SwiftUI 如何在选项卡单击时刷新出现

Question

我有 5 个选项卡，每个选项卡都是不同的 View ，并且加载出现。一旦标签被加载 snapper 我怎样才能让它再次重新加载。我是 SwiftUI 的新手，无法完成。所以基本上我有一个带有 5 个选项卡的 TabView View ，其中一个选项卡称为 首页 单击 home 时，它​​会调用另一个名为 TimeLineView 的 View ，该 View 从数据库中获取 OnAppear 数据。由于它是 OnAppear，它第一次工作，但在随后的 taps 中不会再次被调用。我想改变它，以便在每次点击时我都可以调用 OnAppear 或调用 OnAppear 中的函数。任何建议都会很棒

struct TabView : View {
    @State var model: [MainModel]
    @State var selectedTab = "Home"
    var edges = UIApplication.shared.windows.first?.safeAreaInsets
    @Namespace var animation
    @StateObject var modelData = MainViewModel.ModelView()
    @State var IsMainView: MainViewEnum = MainViewEnum.MainView
    @Binding var mainModelValue: MainModelValue

    var body: some View {
        
        VStack(spacing: 0){
            
            GeometryReader{_ in
                
                ZStack{
                    
                    TimeLineView(model: model, isMainView: $IsMainView, newValue: mainModelValue, UserID: 0) // I would like to refresh this on every tap click
                        .opacity(selectedTab == "Home" ? 1 : 0)
                    
                    RankingView()
                        .opacity(selectedTab == "Ranking" ? 1 : 0)
                    
                    TypeCategoryView()
                        .opacity(selectedTab == "Post" ? 1 : 0)
                    
                    MenuView()
                        .opacity(selectedTab == "Menu" ? 1 : 0)
                    
                    InboxView()
                        .opacity(selectedTab == "Inbox" ? 1 : 0)
                    
                }
            }
            .onChange(of: selectedTab) { (_) in
                
                switch(selectedTab){
                
                case "Ranking": if !modelData.isRankingView{modelData.GetRankingView()}
                case "Post": if !modelData.isOrderLoad{modelData.loadOrders()}
                case "Menu": if !modelData.isRewardLoad{modelData.loadReward()}
                case "Inbox": if !modelData.InboxView{modelData.InboxLoad()}
                default: ()
                }
            }
            HStack(spacing: 0){
                
                ForEach(tabs,id: \.self){ tab in
                    
                    TabButton(title: tab, selectedTab: $selectedTab,animation: animation)
                    
                    if tab != tabs.last{
                        Spacer(minLength: 0)
                    }
                }
            }

        }
    }
}



struct TimeLineView: View {
    @State var model: [MainModel]
    @Binding var isMainView: MainViewEnum
    @State var shareSheet = false
    @State var PostIDState = 0
    @State var sharePost: String?
    @State var ProfileID: String?
    @State var FullNameClicked = false
    @State var FullName = ""
    @State var newValue = MainModelValue()
    @State var UserID: Int
    
    var body: some View {
        ZStack
        {
            Color(UIColor.white)
                .ignoresSafeArea()
            
            ScrollView(showsIndicators: false) {
                LazyVStack {
                  
                    if isMainView == MainViewEnum.MainView {
                    TestView(model: $model)
                    }
                    let result = model.sorted {
                        $0.id! > $1.id!
                    }
                    
                    ForEach(result) { value in
                       
                        Spacer()
                        VStack(alignment: .leading) {
                        HStack {
     
                           Text("\(value.initials!)")
                            .fontWeight(.bold)
                                .frame(width: 35, height: 35, alignment: .center)
                            .foregroundColor(Color(SystemColorPicked(picked: value.color)))
                                .padding()
                                .overlay(
                                    Circle()
                                    .stroke(Color.black, lineWidth: 1)
                                    .padding(6)
                                )
    
                            VStack(alignment: .leading, spacing: 1) {
                                HStack {
                                    Text("\(value.fullname)")
                                        .font(.system(size: 15))
                                        .bold()
                                        .onTapGesture {
                                            FullNameClicked.toggle()
                                            FullName = value.fullname
                                            ProfileID = String(value.profile_id)
                                        }
                                    Spacer()
                                   
                                }.padding(.leading, 13)
                        
                            }
                        }
                        
                            VStack(alignment: .leading, spacing: 1) {
                                HStack {
                                    
                                   if value.post.count >= 100 {

                              
                                    PostShowView(text: value.post)

                                   } else {
                                        Text("\(value.post)")
                                       .fixedSize(horizontal: false, vertical: true)
                                       .font(.system(size: 15))
                                    }
                   
                                }.padding(.leading, 90)

                                    Spacer()
                                    
                                }.padding(.leading, 90)
                                
                                VStack {
                                    Spacer()
                                    Divider()
                                }.padding(.leading, 90)
                                
                         }
          
                    }
                }.padding(25.0)
            }.padding(.top, 2.0)
            
        }
        .listRowInsets(.none)
        .onAppear(){
        // I would like this to execute every time this View is called
            MainViewModel().MainViewRequests(46, model: newValue) { data in
                self.model = data!
                
            }
            
        }
    }
}

Answer 1

试试 DeferView (取自我在 https://stackoverflow.com/a/61242931/12299030 中的回答)，例如

DeferView  {
   TimeLineView(model: model, 
                isMainView: $IsMainView, 
                newValue: mainModelValue, 
                UserID: 0)
}.opacity(selectedTab == "Home" ? 1 : 0)