NSJSONSerialization 在 Playground 中无法按预期工作 [英] NSJSONSerialization not working as expected in a Playground

问题描述

我必须通过 JSON 获取足球比赛时间表，并提取其中一所特定大学的每场比赛的日期.

I have to get football game schedule via JSON and extract date of each game of one of the specific universities.

我试过了:

let url = NSURL(string: "SCHOOL URL")
let request = NSURLRequest(URL: url!)

let session = NSURLSession.sharedSession()

let task = session.dataTaskWithRequest(request){
  (data, response, error) -> Void in

  do{
    let jsonData = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments)

    if let schedule = jsonData["schedule"] as? [[String: AnyObject]]{
    for game in schedule{
      if let date = game["date"] as? String{
         print("\(date)");
      } 
    }
  }

  } catch let error as NSError{
   print("something bad happened!")
  }
}

task.resume()

我正在 Xcode playground 中尝试它，但它没有在打印行打印任何内容.我在 SCHOOL URL 上有合适的网址.

I am trying it in Xcode playground, but it does not print any at print line. And I have appropriate url at SCHOOL URL.

推荐答案

为了在 Xcode Playground 中使用异步操作，您需要将 needsIndefineExecution 设置为 真实.

In order to use asynchronous operations in an Xcode Playground, you need to set needsIndefiniteExecution to true.

在代码顶部添加:

Swift 2

import XCPlayground
XCPlaygroundPage.currentPage.needsIndefiniteExecution = true

Swift 3

import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true

这篇关于NSJSONSerialization 在 Playground 中无法按预期工作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！