init CBCentralManager: Type of expression is ambiguous without more context












2















Trying to initialize a CBCentralManager in a Swift 4.2 project.
Get the error shown in comment:



import CoreBluetooth

class SomeClass: NSObject, CBCentralManagerDelegate {

// Type of expression is ambiguous without more context
let manager: CBCentralManager = CBCentralManager(delegate: self, queue: nil)

// MARK: - Functions: CBCentralManagerDelegate

func centralManagerDidUpdateState(_ central: CBCentralManager) { }
}


If I switch self out for nil the error goes away, so I think I'm missing something important from my conformance to CBCentralManagerDelegate...



Can I use the manager without a delegate; and if not, what do I need to do to resolve the error?










share|improve this question



























    2















    Trying to initialize a CBCentralManager in a Swift 4.2 project.
    Get the error shown in comment:



    import CoreBluetooth

    class SomeClass: NSObject, CBCentralManagerDelegate {

    // Type of expression is ambiguous without more context
    let manager: CBCentralManager = CBCentralManager(delegate: self, queue: nil)

    // MARK: - Functions: CBCentralManagerDelegate

    func centralManagerDidUpdateState(_ central: CBCentralManager) { }
    }


    If I switch self out for nil the error goes away, so I think I'm missing something important from my conformance to CBCentralManagerDelegate...



    Can I use the manager without a delegate; and if not, what do I need to do to resolve the error?










    share|improve this question

























      2












      2








      2








      Trying to initialize a CBCentralManager in a Swift 4.2 project.
      Get the error shown in comment:



      import CoreBluetooth

      class SomeClass: NSObject, CBCentralManagerDelegate {

      // Type of expression is ambiguous without more context
      let manager: CBCentralManager = CBCentralManager(delegate: self, queue: nil)

      // MARK: - Functions: CBCentralManagerDelegate

      func centralManagerDidUpdateState(_ central: CBCentralManager) { }
      }


      If I switch self out for nil the error goes away, so I think I'm missing something important from my conformance to CBCentralManagerDelegate...



      Can I use the manager without a delegate; and if not, what do I need to do to resolve the error?










      share|improve this question














      Trying to initialize a CBCentralManager in a Swift 4.2 project.
      Get the error shown in comment:



      import CoreBluetooth

      class SomeClass: NSObject, CBCentralManagerDelegate {

      // Type of expression is ambiguous without more context
      let manager: CBCentralManager = CBCentralManager(delegate: self, queue: nil)

      // MARK: - Functions: CBCentralManagerDelegate

      func centralManagerDidUpdateState(_ central: CBCentralManager) { }
      }


      If I switch self out for nil the error goes away, so I think I'm missing something important from my conformance to CBCentralManagerDelegate...



      Can I use the manager without a delegate; and if not, what do I need to do to resolve the error?







      ios swift core-bluetooth cbcentralmanager






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 19 '18 at 22:21









      MercutioMercutio

      390525




      390525
























          1 Answer
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          2














          The diagnostic here is misleading. The problem is you can't refer to self in the place you are (self there would be the class, not the instance).



          There are a few ways to solve this, but a common way is a lazy property:



          lazy var manager: CBCentralManager = {
          return CBCentralManager(delegate: self, queue: nil)
          }()


          The other approach is a ! variable:



          var manager: CBCentralManager!

          override init() {
          super.init()
          manager = CBCentralManager(delegate: self, queue: nil)
          }


          Both are somewhat ugly, but they're about the best we can do in Swift currently.



          Remember that the lazy approach won't create the CBCentralManager at all until the first time it's referenced, so it's a bit more common to use the ! version for this particular case.






          share|improve this answer























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            1 Answer
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            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            The diagnostic here is misleading. The problem is you can't refer to self in the place you are (self there would be the class, not the instance).



            There are a few ways to solve this, but a common way is a lazy property:



            lazy var manager: CBCentralManager = {
            return CBCentralManager(delegate: self, queue: nil)
            }()


            The other approach is a ! variable:



            var manager: CBCentralManager!

            override init() {
            super.init()
            manager = CBCentralManager(delegate: self, queue: nil)
            }


            Both are somewhat ugly, but they're about the best we can do in Swift currently.



            Remember that the lazy approach won't create the CBCentralManager at all until the first time it's referenced, so it's a bit more common to use the ! version for this particular case.






            share|improve this answer




























              2














              The diagnostic here is misleading. The problem is you can't refer to self in the place you are (self there would be the class, not the instance).



              There are a few ways to solve this, but a common way is a lazy property:



              lazy var manager: CBCentralManager = {
              return CBCentralManager(delegate: self, queue: nil)
              }()


              The other approach is a ! variable:



              var manager: CBCentralManager!

              override init() {
              super.init()
              manager = CBCentralManager(delegate: self, queue: nil)
              }


              Both are somewhat ugly, but they're about the best we can do in Swift currently.



              Remember that the lazy approach won't create the CBCentralManager at all until the first time it's referenced, so it's a bit more common to use the ! version for this particular case.






              share|improve this answer


























                2












                2








                2







                The diagnostic here is misleading. The problem is you can't refer to self in the place you are (self there would be the class, not the instance).



                There are a few ways to solve this, but a common way is a lazy property:



                lazy var manager: CBCentralManager = {
                return CBCentralManager(delegate: self, queue: nil)
                }()


                The other approach is a ! variable:



                var manager: CBCentralManager!

                override init() {
                super.init()
                manager = CBCentralManager(delegate: self, queue: nil)
                }


                Both are somewhat ugly, but they're about the best we can do in Swift currently.



                Remember that the lazy approach won't create the CBCentralManager at all until the first time it's referenced, so it's a bit more common to use the ! version for this particular case.






                share|improve this answer













                The diagnostic here is misleading. The problem is you can't refer to self in the place you are (self there would be the class, not the instance).



                There are a few ways to solve this, but a common way is a lazy property:



                lazy var manager: CBCentralManager = {
                return CBCentralManager(delegate: self, queue: nil)
                }()


                The other approach is a ! variable:



                var manager: CBCentralManager!

                override init() {
                super.init()
                manager = CBCentralManager(delegate: self, queue: nil)
                }


                Both are somewhat ugly, but they're about the best we can do in Swift currently.



                Remember that the lazy approach won't create the CBCentralManager at all until the first time it's referenced, so it's a bit more common to use the ! version for this particular case.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 19 '18 at 22:32









                Rob NapierRob Napier

                201k28297423




                201k28297423






























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