Refreshable View / ScrollView with a custom UIView

SwiftUICustomRefreshControl.swift

//
//  SwiftUICustomRefreshControl.swift
//  SwiftUICustomRefreshControl
//
//  Created by Wilson Munoz on 23/08/22.
//

import SwiftUI
import UIKit

struct ContentView: View {
    var body: some View {
        RefreshableScrollView {
            Text("Scrollable content")
                .padding()
        } onRefresh: {
            //Call a refresh, usually a ViewModel
            print("refresh called")
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}


//Make a ScrollView or any content refreshable, putting inside a List (iOS15+), follow links for the source of the code
//https://stackoverflow.com/questions/71562594/swiftui-refreshable-pull-to-refresh-is-not-working-at-scrollview
//https://github.com/globulus/swiftui-pull-to-refresh
struct RefreshableScrollView<Content: View>: View {
    
    // MARK: - Properties
    var content: Content
    var onRefresh: () -> Void
    
    //MARK: - Init
    public init(content: @escaping () -> Content, onRefresh: @escaping () -> Void) {
        self.content = content()
        self.onRefresh = onRefresh
    }
    
    // MARK: - body
    public var body: some View {
        List {
            content
                .listRowSeparatorTint(.clear)
                .listRowBackground(Color.clear)
                .listRowInsets(EdgeInsets(top: 0, leading: 0, bottom: 0, trailing: 0))
        }
        .listStyle(.plain)
        .refreshable {
            onRefresh()
        }
        .onAppear{
            
            //Hide the default refresh controller, attach our uiView
            //Because is a singleton it wont be added several times
            //You can always expand your singleton to be hidden, animated, removed, etc.
            UIRefreshControl.appearance().tintColor = .clear
            UIRefreshControl.appearance().addSubview(SingletonView.shared)
          
        }
        
        
        
    }

}

//Singleton Class View
class SingletonView: UIView {
    
    // Singleton instance
        static let shared : UIView = SingletonView.sharedInstance(size: CGSize(width: 20, height: 20))

        // You can modify argument list as per your need.
        class private func sharedInstance(size : CGSize)->UIView {
            //Putting the view in the middle, but the details falls on you.
            let view = UIView(frame: CGRect(x: (UIScreen.main.bounds.width / 2) - size.width/2, y: 0, width: size.width, height: size.height))
            //just so you can see something
            view.layer.backgroundColor = UIColor.red.cgColor
            return view
        }
    
}