tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        Task.detached {
            await self.heavyCall()
        }
    }

tokizuoh

import UIKit

class ViewModel {
    func heavyCall() {
        var count = 0
        while count < 1_000_000_000 {
            count += 1
        }
        print(Thread.isMainThread)  // false
    }

tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        Task.detached {
            self.heavyCall()
        }
    }

tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        Task.detached {
            await self.heavyCall()
        }
    }

tokizuoh

// ref: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/concurrency/#Defining-and-Calling-Asynchronous-Functions
func generateSlideshow(forGallery gallery: String) async {
    let photos = await listPhotos(inGallery: gallery)
    for photo in photos {
        // ... render a few seconds of video for this photo ...
        await Task.yield()
    }
}

tokizuoh

import Foundation

// ref: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/properties/#Property-Wrappers
@propertyWrapper
struct TwelveOrLess {
    private var number = 0
    
    @MainActor
    var wrappedValue: Int {
        get { return number }

tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        Task.detached {
            let y = Y()
            await y.f()
        }

tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        Task.detached {
            let y = Y()
            y.f()
        }

tokizuoh

import UIKit

class ViewController: UIViewController {
    var callback: () -> Void = { @MainActor in
        print(Thread.isMainThread)  // true or false?
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        

tokizuoh

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        Task.init {
            try await sleep()  // 何秒かかる？
        }
    }