TextAlert

TextAlert.swift

//
//  ContentView.swift
//
//  Created by Chris Eidhof on 20.04.20.
//  Copyright © 2020 objc.io. All rights reserved.
//
// Updated by Anton Sokolchenko for Xcode 12 Beta 4
import SwiftUI
import UIKit

extension UIAlertController {
	convenience init(alert: TextAlert) {
		self.init(title: alert.title, message: nil, preferredStyle: .alert)
		addTextField { $0.placeholder = alert.placeholder }
		addAction(UIAlertAction(title: alert.cancel, style: .cancel) { _ in
			alert.action(nil)
		})
		let textField = self.textFields?.first
		addAction(UIAlertAction(title: alert.accept, style: .default) { _ in
			alert.action(textField?.text)
		})
	}
}



struct AlertWrapper<Content: View>: UIViewControllerRepresentable {
	@Binding var isPresented: Bool
	let alert: TextAlert
	let content: Content

	func makeUIViewController(context: UIViewControllerRepresentableContext<AlertWrapper<Content>>) -> UIHostingController<Content> {
		UIHostingController(rootView: content)
	}

	final class Coordinator {
		var alertController: UIAlertController?
		init(_ controller: UIAlertController? = nil) {
			self.alertController = controller
		}
	}

	func makeCoordinator() -> Coordinator {
		return Coordinator()
	}


	func updateUIViewController(_ uiViewController: UIHostingController<Content>, context: UIViewControllerRepresentableContext<AlertWrapper<Content>>) {
		uiViewController.rootView = content
		if isPresented && uiViewController.presentedViewController == nil {
			var alert = self.alert
			alert.action = {
				self.isPresented = false
				self.alert.action($0)
			}
			context.coordinator.alertController = UIAlertController(alert: alert)
			uiViewController.present(context.coordinator.alertController!, animated: true)
		}
		if !isPresented && uiViewController.presentedViewController == context.coordinator.alertController {
			uiViewController.dismiss(animated: true)
		}
	}
}

public struct TextAlert {
	public var title: String
	public var placeholder: String = ""
	public var accept: String = "OK"
	public var cancel: String = "Cancel"
	public var action: (String?) -> ()
}

extension View {
	public func alert(isPresented: Binding<Bool>, _ alert: TextAlert) -> some View {
		AlertWrapper(isPresented: isPresented, alert: alert, content: self)
	}
}

struct AlertContentView: View {
	@State var showsAlert = false
	var body: some View {
		VStack {
			Text("Hello, World!")
			Button("alert") {
				self.showsAlert = true
			}
		}
		.alert(isPresented: $showsAlert, TextAlert(title: "Title", action: {
			print("Callback \($0 ?? "<cancel>")")
		}))
	}
}

struct AlertContentView_Previews: PreviewProvider {
	static var previews: some View {
		AlertContentView()
	}
}