Question

我在模式表上有一个退出按钮，可将用户带回登录屏幕。为此，我首先关闭工作表，然后使用asyncAfter（deadline :)设置一个环境变量，使登录页面出现。一切工作正常，但是一旦关闭工作表，从工作表下的视图到登录页面的转换就很麻烦。主要是因为没有一个。顶视图只是消失了，显示了登录视图。我知道我可以创建自定义过渡，但是我不知道在哪里附加它。举例来说，我要淡出工作表下方的视图。（尽管，我愿意接受任何过渡！）

这是控制流量的结构：

struct ConductorView: View {
   @EnvironmentObject var tower: Tower
   let onboardingCompleted = UserDefaults.standard.bool(forKey: "FirstVisit")
    
   var body: some View {
      VStack {
         if tower.currentPage == .onboarding {
            Onboarding1View()
         } else if tower.currentPage == .login {
            LoginView()
         } else if tower.currentPage == .idle {
            LoginView()
         }
      }.onAppear{
         if self.onboardingCompleted {
            self.tower.currentPage = .login
         } else {
            self.tower.currentPage = .onboarding
         }
      }
   }
}

这是工作表上的退出按钮：

Button(action: {
   self.presentationMode.wrappedValue.dismiss()
   DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
      self.tower.currentPage = .login
   }
}) {
   Text("Sign Out")
}

Answer 1

这是您复制的代码的简化演示（我花了更长的时间使其模式可见）。当然，您需要通过更改转场或动画的类型等来对其进行调整。已通过Xcode 12 / iOS 14测试过

class Tower: ObservableObject {
    enum PageType {
        case onboarding, login, idle
    }
    @Published var currentPage: PageType = .onboarding
}

struct ConductorView: View {
   @EnvironmentObject var tower: Tower
   let onboardingCompleted = false

   var body: some View {
      VStack {
         if tower.currentPage == .onboarding {
            Onboarding1View()
         } else if tower.currentPage == .login {
            Text("LoginView")
                .transition(.move(edge: .trailing))    // << here !!
         } else if tower.currentPage == .idle {
            Text("IdleView")
         }
      }
      .animation(.default, value: tower.currentPage)   // << here !!
      .onAppear{
         if self.onboardingCompleted {
            self.tower.currentPage = .login
         } else {
            self.tower.currentPage = .onboarding
         }
      }
   }
}


struct Onboarding1View: View {
   @EnvironmentObject var tower: Tower
    @Environment(\.presentationMode) var presentationMode
    @State private var isPresented = true
    var body: some View {
        Text("Login")
            .sheet(isPresented: $isPresented) {
                Button(action: {
                   self.presentationMode.wrappedValue.dismiss()
                   DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
                      self.tower.currentPage = .login
                   }
                }) {
                   Text("Sign Out")
                }
            }
    }
}

SwiftUI-动画过渡

1 个答案: