I've got the following swift autogen model, that i can't change
#objcMembers public class Device: NSObject, Codable {
public enum Auth: String, Codable {
case enabled = "ENABLED"
case supported = "SUPPORTED"
case notSupported = "NOT_SUPPORTED"
case bypassed = "BYPASSED"
}
public var auth: Auth
public var brand: String
}
I'm trying to access the enum property in my Objective-C class like this
self.isAuthEnabled = ([Device.auth.rawValue isEqualToString:#"ENABLED"]);
but I keep getting this error, Property 'auth' not found on object of type 'Device' even though I have access to the brand property, I can't access the enum
Related
I have generated classes for two core data entities. The first is called Address and is an abstract entity. The second is called Person, and it inherits from Address. I've added a few example managed attributes for the purpose of this test. And i've added a non-managed String property to the Person class. Accessing the string property of the Person class will crash. Why does this crash?
The Address and Person classes are automatically generated by Xcode, with the exception of the extra parameter: let foo = "Foo"
If i modify the code to make Person inherit from NSManagedObject directly instead of Address, then the code works and doesn't crash.
Automatically generated Address class:
#objc(Address)
public class Address: NSManagedObject {
}
extension Address {
#nonobjc public class func fetchRequest() -> NSFetchRequest<Address> {
return NSFetchRequest<Address>(entityName: "Address")
}
#NSManaged public var street: String?
#NSManaged public var city: String?
}
Automatically generated person class with the exception of the "foo" parameter:
#objc(Person)
public class Person: Address {
public let foo = "Foo" //added this parameter
}
extension Person {
#nonobjc public class func fetchRequest() -> NSFetchRequest<Person> {
return NSFetchRequest<Person>(entityName: "Person")
}
#NSManaged public var name: String?
}
problem code
let person = Person(context: context)
print(person.foo) //doesn't crash, but prints empty line instead of value
print("VALUE:\(person.foo):") //crashes with Thread 1: EXC_BAD_ACCESS (code=1, address=0x18)
UPDATE:
if foo is defined as
public let foo: String? = "Foo"
then the print statements don't crash, instead they interpret the value as 'nil' and print that.
So my question becomes: Why is this value which is assigned as a constant being reset to nil under the covers?
I have two hand-waving explanations why you are getting nil:
Managed objects don't function very well until they are inserted.
Your foo is a what I would call a constant stored property. I made up the name because, red flag, I cannot find any examples of it in the Swift book chapter on Properties
Put these two together and you get an edge case that doesn't work.
That being said, I'm kind of surprised that your foo setting does not work, because foo is not a managed property (that is, it is not in the data model). If I make such a constant stored property in a regular, non-managed object…
public class Animal {
public let foo: String! = "Foo"
}
it reads back later as expected.
So, if you can accept that this edge case just doesn't work in Core Data, you can move on to several more normal ways that do work.
One way is to declare foo as a var and assign a value to in awakeFromInsert() which is, as I alluded to earlier, after insertion. In Core Data, awakeFromInsert() is one of your friends…
#objc(Person)
public class Person: Address {
public var foo: String!
override public func awakeFromInsert() {
foo = "Foo"
}
}
Another way that works is as a computed property…
#objc(Person)
public class Person: Address {
public var foo : String { return "Foo" }
}
And, finally, the most logical way, since foo is constant for all instances, is to make it a type property…
#objc(Person)
public class Person: Address {
static var foo: String = "Foo"
}
but of course if you do this you must reference it as Person.foo instead of person.foo.
So I´m trying to build a framework with a function like this
public func logScreen(screen: SomeEnum){
print(screen.rawValue)
}
and i want to pass as parameter a case of a string enum that is defined in the project that will make use of this framework
I don't think you can do this directly. But using swift protocol, you can achieve your goal I believe. You may review my idea.
