README.md

HostingSample

HostingSample is an iOS project that provides examples and implementation for a custom view called HostingView. The purpose of HostingView is to facilitate the interoperability of SwiftUI views in UIKit-based apps. Developers can seamlessly integrate SwiftUI views directly within any UIView using HostingView.

Usage

Using HostingView is straightforward. Here's a basic example of how to integrate a SwiftUI view into a UIKit-based project:

import UIKit
import SwiftUI

class MyViewController: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    let hostingView = HostingView(rootView: MySwiftUIView())
    view.addSubview(hostingView)
    hostingView.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      hostingView.topAnchor.constraint(equalTo: view.topAnchor),
      hostingView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
      hostingView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
      hostingView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
    ])
  }
}

struct MySwiftUIView: View {
  var body: some View {
    Text("Hello, SwiftUI!")
      .font(.title)
      .padding()
      .background(Color.blue)
      .foregroundColor(.white)
      .cornerRadius(10)
  }
}

Examples

Example	Description	Preview
Overview	An overview of the examples included in this project.
Static SwiftUI Elements	Demonstrates how to use static SwiftUI elements like Text, Image, and Button.
Dynamic SwiftUI Elements	Demonstrates how to use SwiftUI elements with dynamic values
Emoji Picker: Popover	Demonstrates how to present a custom emoji picker UIViewController as an inline popover.
Emoji Intensifies: Parallax	Demonstrates an example of a parallax effect on a selected emoji.

This project includes a few examples to demonstrate the capabilities of HostingView. The examples are as follows:

• Basic Example: Demonstrates how to integrate a simple SwiftUI view into a UIKit-based project.
  • Static SwiftUI Elements: Shows how to use static SwiftUI elements like Text, Image, and Button.
    • Static SwiftUI View within a UIView: Use a HostingView to nest a SwiftUI element within a UIView.
  • Dynamic SwiftUI Elements: Shows how to use dynamic SwiftUI elements like List and ForEach.
    • Using @Observable: For iOS 17+ minimum deployments.
    • Using an ObservableObject: ObservableObject will generally trigger as many View updates for a single property changing as there are Published properties. This means that things like FocusState, dismiss/presents, popovers, and so on will behave erratically. Proceed with extreme care and caution.
    • Using @Perceptible: @Perceptible is a third-party backport of @Observable that allows us to deploy @Observable behaviors on versions earlier than iOS 17. If you can include a third-party dependency and your deploy-target is currently lower than iOS 17, this is the recommended approach.
• Emoji Views: These examples demonstrate how to use a custom Emoji Picker view – modeled after the iOS emoji keyboard – to select and display emojis in a mixed UIKit/SwiftUI environment. The EmojiCollectionViewController is the custom view controller that displays emojis and allows users to select them. This view is integrated into a SwiftUI View in order to build up a more complex UI. These SwiftUI Views are then integrated into a UIKit-based project using HostingView.
  • Presentation: inline popover: Demonstrates how to present the emoji picker as an inline popover.
    • Stock popover modifier: Use the stock modifier with presentationCompactAdaptation to display as a popover on iPhones. Available for iOS 16.4+ deployments.
    • Custom popover_backport modifier: Use the popover_backport modifier if your deploy target is less than iOS 16.4.
  • Emoji Intensifies: Parallax: Demonstrates an example of a parallax effect on a selected emoji.
    • Animating Emojis, with selection: On a device, this appears as a parallax effect. As we don't have data from CoreMotion on the simulator, we've mocked values coming from CoreMotion as random numbers over a range. The effect on a simulator is an "intensifies" animation. More importantly, this demo showcases how we can continue to utilize the EmojiCollectionViewController's filtering even though we don't have access to its searchController.