当我尝试调用 self.init 时，我的便捷初始化器出了什么问题？

Question

我写了下面的代码。当我尝试调用 self.init 时，我得到的错误是在我的便利初始化程序结束时。我的逻辑或语法有什么问题？或者我将如何调试它？ Xcode 给出的错误是 "cannot invoke with an argument list of type".

感谢您对此的任何帮助

import Foundation
import UIKit

class Item: NSObject {

    var name: String
    var valueInDollars: Int
    var serialNumber: String?
    let dateCreated: NSDate
    var stolen: Bool?

    init(name: String, valueInDollars: Int, serialNumber: String?, dateCreated: NSDate, stolen: Bool?) {
        self.name = name
        self.valueInDollars = valueInDollars
        self.serialNumber = serialNumber
        self.dateCreated = NSDate()
        self.stolen = stolen

        //below why did I have to call super.init for this custom class that inherits from NSObject? Doesn't it automatically get called anyway once the custom object is initialized since it inherits from NSObject?  It just seems like more work on my behalf which isn't fair.  it should do it automatically.  Why wouldn't it do it automatically if it inherits from NSObject?
        super.init()
    }

    convenience init(random: Bool = false) {
        if random {
            let adjectives = ["Fluffy", "Rusty", "Shiny"]
            let nouns = ["MacBook Pro", "Red Tribe Bike", "Vegan Pizzas"]
            //take a variable that's random; the highest value for this random number will be the number of ojbects in the adjectives array
            var idx = arc4random_uniform(UInt32(adjectives.count))
            //now use this random variable and let it be the index of the adjectives array...so basically it'll be a random object from the adjectives array
            let randomAdjective = adjectives[Int(idx)]

            //AWESOME!! Now that the random adjective is stored in the randomAdjective constant, let's re-use the idx variable...Ayyyyeeeee re-use!

            //we'll re-use it by doing the same process or close to the same process for nouns
            idx = arc4random_uniform(UInt32(nouns.count))
            let randomNoun = nouns[Int(idx)]

            //now let's concatenate these two clever words, shall we!!
            let randomName = "\(randomAdjective) \(randomNoun)"

            //yayyy we're programmmminnngg!

            //now let's ....whad de fuk....
            let randomValue = Int(arc4random_uniform(100))
            let randomSerialNumber = NSUUID().uuidString.components(separatedBy: "-").first!

            let betterNotBeStolen: Bool = false

            self.init(name: randomName, valueInDollars: randomValue, serialNumber: randomSerialNumber, stolen: betterNotBeStolen)


        }
    }
}

Answer 1

你遇到了错误

"Cannot invoke 'Item.init' with an argument list of type '(name: String, valueInDollars: Int, serialNumber: String, stolen: Bool)'"

因为您错过了 self.init(params...) 中的 dateCreated 参数。

所以你需要替换这一行

self.init(name: randomName, valueInDollars: randomValue, serialNumber: randomSerialNumber, stolen: betterNotBeStolen)

有了这个

self.init(name: randomName, valueInDollars: randomValue, serialNumber: randomSerialNumber,dateCreated: NSDate(), stolen: betterNotBeStolen)

您将看到的下一个错误是

Self.init isn't called on all paths before returning from initializer

因此您需要添加 else 语句，因为当随机参数为 false 时，初始化器不知道要做什么。

convenience init(random: Bool = false) {
        if random {
            let adjectives = ["Fluffy", "Rusty", "Shiny"]
            let nouns = ["MacBook Pro", "Red Tribe Bike", "Vegan Pizzas"]
            //take a variable that's random; the highest value for this random number will be the number of ojbects in the adjectives array
            var idx = arc4random_uniform(UInt32(adjectives.count))
            //now use this random variable and let it be the index of the adjectives array...so basically it'll be a random object from the adjectives array
            let randomAdjective = adjectives[Int(idx)]

            //AWESOME!! Now that the random adjective is stored in the randomAdjective constant, let's re-use the idx variable...Ayyyyeeeee re-use!

            //we'll re-use it by doing the same process or close to the same process for nouns
            idx = arc4random_uniform(UInt32(nouns.count))
            let randomNoun = nouns[Int(idx)]

            //now let's concatenate these two clever words, shall we!!
            let randomName = "\(randomAdjective) \(randomNoun)"

            //yayyy we're programmmminnngg!

            //now let's ....whad de fuk....
            let randomValue = Int(arc4random_uniform(100))
            let randomSerialNumber = NSUUID().uuidString.components(separatedBy: "-").first!

            let betterNotBeStolen: Bool = false

            self.init(name: randomName, valueInDollars: randomValue, serialNumber: randomSerialNumber,dateCreated: NSDate(), stolen: betterNotBeStolen)


        } else {

           self.init(name: "SomeName", valueInDollars: 3, serialNumber: "123", dateCreated: NSDate(), stolen: true)
        }
    }

当我尝试调用 self.init 时，我的便捷初始化器出了什么问题？

Whats wrong with my convenience initializer when I attempt to call self.init?

initialization

convenience-methods

swift