如何在Swift中初始化对象期间将self传递给初始化程序？

Question

我有以下代码:

import CoreBluetooth

class BrowserSample: NSObject, CBCentralManagerDelegate {
    let central : CBCentralManager

    init() {
        central = CBCentralManager(delegate: self, queue: nil, options: nil)
        super.init()
    }

    func centralManagerDidUpdateState(central: CBCentralManager!)  { }
}

如果我central =之前把线放super.init(),那我得到错误:

self used before super.init() call

如果我把它放在后面,我得到错误:

Property self.central not initialized at super.init call

所以,我很困惑.我该怎么做呢？

Answer 1

一种解决方法是使用ImplicitlyUnwrappedOptional这样central与初始化nil第一

class BrowserSample: NSObject, CBCentralManagerDelegate {
    var central : CBCentralManager!

    init() {
        super.init()
        central = CBCentralManager(delegate: self, queue: nil, options: nil)
    }

    func centralManagerDidUpdateState(central: CBCentralManager!)  { }
}

或者你可以试试 @lazy

class BrowserSample: NSObject, CBCentralManagerDelegate {
    @lazy var central : CBCentralManager = CBCentralManager(delegate: self, queue: nil, options: nil)

    init() {
        super.init()
    }

    func centralManagerDidUpdateState(central: CBCentralManager!)  { }
}