You have to [init `URLSession`][1] with a configuration:

    URLSession(configuration: .default)

or use shared session

    URLSession.shared

  [1]: https://developer.apple.com/library/ios/documentation/Foundation/Reference/NSURLSession_class/#//apple_ref/occ/clm/NSURLSession/sessionWithConfiguration:

In SWIFT 3.0 and up:

            URLSession.shared.dataTask(with: url, completionHandler:
            {
                (data, response, error) in
                
                //Your code
            }).resume()

Aside from the shared session `NSURLSession` must be initialized with one of these two methods

    init(configuration configuration: NSURLSessionConfiguration)


    init(configuration configuration: NSURLSessionConfiguration,
                   delegate delegate: NSURLSessionDelegate?,
                 delegateQueue queue: NSOperationQueue?)


Do the initialization while declaration :-

    var session = URLSession(configuration: .default)

In React-Native, how do I add font borders to Text-components?

I&#39;ve tried using `border` and `shadow{Color, Radius, Opacity, Offset}`, but haven&#39;t gotten that to work. Any suggestions?

How to create text border in React Native?

Is there an Intent to go to my Application&#39;s &quot;App Permissions&quot; screen in Android-M?

I am making my App ready for Android-M and with the new permissions model. I have followed all the steps mentioned in the link

https://developer.android.com/training/permissions/requesting.html

Everything is set and all is good accept that if the user has checked the &quot;Never ask again&quot; button and denied permission, on next launch I want to give the user an option to go to the Application&#39;s &quot;App Permissions&quot; and change the permission himself, if he ever changes his mind. I wanted to make it a bit easier for the non-tech savvy user by providing a button which would take the user straight to my application&#39;s &quot;App Permissions&quot; screen. Is there a way? (It would be much better than giving the user instructions like `Menu` &amp;rarr; `Settings` &amp;rarr; `Applications` &amp;rarr; `Manage Applications` &amp;rarr; select application)

Thank you for helping out!
 

Go to My app&#39;s App Permission screen

When trying to create my own session object `NSURLSession()` and request an url I get an unrecognized selector exception but when I use the shared session `NSURLSession.sharedSession()` everything works fine. How come?

    var url = NSURL(string: &quot;http:/www.google.com&quot;)
    if url != nil {
        //throws unrecognized selector when dataTaskWithURL is called
        let session=NSURLSession()
        session.dataTaskWithURL(url!)
        
       //works
        let sharedSession=NSURLSession.sharedSession()
        sharedSession.dataTaskWithURL(url!)
    }

NSURLSession dataTaskForRequest:completion: unrecognized selector sent to instance

When trying to create my own session object <code>NSURLSession()</code> and request an url I get an unrecognized selector exception but when I use the shared session <code>NSURLSession.sharedSession()</code> everything works fine. How come?
<pre><code class="hljs language-swift">var url = NSURL(string: "http:/www.google.com")
if url != nil {
 //throws unrecognized selector when dataTaskWithURL is called
 let session=NSURLSession()
 session.dataTaskWithURL(url!)
 
 //works
 let sharedSession=NSURLSession.sharedSession()
 sharedSession.dataTaskWithURL(url!)
}
</code></pre>

I have the following enum.

    enum EstimateItemStatus: Printable {
        case Pending
        case OnHold
        case Done
        
        var description: String {
            switch self {
            case .Pending: return &quot;Pending&quot;
            case .OnHold: return &quot;On Hold&quot;
            case .Done: return &quot;Done&quot;
            }
        }
        
        init?(id : Int) {
            switch id {
            case 1:
                self = .Pending
            case 2:
                self = .OnHold
            case 3:
                self = .Done
            default:
                return nil
            }
        }
    }

I need to get all the raw values as an array of strings (like so `[&quot;Pending&quot;, &quot;On Hold&quot;, &quot;Done&quot;]`).

I added this method to the enum.

    func toArray() -&gt; [String] {
        var n = 1
        return Array(
            GeneratorOf&lt;EstimateItemStatus&gt; {
                return EstimateItemStatus(id: n++)!.description
            }
        )
    }

But I&#39;m getting the following error.

&gt; Cannot find an initializer for type &#39;GeneratorOf&lt;EstimateItemStatus&gt;&#39; that accepts an argument list of type &#39;(() -&gt; _)&#39;

Is there is an easier, better or more elegant way to do this?


How to get all enum values as an array

I&#39;m trying to test if a Swift string starts or ends with a certain value. These methods do not exist:

    var str = &quot;Hello, playground&quot;
    str.startsWith(&quot;Hello&quot;) // error
    str.endsWith(&quot;ground&quot;) // error

I would also like to get the prefix and suffix strings. I could find a substring, as is answered [here][1] and [here][2], but ranges are such a pain in Swift.

Is there an easier way to do it?

*(I stumbled across the answer when I was reading [the documentation][3], and since an SO answer didn&#39;t come up for my search terms, I am adding my Q&amp;A here.)*


  [1]: https://stackoverflow.com/questions/24044851/how-do-you-use-string-substringwithrange-or-how-do-ranges-work-in-swift
  [2]: https://stackoverflow.com/questions/28182441/swift-how-to-get-substring-from-start-to-last-index-of-character
  [3]: https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/StringsAndCharacters.html

How to check what a String starts with (prefix) or ends with (suffix) in Swift

I am using Swift 1.2 to develop my iPhone application and I am communicating with a http web service.

The response I am getting is in query string format (key-value pairs) and URL encoded in `.Net`. 

I can get the response, but looking the proper way to decode using Swift.

Sample response is as follows

    status=1&amp;message=The+transaction+for+GBP+12.50+was+successful


Tried following way to decode and get the server response

    // This provides encoded response String
    var responseString = NSString(data: data, encoding: NSUTF8StringEncoding) as! String
    var decodedResponse = responseString.stringByReplacingEscapesUsingEncoding(NSUTF8StringEncoding)!

How can I replace all URL escaped characters in the string?

URL decode in iOS

I have been working with constraints in Swift for iOS, and most of the naming conventions/documentation make things quite self explanatory, but one thing that has recently confused me is two pairs of the NSLayoutXAxisAnchor class:

    leadingAnchor, leftAnchor
along with

    trailingAnchor, rightAnchor

When I have set constraints programmatically in my iOS app, I have found that I can use these totally interchangeably. If I use leadingAnchor, run the app and observe the behavior, and then use leftAnchor, run the app and observe the behavior, it functions exactly the same.

I checked out the documentation from developer.apple.com, and the results are even exactly the same (ignoring the difference in names). For example comparing the leadingAnchor and leftAnchor:


&gt; &quot;Use this anchor to create constraints with the view’s leading edge.
&gt; You can only combine this anchor with a subset of the
&gt; NSLayoutXAxisAnchor anchors. You can combine a leadingAnchor with
&gt; another leadingAnchor, a trailingAnchor, or a centerXAnchor. For more
&gt; information, see NSLayoutAnchor Class Reference.&quot;

compare to:


&gt; &quot;Use this anchor to create constraints with the view’s left edge. You
&gt; can only combine this anchor with a subset of the NSLayoutXAxisAnchor
&gt; anchors. You can combine a leftAnchor with another leftAnchor, a
&gt; rightAnchor, or a centerXAnchor. For more information, see
&gt; NSLayoutAnchor Class Reference.&quot;



Does anyone know if there is any intended difference between these properties?

Difference between leftAnchor and leadingAnchor?

I&#39;ve tried setting attributes in the `XCUIApplication` instance, in my UI Tests `setUp()`

    let app = XCUIApplication()
    app.launchEnvironment = [&quot;testenv&quot; : &quot;testenvValue&quot;]
    app.launchArguments = [&quot;anArgument&quot;]
    app.launch()

in `didFinishLaunch` I&#39;ve tried to show these on screen when I run my UITests
 

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -&gt; Bool {
        if launchOptions != nil {
            for (key, value) in launchOptions! {  
                let alertView = UIAlertView(title: key.description, message: value.description, delegate: nil, cancelButtonTitle: &quot;ok&quot;)
                alertView.show()
            }
        }

But I can&#39;t seem to be able to find the arguments and environment I set. Anyone know how to get a hold of them?

How to access launchEnvironment and launchArguments set in XCUIApplication, running UI tests in XCode?

