ProgressView of SwiftUI

ProgressView.swift

struct ProgressView: View {
    @State private var currentIndex:Int = 0
    @State private var maxIterations:Int = 0
    @State private var publisher = PassthroughSubject<AnimationStatus, Never>()
    
    var body: some View {
        HStack(spacing: 8) {
            ForEach(0..<5) { index in
                RectangleView(index: index, publisher: self.publisher)
            }
        }.onAppear {
            Timer.scheduledTimer(withTimeInterval: 0.5, repeats: true) { (timer) in
                //repeat the animation for three times                                                        
                if self.maxIterations < 3 {
                    if self.currentIndex < self.maxCount {
                        self.publisher.send(AnimationStatus.start(index: self.currentIndex))
                        self.currentIndex += 1
                    } else if self.currentIndex == self.maxCount {
                        self.currentIndex = 0
                        self.maxIterations += 1
                    }
                } else {
                   // sending data via publisher
                    self.publisher.send(.stopAll)
                    self.publisher.send(.start(index: 0))
                }
            }
        }
    }
    
struct RectangleView: View {
    var index: Int
    @State private var animate = false
    var publisher:PassthroughSubject<AnimationStatus, Never>
    var body: some View {
        Rectangle()
            .foregroundColor(Color.green)
            .frame(width: 50, height: 10)
            .opacity(animate ? 1: 0.2)
            .animation(.easeInOut)
            .onReceive(publisher) { (value) in
                switch value {
                case .start(let index):
                    if index == self.index {
                        self.animate = true
                    } else {
                        self.animate = false
                    }
                case .stop(let index):
                    if index == self.index {
                        self.animate = false
                    }
                case .stopAll:
                    self.animate = false
                }
        }
    }
}
    
enum AnimationStatus {
    case start(index:Int)
    case stop(index:Int)
    case stopAll
}