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  1. Alternative to instanceType in Swift

    Tuesday, August 23, 2016

    In case you have not noticed, there is no straight forward alternative to using 'instanceType' in Swift. You might have tried using "Self" in place of instanceType like shown in the below code snippet.

    class func instantiateFromStoryboard(storyboardName: String, storyboardId: String) -> Self
    {
    return instantiateFromStoryboardHelper(storyboardName, storyboardId: storyboardId)
    }
    view raw instanceTypeDemo_1.txt hosted with ❤ by GitHub
    But turns out it gives an error saying the object cannot be converted to type Self. I found this elegant solution posted by Martin R on StackOverflow and it uses Generics.

    extension UIViewController
    {
    class func instantiateFromStoryboard(storyboardName: String, storyboardId: String) -> Self
    {
    return instantiateFromStoryboardHelper(storyboardName, storyboardId: storyboardId)
    }
    private class func instantiateFromStoryboardHelper<T>(storyboardName: String, storyboardId: String) -> T
    {
    let storyboard = UIStoryboard(name: storyboardName, bundle: nil)
    let controller = storyboard.instantiateViewControllerWithIdentifier(storyboardId) as! T
    return controller
    }
    }
    let vc = MyViewController.instantiateFromStoryboard("name", storyboardId: "id")
    view raw instanceTypeDemo_2.txt hosted with ❤ by GitHub

    Posted by Adithya at 10:08 AM | Labels: , , , , | |

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