在SwiftUI中，我发现一个方便的方法是两步方法:

Create a ViewModifier that will embed your view into ZStack and add progress indicator on top. Could be something like this: struct LoadingIndicator: ViewModifier { let width = UIScreen.main.bounds.width * 0.3 let height = UIScreen.main.bounds.width * 0.3 func body(content: Content) -> some View { return ZStack { content .disabled(true) .blur(radius: 2) //gray background VStack{} .frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height) .background(Color.gray.opacity(0.2)) .cornerRadius(20) .edgesIgnoringSafeArea(.all) //progress indicator ProgressView() .frame(width: width, height: height) .background(Color.white) .cornerRadius(20) .opacity(1) .shadow(color: Color.gray.opacity(0.5), radius: 4.0, x: 1.0, y: 2.0) } } Create view extension that will make conditional modifier application available to any view: extension View { /// Applies the given transform if the given condition evaluates to `true`. /// - Parameters: /// - condition: The condition to evaluate. /// - transform: The transform to apply to the source `View`. /// - Returns: Either the original `View` or the modified `View` if the condition is `true`. @ViewBuilder func `if`<Content: View>(_ condition: Bool, transform: (Self) -> Content) -> some View { if condition { transform(self) } else { self } } } Usage is very intuitive. Suppose that myView() returns whatever your view is. You just conditionally apply the modifier using .if view extension from step 2: var body: some View { myView() .if(myViewModel.isLoading){ view in view.modifier(LoadingIndicator()) } }

如果是myViewModel。isLoading为false，没有修饰符将被应用，因此加载指示器将不显示。

当然，您可以使用任何类型的进度指示器—默认的或您自己的自定义的。

除了Mojatba Hosseini的回答，

我做了一些更新，这样就可以把它放在一个快速包中:

活动指标:

import Foundation
import SwiftUI
import UIKit

public struct ActivityIndicator: UIViewRepresentable {

  public typealias UIView = UIActivityIndicatorView
  public var isAnimating: Bool = true
  public var configuration = { (indicator: UIView) in }

 public init(isAnimating: Bool, configuration: ((UIView) -> Void)? = nil) {
    self.isAnimating = isAnimating
    if let configuration = configuration {
        self.configuration = configuration
    }
 }

 public func makeUIView(context: UIViewRepresentableContext<Self>) -> UIView {
    UIView()
 }

 public func updateUIView(_ uiView: UIView, context: 
    UIViewRepresentableContext<Self>) {
     isAnimating ? uiView.startAnimating() : uiView.stopAnimating()
     configuration(uiView)
}}

扩展:

public extension View where Self == ActivityIndicator {
func configure(_ configuration: @escaping (Self.UIView) -> Void) -> Self {
    Self.init(isAnimating: self.isAnimating, configuration: configuration)
 }
}

SwiftUI中的活动指标

import SwiftUI

struct Indicator: View {

    @State var animateTrimPath = false
    @State var rotaeInfinity = false

    var body: some View {

        ZStack {
            Color.black
                .edgesIgnoringSafeArea(.all)
            ZStack {
                Path { path in
                    path.addLines([
                        .init(x: 2, y: 1),
                        .init(x: 1, y: 0),
                        .init(x: 0, y: 1),
                        .init(x: 1, y: 2),
                        .init(x: 3, y: 0),
                        .init(x: 4, y: 1),
                        .init(x: 3, y: 2),
                        .init(x: 2, y: 1)
                    ])
                }
                .trim(from: animateTrimPath ? 1/0.99 : 0, to: animateTrimPath ? 1/0.99 : 1)
                .scale(50, anchor: .topLeading)
                .stroke(Color.yellow, lineWidth: 20)
                .offset(x: 110, y: 350)
                .animation(Animation.easeInOut(duration: 1.5).repeatForever(autoreverses: true))
                .onAppear() {
                    self.animateTrimPath.toggle()
                }
            }
            .rotationEffect(.degrees(rotaeInfinity ? 0 : -360))
            .scaleEffect(0.3, anchor: .center)
            .animation(Animation.easeInOut(duration: 1.5)
            .repeatForever(autoreverses: false))
            .onAppear(){
                self.rotaeInfinity.toggle()
            }
        }
    }
}

struct Indicator_Previews: PreviewProvider {
    static var previews: some View {
        Indicator()
    }
}

// Activity View

struct ActivityIndicator: UIViewRepresentable {

    let style: UIActivityIndicatorView.Style
    @Binding var animate: Bool

    private let spinner: UIActivityIndicatorView = {
        $0.hidesWhenStopped = true
        return $0
    }(UIActivityIndicatorView(style: .medium))

    func makeUIView(context: UIViewRepresentableContext<ActivityIndicator>) -> UIActivityIndicatorView {
        spinner.style = style
        return spinner
    }

    func updateUIView(_ uiView: UIActivityIndicatorView, context: UIViewRepresentableContext<ActivityIndicator>) {
        animate ? uiView.startAnimating() : uiView.stopAnimating()
    }

    func configure(_ indicator: (UIActivityIndicatorView) -> Void) -> some View {
        indicator(spinner)
        return self
    }   
}

// Usage
struct ContentView: View {

    @State var animate = false

    var body: some View {
            ActivityIndicator(style: .large, animate: $animate)
                .configure {
                    $0.color = .red
            }
            .background(Color.blue)
    }
}

我使用SwiftUI实现了经典的UIKit指示器。 点击这里查看活动指示器的运行情况

struct ActivityIndicator: View {
  @State private var currentIndex: Int = 0

  func incrementIndex() {
    currentIndex += 1
    DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(50), execute: {
      self.incrementIndex()
    })
  }

  var body: some View {
    GeometryReader { (geometry: GeometryProxy) in
      ForEach(0..<12) { index in
        Group {
          Rectangle()
            .cornerRadius(geometry.size.width / 5)
            .frame(width: geometry.size.width / 8, height: geometry.size.height / 3)
            .offset(y: geometry.size.width / 2.25)
            .rotationEffect(.degrees(Double(-360 * index / 12)))
            .opacity(self.setOpacity(for: index))
        }.frame(width: geometry.size.width, height: geometry.size.height)
      }
    }
    .aspectRatio(1, contentMode: .fit)
    .onAppear {
      self.incrementIndex()
    }
  }

  func setOpacity(for index: Int) -> Double {
    let opacityOffset = Double((index + currentIndex - 1) % 11 ) / 12 * 0.9
    return 0.1 + opacityOffset
  }
}

struct ActivityIndicator_Previews: PreviewProvider {
  static var previews: some View {
    ActivityIndicator()
      .frame(width: 50, height: 50)
      .foregroundColor(.blue)
  }
}

我已经使用AppKit和SwiftUI修改了Matteo Pacini的macOS答案。这允许你在SwiftUI中使用NSProgressIndicator，同时保留macOS 10.15的功能。

import AppKit
import SwiftUI

struct ActivityIndicator: NSViewRepresentable {
    
    @Binding var isAnimating: Bool
    let style: NSProgressIndicator.Style

    func makeNSView(context: NSViewRepresentableContext<ActivityIndicator>) -> NSProgressIndicator {
        let progressIndicator = NSProgressIndicator()
        progressIndicator.style = self.style
        return progressIndicator
    }

    func updateNSView(_ nsView: NSProgressIndicator, context: NSViewRepresentableContext<ActivityIndicator>) {
        isAnimating ? nsView.startAnimation(nil) : nsView.stopAnimation(nil)
    }
    
}

用法如下:

ActivityIndicator(isAnimating: .constant(true), style: .spinning)