Adding New SwiftUI Screens into an Existing UINavigationController Hierarchy

Integrating SwiftUI into an existing app can be a powerful way to leverage the advantages of both UIKit and SwiftUI. One common scenario is to add new SwiftUI screens into an existing UINavigationController hierarchy. This allows you to take advantage of the seamless navigation provided by UINavigationController while enjoying the declarative and modern UI building capabilities of SwiftUI.

Step 1: Create a SwiftUI View

The first step is to create a new SwiftUI view that you want to add into the UINavigationController hierarchy. For the purpose of this article, let’s assume that we are adding a new SwiftUI screen called „NewView“.

To create the „NewView“ SwiftUI view, you can create a new Swift file and add the following code:

„`swift
import SwiftUI

struct NewView: View {
var body: some View {
Text(„This is a new SwiftUI screen“)
.font(.largeTitle)
.foregroundColor(.blue)
}
}
„`

In the above code, we have created a simple SwiftUI view with a Text view displaying a message.

Step 2: Create a Hosting Controller

In order to add a SwiftUI view into a UINavigationController hierarchy, we need to wrap it in a UIKit-based view controller called Hosting Controller. The Hosting Controller bridges the gap between UIKit and SwiftUI by providing a container for SwiftUI views in UIKit-based apps.

To create a Hosting Controller for our „NewView“ SwiftUI view, add the following code:

„`swift
import SwiftUI

struct NewView: View {
var body: some View {
Text(„This is a new SwiftUI screen“)
.font(.largeTitle)
.foregroundColor(.blue)
}
}

class NewHostingController: UIHostingController {
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder, rootView: NewView())
}
}
„`

In the above code, we have created a subclass of UIHostingController that initializes itself with the „NewView“ SwiftUI view as the rootView.

Step 3: Integrate the Hosting Controller

Now that we have the Hosting Controller ready, we can integrate it into the existing UINavigationController hierarchy. We need to create a placeholder UIViewController that will host the SwiftUI view controller.

In the existing UIViewController, where you want to push the „NewView“ SwiftUI screen, add the following code:

„`swift
import UIKit
import SwiftUI

class ExistingViewController: UIViewController {
func showNewView() {
let newViewController = NewHostingController()
navigationController?.pushViewController(newViewController, animated: true)
}
}
„`

In the above code, we have created a method named showNewView() that will present the „NewView“ SwiftUI screen. Inside this method, we create an instance of the NewHostingController and push it onto the existing UINavigationController.

Step 4: Trigger the Integration

Now that we have everything in place, we need to trigger the integration by calling the showNewView() method. This can be done through a button action or any other user interaction that you desire.

„`swift
import UIKit
import SwiftUI

class ExistingViewController: UIViewController {
// …

@IBAction func addButtonTapped(_ sender: UIButton) {
showNewView()
}

func showNewView() {
let newViewController = NewHostingController()
navigationController?.pushViewController(newViewController, animated: true)
}
}
„`

In the above code, we have added an IBAction method named addButtonTapped(_:) that triggers the showNewView() method when the UIButton is tapped.

Summary

By following these steps, you can easily add new SwiftUI screens into an existing UINavigationController hierarchy. This allows you to combine the power of UIKit and SwiftUI to create modern and interactive UIs in your app.

Remember that SwiftUI is still evolving, so make sure to keep an eye out for any updates or changes in future versions of iOS and Xcode.