My Swift / iOS9 framework &#39;viewer_protocol&#39; uses another and external Objective-C framework ([CocoaAsyncSocket](https://github.com/robbiehanson/CocoaAsyncSocket)). I&#39;m using Carthage to build CocoaAsyncSocket. So far everything works fine: In have an example App inside my framework Xcode Project using my framework without any problems.

Now I want to use my Framework in a different Xcode Project - although using Carthage. I include only my Framework as a dependency and Carthage automatically resolves the dependencies to CocoaAsyncSocket. I embedded both frameworks into this new Xcode Project and build my App: Everything works fine here - except one warning I can&#39;t rid off:

    /Users/John/Repositories/my_project/&lt;module-includes&gt;:1:1: 
    Umbrella header for module &#39;my_project&#39; does not include header &#39;GCDAsyncSocket.h&#39;

This is my framework header: 
    
    #import &lt;UIKit/UIKit.h&gt;

    //! Project version number for my_project.
    FOUNDATION_EXPORT double my_projectVersionNumber;

    //! Project version string for my_project.
    FOUNDATION_EXPORT const unsigned char my_projectVersionString[];

    // In this header, you should import all the public headers of your framework     
    using statements like #import &lt;my_project/PublicHeader.h&gt;
    #import &lt;CocoaAsyncSocket/CocoaAsyncSocket.h&gt;

As you can see CocoaAsyncSocket.h is imported. Furthermore inside my framework the CocoaAsyncSocket.h file is included:

[![my framework&#39;s folder](https://s15.postimg.cc/vqx0uj83b/2015_10_03_at_15_51.jpg)](https://postimg.cc/image/vqx0uj83b/)

What I am missing here? I&#39;m using several others external frameworks inside my framework, there&#39;re no warnings for them - all of these external frameworks are written in Swift - CocoaAsyncSocket is pure Objective-C.

This is my frameworks module.modulemap:

     framework module my_project {
       umbrella header &quot;my_project.h&quot;

       export *
       module * { export * }
     }

     module viewer_protocol.Swift {
         header &quot;my_project-Swift.h&quot;
     }




**Update**

I found a solution: Changing the import statement in my framework header from

    #import &lt;CocoaAsyncSocket/CocoaAsyncSocket.h&gt;

to

    #import &quot;CocoaAsyncSocket/CocoaAsyncSocket.h&quot;

Now Xcode finds the header file and the warning disappears.



umbrella header for module &#39;myFramework&#39; does not include header &#39;otherFramework.h&#39;

What I am trying to achieve is perform a `URLSession` request in swift 3. I am performing this action in a separate function (so as not to write the code separately for GET and POST) and returning the `URLSessionDataTask` and handling the success and failure in closures. Sort of like this-

    let task = URLSession.shared.dataTask(with: request) { (data, uRLResponse, responseError) in
                
         DispatchQueue.main.async {
                    
              var httpResponse = uRLResponse as! HTTPURLResponse
                    
              if responseError != nil &amp;&amp; httpResponse.statusCode == 200{
                        
                   successHandler(data!)
                        
              }else{
                        
                   if(responseError == nil){
                         //Trying to achieve something like below 2 lines
                         //Following line throws an error soo its not possible
                         //var errorTemp = Error(domain:&quot;&quot;, code:httpResponse.statusCode, userInfo:nil)
                            
                         //failureHandler(errorTemp)
                            
                   }else{
                            
                         failureHandler(responseError!)
                   }
              }
         }
    }

I do not wish to handle the error condition in this function and wish to generate an error using the response code and return this Error to handle it wherever this function is called from. 
Can anybody tell me how to go about this? Or is this not the &quot;Swift&quot; way to go about handling such situations?

Content Type	Original Author	Original Content on Stackoverflow
Question	Alexey	View Question on Stackoverflow
Solution 1 - Ios	Arsen	View Answer on Stackoverflow
Solution 2 - Ios	pierre23	View Answer on Stackoverflow
Solution 3 - Ios	vadian	View Answer on Stackoverflow
Solution 4 - Ios	Jay Mehta	View Answer on Stackoverflow

NSURLSession dataTaskForRequest:completion: unrecognized selector sent to instance

Ios Problem Overview

Ios Solutions

Solution 1 - Ios

Solution 2 - Ios

Solution 3 - Ios

Solution 4 - Ios

Go to My app's App Permission screen

How to create text border in React Native?

Attributions