swift - 快速便捷初始化错误:必须在参数之前

我一直在尝试创建我的第一个方便初始值设定项。我得到这个错误：
我得到错误：参数'valueInDollars'必须在参数'serialNumber'之前
这里是我所有的代码，我的问题是在我的代码的底部，但我认为它是有用的，以显示一切。

import UIKit

class Item: NSObject {

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



init(name: String, valueInDollars: Int, serialNumber: String?) {

self.name = name
    self.valueInDollars = valueInDollars
self.serialNumber = serialNumber
    self.dateCreated = NSDate()

    super.init()

}

//create a random item:

convenience init(random: Bool = false) {

    if random {

    let adjectives = ["Fluffy", "Rusty", "Bluffy"]
        let nouns = ["Boon", "Noon", "Toon",]

    var idx = arc4random_uniform(UInt32(adjectives.count))
    let randomAdjective = adjectives[Int(idx)]

        idx = arc4random_uniform(UInt32(nouns.count))
        let randomNoun = nouns[Int(idx)]


        let randomName = "\(randomAdjective) \(randomNoun)"

        let randomValue = Int(arc4random_uniform(100))

        let randomSerialNumber = NSUUID().UUIDString.componentsSeparatedByString("-").first!


        self.init(name: randomName, serialNumber: randomSerialNumber, valueInDollars: randomValue)
    }
    else {

        self.init(name: "", serialNumber: nil, valueInDollars: 0)



    }
}
}

最佳答案

您应该用定义init本身时使用的参数顺序调用init

self.init(name: "", valueInDollars: 0, serialNumber: nil)