iOS 9（Swift 2.0）：无法使用类型为“（NSURL，（_，_，_）throws-> Void）”的参数列表调用“dataTaskwithURL”

Posted 2023-03-08

【中文标题】iOS 9（Swift 2.0）：无法使用类型为“（NSURL，（_，_，_）throws-> Void）”的参数列表调用“dataTaskwithURL”

【英文标题】：iOS 9(Swift 2.0): cannot invoke 'dataTaskwithURL' with an argument list of type '(NSURL, (_, _,_)throws -> Void)'

【发布时间】：2015-09-18 03:17:06

【问题描述】：

我的应用程序在 ios 8 上运行良好，但昨天我升级到 iOS 9 和 Xcode 7，然后我的应用程序崩溃了。错误消息是cannot invoke 'dataTaskwithURL' with an argument list of type '(NSURL, (_, ,)throws -> Void)'。我用谷歌搜索并在这里发现了一个类似的问题，但解决方案并没有真正起作用（解决方案是在代码周围添加 do/catch 块）。谁能帮我解决我的问题？谢谢！！！

这是我的代码

import UIKit
import Foundation
import CoreLocation

class GoogleDataProvider 

    let apiKey = "AIzaSyCQo-clIkek87N99RVh2lmFX9Mu9QPhAtA"
    let serverKey = "AIzaSyBzmv7wPFcPAe1ucy5o6dqaXnda9i9MqjE"
    var photoCache = [String:UIImage]()
    var placesTask = NSURLSessionDataTask()
    var session: NSURLSession 
    return NSURLSession.sharedSession()

    func fetchPlacesNearCoordinate(coordinate: CLLocationCoordinate2D, radius:Double, types:[String],keyword:String, completion: (([GooglePlace]) -> Void)) -> ()
 
    var urlString = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?key=\(serverKey)&location=\(coordinate.latitude),\(coordinate.longitude)&radius=\(radius)&keyword=\(keyword)&rankby=prominence&sensor=true"
    let typesString = types.count > 0 ? types.joinWithSeparator("|") : "food"
    urlString += "&types=\(typesString)"
    urlString = urlString.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!

    if placesTask.taskIdentifier > 0 && placesTask.state == .Running 
    placesTask.cancel()
  

    UIApplication.sharedApplication().networkActivityIndicatorVisible = true

do

 //******************Here's the line that displays error

placesTask = session.dataTaskWithURL(NSURL(string: urlString)!) 
    (data, response, error) -> Void in
UIApplication.sharedApplication().networkActivityIndicatorVisible = false
  var placesArray = [GooglePlace]()
  if let json = try NSJSONSerialization.JSONObjectWithData(data!, options:[]) as? NSDictionary 
    if let results = json["results"] as? NSArray   
      for rawPlace:AnyObject in results 
        let place = GooglePlace(dictionary: rawPlace as! NSDictionary, acceptedTypes: types)
        placesArray.append(place)
        if let reference = place.photoReference 
          self.fetchPhotoFromReference(reference)  image in
            place.photo = image
          
        
      
    
  
  dispatch_async(dispatch_get_main_queue()) 
    completion(placesArray)
  

    catch


    placesTask.resume()


    func fetchDirectionsFrom(from: CLLocationCoordinate2D, to: CLLocationCoordinate2D, completion: ((String?) -> Void)) -> ()
 
    let urlString = "https://maps.googleapis.com/maps/api/directions/json?key=\(serverKey)&origin=\(from.latitude),\(from.longitude)&destination=\(to.latitude),\(to.longitude)&mode=walking"

    UIApplication.sharedApplication().networkActivityIndicatorVisible = true

do
//******************************Here too ****************************
    session.dataTaskWithURL(NSURL(string: urlString)!) 
    (data, response, error) -> Void in
  UIApplication.sharedApplication().networkActivityIndicatorVisible = false
  var encodedRoute: String?
  if let json = try NSJSONSerialization.JSONObjectWithData(data!, options:[]) as? [String:AnyObject] 
    if let routes = json["routes"] as AnyObject? as? [AnyObject] 
      if let route = routes.first as? [String : AnyObject] 
        if let polyline = route["overview_polyline"] as AnyObject? as? [String : String] 
          if let points = polyline["points"] as AnyObject? as? String 
            encodedRoute = points
          
        
      
    
  
  dispatch_async(dispatch_get_main_queue()) 
    completion(encodedRoute)
  
.resume()
catch

    
  
  

对不起，这是我第一次发布代码风格有点混乱对不起缩进混乱:)

再次感谢！！！

【问题讨论】：

有一天，Swift 编译器会准确地告诉我们哪个参数的类型错误...... 但不是今天！ i> 说真的，有时即使在查看文档中的方法声明后也并不明显。尤其是在从 Swift 1.2 到 2.0 的过渡期间...

【参考方案1】：

dataTaskWithURL:completionHandler: 不抛出错误。

将 do 和 catch 放入 dataTaskWithURL 方法中。

例如：

    session.dataTaskWithURL(NSURL(string: urlString)!) 
        (data, response, error) -> Void in
        UIApplication.sharedApplication().networkActivityIndicatorVisible = false
        var encodedRoute: String?
        do 
            if let json = try NSJSONSerialization.JSONObjectWithData(data!, options:[]) as? [String:AnyObject] 
                if let routes = json["routes"] as AnyObject? as? [AnyObject] 
                    if let route = routes.first as? [String : AnyObject] 
                        if let polyline = route["overview_polyline"] as AnyObject? as? [String : String] 
                            if let points = polyline["points"] as AnyObject? as? String 
                                encodedRoute = points
                            
                        
                    
                
            
         catch 

        

        dispatch_async(dispatch_get_main_queue()) 
            completion(encodedRoute)
        
    .resume()