实现的代码如下：

//
//  LoadingView.swift
//  SwiftBook
//
//  Created by Song on 2024/8/2.
//

import SwiftUI

struct LoadingView: View {
    @State var process = 0.5

    var body: some View {
        VStack(spacing: 20) {
            ZStack {
                Circle()
                    .stroke(.gray.opacity(0.3), lineWidth: 18)
                    .frame(width: 200, height: 200)

                Circle()
                    .trim(from: 0, to: process)
                    .stroke(style: .init(lineWidth: 8, lineCap: .round))
                    .foregroundColor(.green)
                    .frame(width: 200, height: 200)
                    .rotationEffect(.degrees(-90))
            }

            Slider(value: $process, in: 0 ... 1,
                   label: {}, minimumValueLabel: {
                       Text("最小")
                   }, maximumValueLabel: {
                       Text("最大")
                   }).padding(.top, 50)
        }.padding()
    }
}

#Preview {
    LoadingView()
}