知道使用异步方法对数组的迭代何时完成 [英] Know when an iteration over array with async method is finished

问题描述

假设我有一个字符串数组，我调用了一个从它返回一个 int 的异步方法.我想知道我的 int 数组中何时有这些 int 值.

Lets say i have an array of strings, and i call an async method that returns an int from it. I want to know when i have those int values in my array of ints.

let rndStrings = ["a", "b", "c"]
var rndInts = [Int]()
rndStrings.forEach { rndString in 
   someAsyncMethod { intResult in
     rndInts.append(intResult)
   }
}

我想等到 rndInts 拥有所有 3 个值

I want to wait until rndInts has all 3 values

推荐答案

不要等待.通过 DispatchGroup 获得通知.

let rndStrings = ["a", "b", "c"]
let group = DispatchGroup()
var rndInts = [Int]()
rndStrings.forEach { rndString in 
   group.enter()
   someAsyncMethod { intResult in
     rndInts.append(intResult)
     group.leave()
   }
}
group.notify(queue: DispatchQueue.main) {
   print("finished")
}

这篇关于知道使用异步方法对数组的迭代何时完成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！