Swift中的NSFastEnumeration [英] NSFastEnumeration in Swift

问题描述

我正在尝试将Objective-C项目转换为swift，但我无法找到如何将NSFastEnumeration用于符合NSFastEnumeration的类的对象。

I am trying to convert an Objective-C project to swift, but I am unable to find how to use NSFastEnumeration for an object of a class that conforms to NSFastEnumeration.

以下是ObjC中的代码：

Here is the code in ObjC:

//  get the decode results
id<NSFastEnumeration> results = [info objectForKey: ZBarReaderControllerResults];

ZBarSymbol *symbol = nil;
for(symbol in results)
    // just grab the first barcode
    break;

到目前为止，我试图找到如何做到这一点，但这似乎不起作用，这里是swift代码：

so far I tried to find how to do this, but this doe not seems work, here is the swift code:

var results: ZBarSymbolSet = infoDictionary?.objectForKey(ZBarReaderControllerResults) as ZBarSymbolSet

    var symbol : ZBarSymbol? = nil;

    for symbol in results
    {    //just grab first barcode
        break;
    }

条件错误 - ZBarSymbolSet没有名为的成员发电机

the error comes in for condition - "ZBarSymbolSet" does not have a member named "Generator"

我做错了什么？

这是屏幕截图

Here is the screen shot

推荐答案

经过一段时间在swift框架文件周围探索，我终于找到了这个名为 NSFastGenerator 的好类。 NSSet 和朋友似乎使用相同的生成器。

After a while poking around the swift framework files, I finally found this nice class called NSFastGenerator. NSSet and friends seem to be using the same Generator.

对于 ZBarSymbolSet ，以下是如何将其扩展为支持 for-in 循环：

For ZBarSymbolSet, here's how you'd extend it to support for-in loops:

extension ZBarSymbolSet: SequenceType {
    public func generate() -> NSFastGenerator {
        return NSFastGenerator(self)
    }
}

更新：看起来Swift 2.0的协议扩展为我们解决了这个问题！

Update: Looks like Swift 2.0's protocol extensions fixed this for us!

这篇关于Swift中的NSFastEnumeration的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！