session.dataTask 调用错误中的 Swift5 额外参数“completionHandler”

Posted 2023-02-23

【中文标题】session.dataTask 调用错误中的 Swift5 额外参数“completionHandler”

【英文标题】：Swift5 Extra argument 'completionHandler' in call error with session.dataTask

【发布时间】：2020-08-20 07:50:06

【问题描述】：

我正在尝试制作一些天气应用程序 但是有一些问题 错误是“调用中的额外参数'completionHandler'” 我应该怎么做才能解决它？？ enter image description here

    import Foundation
    
    struct WeatherManager 
        let weatherURL = "http://api.openweathermap.org/data/2.5/weather?APPID=sdfkjskfjsfjskflskflsjklfjf&units=metric"
        
        func fetchWeather(cityName: String) 
           let urlStirng = "\(weatherURL)&q=\(cityName)"
            performRequest(urlString: urlStirng)
        
        
        func performRequest(urlString: String) 
            //1. Create a URL
            if let url = URL(string: urlString) 
                
                //2. Create a URL Session
                let session = URLSession(configuration: .default)
                
                //3. Give the session a task
                let task = session.dataTask(with: url, completionHandler: handle(data:response:error:))
                
                //4. Start the task
                task.resume()
                
            
        
        
        func handle(data: Data?, response: URLSession?, error: Error?) 
            
        
        
    

【问题讨论】：

请张贴代码...而不是图片...

【参考方案1】：

检查以下代码：

func performRequest(urlString: String) 

    //1. Create a URL
    if let url = URL(string: urlString) 
        
        //2. Create a URL Session
        let session = URLSession(configuration: .default)
        
        //3. Give the session a task
        let task = session.dataTask(with: url, completionHandler: handle)
        
        //4. Start the task
        task.resume()
    


func handle(data: Data?, response: URLResponse?, error: Error?) 

对于response，您需要将URLResponse 而不是URLSession 传递给handle，并且您不必编写参数名称，因为您将handle 函数作为参数传递给dataTask.