Swift: Get all subviews of a specific type and add to an array

Question

I have a custom class of buttons in a UIView that I\'d like to add to an array so that they\'re easily accessible. Is there a way to get all subviews of a specific class and

Answer 1

For this case, I think we could use Swift's first.where syntax, which is more efficient than filter.count, filter.isEmpty.

Because when we use filter, it will create a underlying array, thus not effective, imagine we have a large collection.

So just check if a view's subViews collection contains a specific kind of class, we can use this

let containsBannerViewKind = view.subviews.first(where: { $0 is BannerView }) != nil

which equivalent to: find me the first match to BannerView class in this view's subViews collection. So if this is true, we can carry out our further logic.

Reference: https://github.com/realm/SwiftLint/blob/master/Rules.md#first-where

Answer 2

The filter function using the is operator can filter items of a specific class.

let myViews = view.subviews.filter{$0 is MyButtonClass}

MyButtonClass is the custom class to be filtered for.

To filter and cast the view to the custom type use compactMap

let myViews = view.subviews.compactMap{$0 as? MyButtonClass}

Answer 3

Here you go

    extension UIView {

    /** This is the function to get subViews of a view of a particular type 
*/
    func subViews<T : UIView>(type : T.Type) -> [T]{
        var all = [T]()
        for view in self.subviews {
            if let aView = view as? T{
                all.append(aView)
            }
        }
        return all
    }


/** This is a function to get subViews of a particular type from view recursively. It would look recursively in all subviews and return back the subviews of the type T */
        func allSubViewsOf<T : UIView>(type : T.Type) -> [T]{
            var all = [T]()
            func getSubview(view: UIView) {
                if let aView = view as? T{
                all.append(aView)
                }
                guard view.subviews.count>0 else { return }
                view.subviews.forEach{ getSubview(view: $0) }
            }
            getSubview(view: self)
            return all
        }
    }

You can call it like

let allSubviews = view.allSubViewsOf(type: UIView.self)
let allLabels = view.allSubViewsOf(type: UILabel.self)

Answer 4

func allSubViews(views: [UIView]) {
    for view in views {
        if let tf = view as? UITextField {
             // Do Something
        }
        self.allSubViews(views: view.subviews)
    }
}

self.allSubViews(views: self.view.subviews)

Answer 5

So many of the answers here are unnecessarily verbose or insufficiently general. Here's how to get all subviews of a view, at any depth, that are of any desired class:

extension UIView {
    func subviews<T:UIView>(ofType WhatType:T.Type) -> [T] {
        var result = self.subviews.compactMap {$0 as? T}
        for sub in self.subviews {
            result.append(contentsOf: sub.subviews(ofType:WhatType))
        }
        return result
    }
}

How to use:

let arr = myView.subviews(ofType: MyButtonClass.self)