Swift Async Block UI

AsyncDemo.swift

//
//  UpdateViewDemo.swift
//  MacOSDemoSwiftUI
//
//  Created by ganzhixiong on 2023/12/14.
//

import SwiftUI

struct UpdateViewDemo: View {
    @StateObject private var myObject = MyObject1(boolValue: true, intValue: 10, stringValue: "Hello", dog: Dog(name: "Fido", age: 3))
    
    func testForInAsync() async {
        print("start for \(Thread.current)")
        for i in 1...1000_000 {
            //            print(i)
        }
        print("end for \(Thread.current)")
    }
    
    var body: some View {
        VStack {
            MillisecondsClockView()
            Button("for 100万 in async") {
                print("myObject.intValue += 1")
                Task.detached {
                    print("start testForInAsync() \(Thread.current)")
                    await testForInAsync()
                    print("end testForInAsync() \(Thread.current)")
                }
            }
            Button("for 100万 in global") {
                print("myObject.intValue += 1")
                // 创建一个后台队列 (Background Queue)
                let queue = DispatchQueue.global(qos: .background)
                queue.async {
                    print("start queue.async \(Thread.current)")
                    for i in 1...1000_000 {
                    }
                }
            }
        }
    }
}

struct MillisecondsClockView: View {
    @State private var currentTime = Date()

    var body: some View {
        VStack {
            Text(getTimeString())
                .font(.largeTitle)
                .padding()

//            Spacer()
        }
        .onAppear {
            startTimer()
        }
    }

    func startTimer() {
        let timer = Timer.scheduledTimer(withTimeInterval: 1/60, repeats: true) { timer in
            currentTime = Date()
//            print(getTimeString())
        }
        RunLoop.current.add(timer, forMode: .common)
    }
    
    func getTimeString() -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = "HH:mm:ss.SSS"
        return formatter.string(from: currentTime)
    }
}

class Dog: ObservableObject {
    @Published var name: String
    @Published var age: Int
    
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
}

class MyObject1: ObservableObject {
    @Published var boolValue: Bool
    @Published var intValue: Int
    @Published var intValue1: Int
    @Published var stringValue: String
    @Published var dog: Dog
    
    init(boolValue: Bool, intValue: Int, stringValue: String, dog: Dog) {
        self.boolValue = boolValue
        self.intValue = intValue
        self.stringValue = stringValue
        self.dog = dog
        self.intValue1 = intValue
    }
}

#Preview {
    UpdateViewDemo()
}