键入'className -> () -> className!‘不符合协议

Question

我在和斯威夫特胡闹。我有一个协议被定义为

protocol timerProtocol {
    func timerFired()
}

持有对委托的引用的类

class Stopwatch: NSObject {
    var delegate: protocol <timerProtocol>

    init(delegate: protocol <timerProtocol> ) {
        self.delegate = delegate
    }

...
}

和一个实现该协议的类

class StopwatchesTableViewController: UITableViewController, timerProtocol {

    func timerFired() {
        println("timer");
    }

    let stopwatch = Stopwatch(delegate: self) // Error here

...
}

声明秒表时出现错误--“类型'StopwatchesTableViewController -> () -> StopwatchesTableViewController!‘不符合协议'timerProtocol'”

如何解决此问题？

Answer 1

更改var delegate: protocol <timerProtocol>

转到var delegate: timerProtocol?

Answer 2

从语法和逻辑上讲，这对我来说就像一个护身符：

protocol TimerProtocol {
    func timerFired()
}

class Stopwatch {
    var delegate: protocol <TimerProtocol>? = nil
    
    init() { }
    
    convenience init(delegate: protocol <TimerProtocol> ) {
        self.init()
        self.delegate = delegate
    }

}

class StopwatchesTableViewController: UITableViewController, TimerProtocol {
    
    @lazy var stopwatch: Stopwatch = Stopwatch()
    
    init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        stopwatch.delegate = self
    }
    
    func timerFired() {
        println("timer");
    }

}

注意:协议的名称应以大写字母开头。

或

StopwatchesTableViewController类将如下所示：

class StopwatchesTableViewController: UITableViewController, TimerProtocol {
    
    var stopwatch: Stopwatch? = nil
    
    init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        stopwatch = Stopwatch(delegate: self)
    }
    
    func timerFired() {
        println("timer");
    }

}

Answer 3

试着改变，

let stopwatch = Stopwatch(delegate: self) // Error here

至

@lazy var stopwatch: Stopwatch = Stopwatch(delegate: self)