我在哪里在Swift中注册ValueTransformer? [英] Where do I register a ValueTransformer in Swift?

问题描述

我正在尝试在Swift中使用ValueTransformer(néNSValueTransformer)，而我的应用程序打开的第一个窗口正在使用它.值转换器必须先通过ValueTransformer.registerValueTransformer(_:forName:)注册，然后才能通过用户界面运行时进行查询.

I'm trying to use a ValueTransformer (né NSValueTransformer) in Swift that is being used by the first window that my application opens. Value transformers need to be registered with ValueTransformer.registerValueTransformer(_:forName:) before they can be queried by the user interface runtime.

NSValueTransformer的文档推荐在+[AppDelegate initialize]中注册值转换器.但是，Swift不允许您覆盖+initialize.我尝试从applicationWillFinishLaunching(_)和applicationDidFinishLaunching(_)注册，但是它们都发生得太晚了，并且我的窗口没有被填满，因为运行时找不到值转换器.

The documentation for NSValueTransformer recommends registering value transformers in +[AppDelegate initialize]. However, Swift doesn't allow you to override +initialize. I tried to register from applicationWillFinishLaunching(_) and applicationDidFinishLaunching(_), but they both happen too late and my window doesn't get filled because the runtime can't find the value transformer.

我应该在哪里注册我的价值转换器?

Where should I register my value transformer?

推荐答案

是的，您可以在AppDelegate中注册值转换器.如果您想要更接近于ObjectiveC +initialize的东西，则可以使用类变量的延迟初始化.例如:

You are right, you can register your value transformers in the AppDelegate. If you want something that closer resembles ObjectiveC's +initialize you can use lazy initialization of a class variable. E.g:

class AppDelegate: NSObject, NSApplicationDelegate {

    static let doInitialize: Void = {
        // register transformers here
    }()

    override init() {
        super.init()
        AppDelegate.doInitialize
    }
}

如果要使转换器的内容更接近实际使用它们的类，则此模式也应适用于除AppDelegate以外的其他类.

This pattern should also work for classes other than the AppDelegate if you want to keep the transformers things closer to the classes that actually use them.

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