RxSwift minimal Observable.create example

Question

Currently I am trying to get RxSwift working. And I want to create a custom Observable. But I think I am doing something wrong.

I have distilled what I do to this minimal sample:

import Foundation import RxSwift  class Example {      let exampleObservable : Observable<String> = Observable.create { (observer) in         observer.on(.Next("hello"))         observer.on(.Completed)          return AnonymousDisposable { }     }      let exampleObserver : AnyObserver<String>?      func run()     {         self.exampleObserver = exampleObservable.subscribeNext({ (text) -> Void in             print(text)         })       }  }  let ex = Example() ex.run() 

Is this correct? In the run method, the subscribeNext method is autocompleted that way by XCode.

But when I run it I get the following compilation error:

Cannot Invoke 'substribeNext' with an argument list of type ((String) -> Void) 

Answer 1

You may use RxExamples for better understanding RxSwift. I found it in RxSwift repo. It helped me in understanding RxSwift.

Ok, let's try to send simple request using Alamofire and RxSwift. First we write request function:

 func getApi() -> Observable<AnyObject?> {     return create{ observer in         let request = Alamofire.request(.GET, "http://someapiurl.com", parameters: nil)             .response(completionHandler:  { request, response, data, error in                 if ((error) != nil) {                     observer.on(.Error(error!))                 } else {                     observer.on(.Next(data))                     observer.on(.Completed)                 }             });         return AnonymousDisposable {             request.cancel()         }     } } 

getApi() method sends request and gets response from server using Alamofire. I used RxSwift observer for sending success or errors messages. Second we must call this function. You can use rx_tap for button:

class ViewController: UIViewController {          var disposeBag = DisposeBag()          override func viewDidLoad() {             super.viewDidLoad()               getApi()                 // Set 3 attempts to get response                 .retry(3)                 // Set 2 seconds timeout                 .timeout(2, MainScheduler.sharedInstance)                 // Subscribe in background thread                 .subscribeOn(Dependencies.sharedDependencies.backgroundWorkScheduler)                 // Observe in main thread                 .observeOn(Dependencies.sharedDependencies.mainScheduler)                 // Subscribe on observer                 .subscribe(                     onNext: { data in                         do {                             let post = try NSJSONSerialization.JSONObjectWithData(data as! NSData, options: []) as! NSDictionary                             print(post)                         } catch  {                             print(NSString(data: data as! NSData, encoding: NSUTF8StringEncoding))                             return                         }                     },                     onError: { error in                         print(error)                     },                     onCompleted: {                         print("Completed")                     },                     onDisposed: {                         print("Disposed")                     }                 )                 .addDisposableTo(disposeBag)         }     } 

This is my simple example. Hope this helps you. ReactiveX is a huge opportunities. Good luck in learn RxSwift!

Answer 2

This implementation has changed slightly with Swift 3:

    func observableFunc() -> Observable<Bool> {         return Observable.create { observer in              self.apiClient.fetchData(callback: { results, error in                  if let error = error {                     observer.onError(error)                 }                  if let results = results {                     observer.onNext(true)                     observer.onCompleted()                 }             })             return Disposables.create()         }     }