RefreshControl1.swift

import SwiftUI

struct RefreshControl: View {
    var coordinateSpace: CoordinateSpace
    var onRefresh: ()->Void
    @State var refresh: Bool = false
    var body: some View {
        GeometryReader { geo in
            if (geo.frame(in: coordinateSpace).midY > 50) {
                Spacer()
                    .onAppear {
                        if refresh == false {
                            onRefresh() ///call refresh once if pulled more than 50px
                        }
                        refresh = true
                    }
            } else if (geo.frame(in: coordinateSpace).maxY < 1) {
                Spacer()
                    .onAppear {
                        refresh = false
                        ///reset  refresh if view shrink back
                    }
            }
            //Add Animation
        }
    }
}

struct PullToRefreshDemo: View {
    var body: some View {
        ScrollView {
            RefreshControl(coordinateSpace: .named("RefreshControl")) {
                //refresh view here
            }
            Text("Some view...")
        }.coordinateSpace(name: "RefreshControl")
    }
}

struct PullToRefreshDemo_Previews: PreviewProvider {
    static var previews: some View {
        PullToRefreshDemo()
    }
}