SwiftUI navigation

gistfile1.swift

import SwiftUI

struct MainView: View {
    
    @State var isPresent = true
    @State var showFullScreen = false
    @State var showModal = false

    var body: some View {
        ZStack {
            if !showFullScreen {
                BlueScreen(showFullScreen: self.$showFullScreen, showModal: self.$showModal)
            } else {
                FullScreen(showFullScreen: self.$showFullScreen)
            }
        }
    }
}

struct SoundSheet : View {

    @Binding var showCallSreen: Bool
    @Environment(\.presentationMode) var presentationMode

    let dg = DragGesture()

    var body: some View {

        ZStack {
            Rectangle()
                .fill(Color.yellow)
                .frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
                .highPriorityGesture(dg)

            VStack {
                Button("Dismiss YellowScreen") {
                    self.presentationMode.wrappedValue.dismiss()
                }
                Button("Show FullScreenView") {
                    self.showCallSreen.toggle()
                }
            }

        }
    }
}

struct FullScreen: View {

    @Binding var showFullScreen: Bool

    var body: some View {
        VStack {
            Rectangle()
                .fill(Color.red)
                .frame(width: 400, height: 400)
            VStack {
                Button(action: {
                    withAnimation(.linear) {
                        self.showFullScreen.toggle()
                    }
                }) {
                    Text("Back to Blue Screen")
                }
            }
        }

    }
}

struct BlueScreen: View {
    @Binding var showFullScreen: Bool
    @Binding var showModal: Bool

    var body: some View {
        VStack {
            Button(action: {
                self.showModal.toggle()

            }) {
                Text("Show Yellow screen")
            }
            Rectangle()
                .fill(Color.blue)
                .frame(width: 400, height: 400)
            .sheet(isPresented: self.$showModal) {
                SoundSheet(showCallSreen: self.$showFullScreen)
            }

        }
    }
}