swiftui

Documentation

Overview

Package swiftui loads app-owned Swift packages that expose SwiftUI content to AppKit.

The intended workflow is:

1. Put your SwiftUI code in a Swift package that builds a dynamic library.
2. Export an Objective-C-visible factory class from that package.
3. Optionally prebuild a universal dylib with go generate.
4. Optionally embed that dylib in your Go binary.
5. Use this Go package to load the embedded dylib first, then `Dir/lib<Product>.dylib`, then fall back to building the Swift package on demand from source.

The default contract expects the Swift factory class to provide `newRootViewController` and `newRootView` class methods. Those selectors use Cocoa's "new" ownership convention, so the Go caller owns the returned object and must call Release when finished with it.

Example Swift package:

import SwiftUI
import AppKit

struct ContentView: View {
    var body: some View {
        Text("Hello from SwiftUI").padding(24)
    }
}

@objc(ExampleUIBridge)
public final class ExampleUIBridge: NSObject {
    @objc public static func newRootViewController() -> NSViewController {
        NSHostingController(rootView: ContentView())
    }

    @objc public static func newRootView() -> NSView {
        NSHostingView(rootView: ContentView())
    }
}

Example Go usage:

bridge, err := swiftui.Open(swiftui.Config{
	Dir:          "/path/to/ui",
	Product:      "ExampleUI",
	FactoryClass: "ExampleUIBridge",
	EmbeddedLibrary: embeddedExampleUI(),
})
if err != nil {
	log.Fatal(err)
}
controller, err := bridge.NewViewController()
if err != nil {
	log.Fatal(err)
}
defer controller.Release()
window.SetContentViewController(controller)

Typical embedding setup:

//go:generate go run ./ui/generate.go

//go:build swiftui_embed
//go:embed ui/libExampleUI.dylib
var exampleUIDylib []byte

Callers should lock the main goroutine to the main thread before creating or using AppKit objects returned by this package.

Index

• type Bridge
  • func Open(cfg Config) (*Bridge, error)
  • func (b *Bridge) NewView() (*HostedView, error)
  • func (b *Bridge) NewViewController() (*HostedViewController, error)
  • func (b *Bridge) ProductPath() string
• type Config
• type HostedView
  • func (v *HostedView) Release()
• type HostedViewController
  • func (c *HostedViewController) Release()

Types

type Bridge

type Bridge struct {
	// contains filtered or unexported fields
}

Bridge loads a Swift package product and resolves its SwiftUI factory class.

func Open

func Open(cfg Config) (*Bridge, error)

Open builds and loads the Swift package product, then resolves the factory class in the Objective-C runtime.

func (*Bridge) NewView

func (b *Bridge) NewView() (*HostedView, error)

NewView asks the Swift factory class for a retained NSView.

func (*Bridge) NewViewController

func (b *Bridge) NewViewController() (*HostedViewController, error)

NewViewController asks the Swift factory class for a retained NSViewController.

func (*Bridge) ProductPath

func (b *Bridge) ProductPath() string

ProductPath returns the loaded dylib path.

type Config

type Config struct {
	// Dir is the Swift package directory containing Package.swift.
	Dir string

	// Product is the dynamic library product name from Package.swift.
	Product string

	// FactoryClass is the Objective-C runtime name of the exported factory class.
	FactoryClass string

	// EmbeddedLibrary is an optional prebuilt dylib payload. When present, Open
	// materializes and loads this dylib before falling back to building from
	// source in Dir.
	EmbeddedLibrary []byte

	// EmbeddedLibraryName is the filename used when materializing
	// EmbeddedLibrary. Defaults to lib<Product>.dylib.
	EmbeddedLibraryName string

	// PrebuiltLibraryPath is an optional on-disk dylib path. When empty and Dir
	// is set, Open also checks Dir/lib<Product>.dylib before falling back to
	// swift build.
	PrebuiltLibraryPath string

	// ViewControllerSelector names the class method returning a retained
	// NSViewController. Defaults to "newRootViewController".
	ViewControllerSelector string

	// ViewSelector names the class method returning a retained NSView.
	// Defaults to "newRootView".
	ViewSelector string
}

Config describes an app-owned Swift package that exposes SwiftUI content.

type HostedView

type HostedView struct {
	appkit.NSView
	// contains filtered or unexported fields
}

HostedView owns a retained NSView returned by the Swift package factory.

func (*HostedView) Release

func (v *HostedView) Release()

Release releases the retained NSView.

type HostedViewController

type HostedViewController struct {
	appkit.NSViewController
	// contains filtered or unexported fields
}

HostedViewController owns a retained NSViewController returned by the Swift package factory.

func (*HostedViewController) Release

func (c *HostedViewController) Release()

Release releases the retained NSViewController.