从url获取图片时出错？

Question

let defaultConfiguration = URLSessionConfiguration.default 
    let operationQueue = OperationQueue.main 
    let defaultSession = URLSession(configuration: defaultConfiguration, delegate: self, delegateQueue: operationQueue) 
    if let url = URL(string: "https://newsapi.org/v1/articles?source=abc-news-au&sortBy=top&apiKey=47d2ce48babd47b1bc391b426b89ca23") 
    { 
     (defaultSession.dataTask(with: url) { (data, response, error) in 

      if error != nil{ 
       return 
      } 
      do { 
       let resultJson = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:AnyObject] 
       if var dataDictionary = resultJson { 
        // dataDictionary["access_token"] as AnyObject 
        self.dataArray = dataDictionary["articles"] as! [Any] 
        var dataDictionary22 = self.dataArray[0] as! [String: Any] as [String : AnyObject] 
        let url = URL(string: 
         "\(String(describing: dataDictionary22["urlToImage"]!))") 
        print("url -> \(String(describing: url!))") 
        let task = URLSession.shared.dataTask(with: url!) { data, response, error in 
         guard let data = data, error == nil else { 
          return 
         } 


          self.imageView.image = UIImage(data: data) 

        } 

        task.resume() 

       } 

      } catch { 
       print("Error -> \(error)") 
      } 

     }).resume() 
    } 

我试图通过nsurlsession获得从开放API的新闻更新，它有dictionary->阵列 - > dictionary->在关键的“urlToImage” 但IAM越来越像URL，但http://www.abc.net.au/news/image/8968140-1x1-700x700.jpg数据中没有得到的图像文件是空任何一个可以最小化代码长度并解决我的问题

Answer 1

使用这段代码，您可以成功解析该特定的URL响应，我已经在Playground中进行了测试。

这个："\(String(describing: dataDictionary22["urlToImage"]!))"不是从AnyObject得到String的方法，你应该使用条件转换。

if let url = URL(string: "https://newsapi.org/v1/articles?source=abc-news-au&sortBy=top&apiKey=47d2ce48babd47b1bc391b426b89ca23"){ 
    URLSession.shared.dataTask(with: url, completionHandler: { data, response, error in 
     guard error == nil, let data = data else { 
      print(error!);return 
     } 
     guard let resultJson = (try? JSONSerialization.jsonObject(with: data)) as? [String:Any] else { 
      return 
     } 
     print(resultJson) 
     guard let articles = resultJson["articles"] as? [[String:Any]], let firstArticle = articles.first else { return } 
     guard let imageUrlString = firstArticle["urlToImage"] as? String, let imageUrl = URL(string: imageUrlString) else { return } 
     URLSession.shared.dataTask(with: imageUrl, completionHandler: { data, response, error in 
      guard error == nil, let data = data else { 
       print(error!);return 
      } 
      let image = UIImage(data: data) 
      DispatchQueue.main.async { 
       self.imageView.image = image 
      } 
     }).resume() 
    }).resume() 
} 

如果你想获得的所有文章图片（在你的问题，你只解析第一个），只是改变guard let articles = resultJson["articles"] as? [[String:Any]], let firstArticle = articles.first else { return }以下几点：

for article in articles { 
    guard let imageUrlString = article["urlToImage"] as? String, let imageUrl = URL(string: imageUrlString) else { return } 
    URLSession.shared.dataTask(with: imageUrl, completionHandler: { data, response, error in 
     guard error == nil, let data = data else { 
      print(error!);return 
     } 
     let image = UIImage(data: data) 
     //use the image 
    }).resume() 
}