添加或删除视图时，SwiftUI允许您使用combined（with:）方法组合变换以生成新的动画样式

1.示例:

struct ContentView: View {
    @State private var showDetails = false

    var body: some View {
        VStack {
            Button("Press to show details") {
                withAnimation {
                    showDetails.toggle()
                }
            }

            if showDetails {
                Text("Details go here.")
                     .transition(AnyTransition.opacity.combined(with: .slide))
            }
        }

    }
}

考虑到结合动画的复用性,更方便的使用,可以给AnyTransition添加扩展

extension AnyTransition {
    static var moveAndScale: AnyTransition {
        AnyTransition.move(edge: .bottom).combined(with: .scale)
    }
}

struct ContentView: View {
    @State private var showDetails = false

    var body: some View {
        VStack {
            Button("Press to show details") {
                withAnimation {
                    showDetails.toggle()
                }
            }

            if showDetails {
                Text("Details go here.")
                    .transition(.moveAndScale)
            }
        }
    }
}

原文:https://www.hackingwithswift.com/quick-start/swiftui/how-to-combine-transitions