Error: Bool Is Not Convertible to Void:

Error: Bool is not Convertible to Void:

Your block does not have a return statement, therefore the compiler
uses the result of the last statement

UIApplication.sharedApplication().openURL(url)

as return value, which is a Bool and not Void as declared in the block signature.

To solve that problem, just add a return statement:

{ (url: NSURL, oauthToken: String) -> Void in
    UIApplication.sharedApplication().openURL(url)
    return
}

Bool' is not convertible to '() throws - Bool'

Try .flatMapLatest { element -> <RETURN TYPE> in ....
If a flatMap block contains just a single line, return type - isn't necessary.

Why is the return value of std::getline not convertible to bool?

You didn't add #include <istream> to your code, so the compiler doesn't know what istream is and therefore it doesn't know it is convertable to bool.

Add #include <istream> to fix the issue.

Swift 2: Bool' is not convertible to 'BooleanLiteralConvertible'

Swift is confused and giving you an incorrect error message. The problem is that the first parameter is of type [UIViewController]?, so the following should work:

self.pageViewContorller.setViewControllers(viewControllers as? [UIViewController], direction: UIPageViewControllerNavigationDirection.Forward, animated: true, completion: nil)

Or even better, declare viewControllers to be of type [UIViewController] then no casting is needed in the call:

let viewControllers:[UIViewController] = [startVC]
self.pageViewContorller.setViewControllers(viewControllers, direction: UIPageViewControllerNavigationDirection.Forward, animated: true, completion: nil)

block in Swift : return error is not convertible to

It's almost working, but you've got a couple things going wrong here. First of all, you can't redeclare a typealias. Second of all you're calling loadSceneAssetsWithCompletionHandler as a class function when it's set up as an instance function. Note changes:

typealias OnComplete = (Bool) -> ()
class GameController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        GameScene.loadSceneAssetsWithCompletionHandler { success in
            println("2/ yes")
            return
        }
    }

}


class GameScene:  UIViewController {

    func loadSceneAssets() {

    }

    class func loadSceneAssetsWithCompletionHandler( completion:OnComplete ) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
           let gameScene = GameScene()
           gameScene.loadSceneAssets()

            dispatch_async(dispatch_get_main_queue()) {
                println("1/ yes")
                completion(true)
            }
        }
    }
}

How to escape a value with a throw '() throws - Bool' is not convertible to 'Bool'

In your login method, the type of the parameter authenticated is @escaping (_ inner: ThrowableCallBack) -> Void.

So, the closure passed to authenticated takes one parameter of type ThrowableCallBack, which means the parameter auth in your closure is of type ThrowableCallBack, not Bool.

You need to use auth as if try auth() as ThrowableCallBack takes one parameter of type () and throws.

func authenticate() {
    let services = ServiceManager()

    services.login(username: emailField.text!, password: passwordField.text!, authenticated: { auth in
        self.loadingDialog.dismiss(animated: false, completion: {
            do {
                if try auth() {
                    self.performSegue(withIdentifier: "LoginSegue", sender: self)
                }
            } catch RequestError.invalidRequest {
                self.showLoginFailedAlert()
            } catch {
                self.showLoginFailedAlert()
            }
        })
    } )
}

To make this work, you may need to modify the type of authenticated as follows:

func login(username : String, password : String,
           authenticated: @escaping (_ inner: @escaping ThrowableCallBack) -> Void ) {
    //...
}

---

Anyway, closure type taking a parameter of another closure type, is very confusing and you should better re-consider your design.

(ADDITION)

When you get runtime errors saying some main thread things, you may need to use DispatchQueue.main as found in many async examples:

func authenticate() {
    let services = ServiceManager()

    services.login(username: emailField.text!, password: passwordField.text!, authenticated: { auth in
        DispatchQueue.main.async {
            self.loadingDialog.dismiss(animated: false, completion: {
                do {
                    if try auth() {
                        self.performSegue(withIdentifier: "LoginSegue", sender: self)
                    }
                } catch RequestError.invalidRequest {
                    self.showLoginFailedAlert()
                } catch {
                    self.showLoginFailedAlert()
                }
            })
        }
    } )
}

string is not convertible to void

return statusFinale written in blocks, so retrieveStatusInTable function return Void.

When you use asynchronous method, set function return type "Void" and tell result with blocks (completionHandler).

Sample Code:

func retrieveStatusInTable(name: String, completionHandler:((statusFinale: String) -> Void)) {

    // .....

    query.findObjectsInBackgroundWithBlock { (objects:[AnyObject]?, error:NSError?) -> Void in
          // ........
          statusFinale = lastFraseStatus
          completionHandler(statusFinale: statusFinal)
    }
}

Usage:

retrieveStatusInTable("Sample", { (statusFinale) -> Void in
    println(statusFinale)
})

---

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