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iOS Build a Weather App with Swift Managing Complexity Callback Methods With Closures

Posted by kevin11
kevin11
2,535 Points

Callback methods with closure?

I have been struggling with this challenge for a while now and can't seem to find a way to do it. This is the objective:

We're writing an app to fetch the most recent blog posts from the Treehouse blog. This requires making a network request using asynchronous methods that execute in the background. For that we need a closure. Create a method called fetchTreehouseBlogPosts, that has a single parameter - a completion handler. The closure has three parameters: a data object containing the results of the request as type NSData!, the HTTP response object from our request as type NSURLResponse!, an error object as type NSError!, and a return type of void. Note: If you prefer to use a typealias to make the method signature clear, name it BlogPostCompletion

It is really long and a little confusing. I can't figure out how to do it but I gave it my best shot. Please help solve the challenge. Here is my code:

Callbacks.swift 
import Foundation

// Add your code below

func fetchTreehouseBlogPosts(completion: (NSURLResponse! -> Void)) (completionHandler {
let data, let response, let error) in
}

1 Answer

alipayne
alipayne
1,902 Points
alipayne
alipayne
1,902 Points

Already answered: https://teamtreehouse.com/forum/i-am-at-a-loss-with-this-quiz-i-create-typealias-blogpostcompletion-nsdata-nsurlresponse-nserror-void

alipayne
alipayne
1,902 Points

but jut in case:

import Foundation

// Add your code below typealias BlogPostCompletion = ((NSData!, NSURLResponse!, NSError!) -> Void)

// Add your code below func fetchTreehouseBlogPosts (completion: BlogPostCompletion) { let blogURL = NSURL(string: "http://blog.teamtreehouse.com/api/") let requestURL = NSURL(string: "get_recent_summary/?count=20", relativeToURL: blogURL)

let request = NSURLRequest(URL: requestURL!)

let config = NSURLSessionConfiguration.defaultSessionConfiguration() let session = NSURLSession(configuration: config)

// Add your code between the comments let dataTask: NSURLSessionDataTask = session.dataTaskWithRequest(request) {(data, response, error) in return completion(data, response, error)

} dataTask.resume() }