如何在 Swift 结构中正确调用我的 init function？

Question

我当前的代码旨在为加密钱包密钥制作 Sha-256 hash，然后将其打印给我，以便我确认它是否正常工作。 这是我的代码。 顺便说一句，我是初学者，我还有很多东西要学。

import Foundation
import SwiftUI

struct dataManager {
    let characterArray = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","f"]
      @State private var privKey = "0x"
    
        init() {
            for _ in 1...64 {
            privKey += characterArray[Int(arc4random_uniform(16))]
        
            print(privKey)
        }
        
    }

}

问题是 init function 似乎从未被调用过，所以我没有在控制台上打印任何内容。 我尝试除以零以查看是否发生崩溃，但没有发生崩溃，这让我相信它没有被调用或类似的东西。

编辑：我应该补充一点，如果我尝试在 init 之外使用 for 循环，我只会得到一个“预期声明”错误。 我做了一些研究，我认为 init 是我应该在这种情况下使用的。

任何帮助将不胜感激！

Answer 1

正如评论中提到的，@State 仅适用于@State View中。

还有一些其他的小错误，比如在数组中遗漏了"e" 。

这是您的代码的工作版本，尽可能少地修改：

struct DataManager {
    let characterArray = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"]
    var privKey = "0x"
    
    init() {
        for _ in 1...64 {
            privKey += characterArray[Int(arc4random_uniform(16))]
            print(privKey)
        }
    }
}

let manager = DataManager()
print(manager.privKey)

请注意，您可以进一步重构它。 这是另一个本质上有点 Swift 风格的迭代：

struct DataManager {
    let characterArray = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"]
    var privKey = "0x"
    
    init() {
        privKey += (1...64).map { _ in characterArray.randomElement()! }.joined()
    }
}

或者：

struct DataManager {
    var privKey = "0x" + (1...64).map { _ in ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"].randomElement()! }.joined()
}