First, you need to define a protocol in your framework. Say in you Framework class.
public protocol SomeEnum {
var rawValue: String { get }
}
Inside your framework class, you define your code:
public func logScreen(screen: SomeEnum){
print(screen.rawValue)
}
Now in your project, you can declare the enum and inherite the framework
protocol. Say for example in your project:
public enum MyEnum: SomeEnum {
case test
case debug
public var rawValue: String {
switch self {
case .test:
return "test"
case .debug:
return "Debug"
}
}
}
Now use the method from your project like below:
yourframeworkclass.logScreen(screen: MyEnum.test)
Not able to figure why my class does not conform to Codable
Please not that in my case I do not need to implement the methods encode and decode.
public class LCLAdvantagePlusJackpotCache: Codable {
public let token: String
public let amount: NSNumber
public let member: Bool
public init(token: String, amount: NSNumber, member: Bool) {
self.token = token
self.amount = amount
self.member = member
}
enum CodingKeys: String, CodingKey {
case token, amount, member
}
}
It's because NSNumber is not Codable. Do not use Objective-C types; use Swift types. (That's a general rule; it isn't confined to the Codable situation. But this is a good example of why the rule is a good one!)
Change NSNumber to Int or Double (in both places where it occurs in your code) and all will be well.
I'm trying to get a simple NSManagedObject class to conform to Encodable so that I can easily encode it to JSON.
I have an entity named TestObject that has a one to many relationship with an entity named Device.
Everything works fine until I try to encode an NSSet (to many relationship).
import UIKit
import CoreData
import Foundation
#objc(TestObject)
public class TestObject:NSManagedObject,Encodable
{
#nonobjc public class func fetchRequest() -> NSFetchRequest<TestObject> {
return NSFetchRequest<TestObject>(entityName: "TestObject")
}
#NSManaged public var testName: String?
#NSManaged public var devices: NSSet? // of entity type "Device"
enum CodingKeys: String, CodingKey {
case testName
case devices
}
public func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy:CodingKeys.self)
try container.encode(testName,forKey:.testName)
try container.encode(devices,forKey:.devices)
}
}
The error I receive from the compiler is
reference to member 'devices' cannot be resolved without a contextual type
try container.encode(devices,forKey:.devices)
What is this compiler telling me and how can I encode my objects along with its relationships?
How to confirm to protocols that declares properties of other protocols in Swift?
There is a protocol GKGameModel in which its implementers need to have a properties conforming to a protocol
public protocol GKGameModel {
// ...
public var players: [GKGameModelPlayer]? { get }
public var activePlayer: GKGameModelPlayer? { get }
// ...
}
public protocol GKGameModelPlayer {
// ...
}
Now, suppose I have a class Player and GameModel that conforms to the above protocols
class Player : NSObject, GKGameModelPlayer {
//...
}
class GameModel : NSObject, GKGameModel {
//...
public var players: [Player]?
public var activePlayer: Player?
}
Now the above code doesn't compile and the error messages (among others) were:
protocol requires property 'activePlayer' with type 'GKGameModelPlayer?'; do you want to add a stub?
candidate has non-matching type 'Player?'
However the Player class conforms to protocol GKGameModelPlayer, hence it should confirm just fine. How can I get this to compile?
Strangely Objective-C deals with this just fine – take a look at the FourInARow example code which does something like this.
The protocol requires that the properties be typed exactly as shown. In other words, an array of GKGameModelPlayers and a single optional GKGameModelPlayer?. If your Player type conforms to the protocol, then an array of Players can be passed to the protocol property if casted / typed as [GKGameModelPlayer].
But the requirement here is not, for example, an activePlayer property that has a type that conforms to GKGameModelPlayer, but rather an activePlayer property that references an instance that it typed as / cast as a GKGameModelPlayer.
I.e. this would fix the error:
class GameModel : NSObject, GKGameModel {
//...
public var players: [GKGameModelPlayer]?
public var activePlayer: GKGameModelPlayer?
}
players and activePlayer property has a type that conforms to GKGameModelPlayer. So just change it to GKGameModelPlayer type instead of Player
class GameModel : NSObject, GKGameModel {
//...
public var players: [GKGameModelPlayer]?
public var activePlayer: GKGameModelPlayer?
}