ActivityIndicatorExample.swift

ActivityIndicatorExample.swift

import RxCocoa
import RxSwift
import UIKit

protocol OverlayableViewController: UIViewController {
    var overlayView: UIView! { get set }
    var disposeBag: DisposeBag { get }
}

extension OverlayableViewController {
    private var overlay: Binder<Bool> {
        Binder(overlayView) { v, isLoading in
            v.isHidden = !isLoading
        }
    }
    
    func bindOverlay(to observable: Observable<Bool>) {
        observable
            .asDriver(onErrorJustReturn: false)
            .drive(overlay)
            .disposed(by: disposeBag)
    }
}

class SampleViewController: UIViewController {
    let viewModel = FamilyFontListViewModel()
    let disposeBag = DisposeBag()
    
    @IBOutlet weak var overlayView: UIView! {
        didSet { bindOverlay(to: viewModel.isLoading) }
    }
}
extension FamilyFontListViewController: OverlayableViewController {}