尝试为应该调整字符串的属性制作包装器 [英] Trying to make a wrapper for a property that should adjust a string

问题描述

我有这段代码需要让其他应用重复使用.

I have this code that I need to make reusable by other apps.

此代码显示存在本地化应用程序名称的消息.

This code shows messages where the localized app's name is present.

所以，我有这样的本地化字符串:

So, I have localized strings like this:

"DoYou" = "Do you really want to close $$$?";
"Quit" = "Quit $$$";
"Keep Running" = "Keep $$$ Running";

其中 $$$ 必须在运行时替换为本地化应用的名称.

Where $$$ must be replaced with the localized app's name at run time.

因为我想了解属性包装器，我尝试创建了这个:

Because I want to learn about property wrappers, I have tried to create this one:

extension String {

  func findReplace(_ target: String, withString: String) -> String
  {
    return self.replacingOccurrences(of: target,
                                     with: withString,
                                     options: NSString.CompareOptions.literal,
                                     range: nil)
  }
}


  @propertyWrapper
  struct AdjustTextWithAppName<String> {
    private var value: String?


    init(wrappedValue: String?) {
      self.value = wrappedValue
    }

    var wrappedValue: String? {
      get { value }
      set {
        if let localizedAppName = Bundle.main.localizedInfoDictionary?["CFBundleName"] as? String {
          let replaced = value.findReplace("$$$", withString: localizedAppName)

        }
        value = nil
      }
    }

  }

我在 replaced 行收到此错误:

I get this error on the replaced line:

字符串类型的值?没有名字 findReplace

Value of type String? has no name findReplace

我也试过用这条线

 let replaced = value!.findReplace("$$$", withString: localizedAppName)

同样的错误...

该字符串可能多次包含应用程序名称.这就是为什么我有 String 的扩展.

The string may contain the app's name more than once. This is why I have that extension to String.

推荐答案

为了解决这个问题，你的属性包装器不能有一个名为 String 的泛型类型，因为它掩盖了你的扩展所属的内置类型 String.所以将 struct 声明改为非泛型

To solve this your property wrapper can't have a genereic type named String because that shadows the built-in type String that your extension belongs to. So change the struct declaration to not be generic

@propertyWrapper
struct AdjustTextWithAppName {

或将类型命名为其他名称

or name the type to something else

@propertyWrapper
struct AdjustTextWithAppName<T> {

并修复set方法

set {
    guard let str = newValue, let localizedAppName = Bundle.main.localizedInfoDictionary?["CFBundleName"] as? String else {
        value = nil
     } 

     value = str.findReplace(target: "$$$", withString: localizedAppName)
  }

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