder aDecoder: NSCoder) 

 // The name is required. If we cannot decode a name string, the initializer should fail.
 guard let name = aDecoder.decodeObject(forKey: PropertyKey.name) as? String else 
 os_log("Unable to decode the name for a player object.", log: OSLog.default, type: .debug)
 return nil
 

 let number = aDecoder.decodeObject(forKey: PropertyKey.number) as? String
 let localpresent = aDecoder.decodeBool(forKey: PropertyKey.present)

 // Must call designated initializer.
 self.init(name:name, number:number, present: localpresent)



func encode(with aCoder: NSCoder) 
 aCoder.encode(name, forKey: PropertyKey.name)
 aCoder.encode(number, forKey: PropertyKey.number)
 aCoder.encode(ispresent, forKey: PropertyKey.present)

In Swift 4+ I'd prefer the native Codable protocol over constrained NSCoding.

• 
  NSCoding requires an class inherited from NSObject.


• 
  Codable can be used for any struct, class and enum which conforms to the protocol.

Use decodeBool(forKey key: String) instead of decodeObject(forKey: String)

DecodeBool decodes and returns a boolean value that was previously encoded with encode(_:forKey:) and associated with the string key.

aCoder.encode(true, forKey: PropertyKey.present)
aCoder.decodeBool(forKey: PropertyKey.present)