A SwiftUI-like framework for creating cross-platform apps in Swift (5.10+).

To dive right in with SwiftCrossUI, check out the SwiftCrossUI quick start guide.

Note

SwiftCrossUI does not attempt to replicate SwiftUI's API perfectly since that would be a constantly-moving target and SwiftUI has many entrenched Apple-centric concepts. That said, SwiftCrossUI's built-in views and scenes share much of their API surface with their SwiftUI cousins, and over time SwiftCrossUI will likely adopt many of SwiftUI's commonly-used APIs.

Overview

• Community
• Supporting SwiftCrossUI
• Documentation
• Basic example
• Backends

Community

Discussion about SwiftCrossUI happens in the SwiftCrossUI Discord server. Join to discuss the library, get involved, or just be kept up-to-date on progress!

Supporting SwiftCrossUI

If you find SwiftCrossUI useful, please consider supporting me by becoming a sponsor. I spend most of my spare time working on open-source projects, and each sponsorship helps me focus more time on making high quality libraries and tools for the community.

Documentation

Here's the documentation site. SwiftCrossUI is still a work-in-progress; proper documentation and tutorials are on the horizon. Documentation contributions are very welcome!

Basic example

Here's a simple example app demonstrating how easy it is to get started with SwiftCrossUI. For a more detailed walkthrough, check out our quick start guide

import PackageDescription

let package = Package(
    name: "YourApp",
    dependencies: [
        .package(url: "https://github.com/stackotter/swift-cross-ui", branch: "main")
    ],
    targets: [
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "DefaultBackend", package: "swift-cross-ui"),
            ]
        )
    ]
)

Figure 1: Package.swift

import SwiftCrossUI
import DefaultBackend

@main
struct CounterApp: App {
    @State var count = 0

    var body: some Scene {
        WindowGroup("CounterApp") {
            HStack {
                Button("-") { count -= 1 }
                Text("Count: \(count)")
                Button("+") { count += 1 }
            }.padding()
        }
    }
}

Clone the SwiftCrossUI repository to test out this example, and many more;

git clone https://github.com/stackotter/swift-cross-ui
cd swift-cross-ui/Examples
swift run CounterExample

The documentation contains a detailed list of all examples

Backends

SwiftCrossUI has a variety of backends tailored to different operating systems. The beauty of SwiftCrossUI is that you can write your app once and have it look native everywhere. For this reason I recommend using DefaultBackend unless you've got particular constraints.

Tip

Click through each backend name for detailed system requirements and installation instructions.

• DefaultBackend: Adapts to your target operating system. On macOS it uses AppKitBackend, on Windows it uses WinUIBackend, on Linux it uses GtkBackend, and on iOS and tvOS it uses UIKitBackend.
• AppKitBackend: The native macOS backend. Supports all SwiftCrossUI features.
• UIKitBackend: The native iOS & tvOS backend. Supports most SwiftCrossUI features.
• WinUIBackend: The native Windows backend. Supports most SwiftCrossUI features.
• GtkBackend: Works on Linux, macOS, and Windows. Requires gtk 4 to be installed. Supports most SwiftCrossUI features.
• Gtk3Backend: Exists to target older Linux distributions. Requires gtk 3 to be installed. Supports most SwiftCrossUI features. Quite buggy on macOS due to underlying Gtk 3 bugs.

Tip

If you're using DefaultBackend, you can override the underlying backend during compilation by setting the SCUI_DEFAULT_BACKEND environment variable to the name of the desired backend. This is useful when you e.g. want to test the Gtk version of your app while using a Mac. Note that this only works for built-in backends and still requires the chosen backend to be compatible with your machine.