fix

dimensionhub/Views/Index/IndexMainView.swift

@@ -29,6 +29,9 @@ struct IndexMainView: View {
     @State private var footerRefreshing: Bool = false
     @State private var noMore: Bool = false
     
+    @State private var scrollOffset: CGFloat = 0
+    @State private var showFloatGroupLabel: Bool = false
+    
     var body: some View {
         VStack(alignment: .center) {
             
@@ -61,8 +64,16 @@ struct IndexMainView: View {
             .background(Color(hex: "#F2F2F2"), ignoresSafeAreaEdges: .top)
             
             ScrollView(.vertical, showsIndicators: false) {
-                Rectangle()
-                    .frame(width: 0, height: 38)
+                ScrollViewOffsetReader(offset: $scrollOffset)
+                
+                MixGroupLabelView(fixedDramaGroup: indexModel.fixedDramaGroup) {
+                    if let groupId = indexModel.fixedDramaGroup?.group_id {
+                        selectGroupId = groupId
+                        indexModel.selectedDate = groupId
+                        showDateNavPopover = true
+                    }
+                }
+                .opacity(!showFloatGroupLabel ? 1 : 0)
                 
                 // 基于日期的更新列表
                 LazyVStack(alignment: .center, spacing: 10) {
@@ -87,6 +98,9 @@ struct IndexMainView: View {
             .frame(width: 370)
             .coordinateSpace(name: "indexScrollView")
             .scrollPosition(id: $scrollID)
+            .onChange(of: scrollOffset) {
+                self.showFloatGroupLabel = scrollOffset < 0
+            }
             .refreshable {
                 guard !self.showDateNavPopover && !self.headerRefreshing else {
                     return
@@ -107,37 +121,15 @@ struct IndexMainView: View {
                 }
             }
             .overlay(alignment: .topTrailing) {
-                HStack(alignment: .center) {
-                    Button(action: {
-                        appNavigation.append(dest: .search)
-                    }) {
-                        Image(systemName: "magnifyingglass")
-                            .font(.system(size: 20))
-                    }
-                    
-                    Spacer()
-                    
-                    if let fixedDramaGroup = indexModel.fixedDramaGroup {
-                        Text(fixedDramaGroup.group_name)
-                            .font(.system(size: 18))
-                            .fontWeight(.regular)
-                            .onTapGesture {
-                                selectGroupId = fixedDramaGroup.group_id
-                                indexModel.selectedDate = fixedDramaGroup.group_id
+                MixGroupLabelView(fixedDramaGroup: indexModel.fixedDramaGroup) {
+                    if let groupId = indexModel.fixedDramaGroup?.group_id {
+                        selectGroupId = groupId
+                        indexModel.selectedDate = groupId
                         showDateNavPopover = true
                     }
+                    
                 }
-                }
-                .padding([.top, .bottom], 8)
-                .background(.white)
-                .background(
-                    GeometryReader { geometry in
-                        Color.clear
-                            .onAppear {
-                                print("hstack height is: \(geometry.size.height)")
-                            }
-                    }
-                )
+                .opacity(showFloatGroupLabel ? 1 : 0)
             }
         }
         .ignoresSafeArea(edges: .bottom)
@@ -156,10 +148,69 @@ struct IndexMainView: View {
         }
     }
     
+    struct ScrollViewOffsetReader: View {
+        @Binding var offset: CGFloat
+        
+        var body: some View {
+            GeometryReader { geometry in
+                Color.clear
+                    .preference(
+                        key: ScrollOffsetPreferenceKey.self,
+                        value: geometry.frame(in: .named("indexScrollView")).origin.y
+                    )
+            }
+            .frame(height: 0)
+            .onPreferenceChange(ScrollOffsetPreferenceKey.self) { value in
+                DispatchQueue.main.async {
+                    self.offset = value
+                }
+            }
+        }
+    }
+
+    struct ScrollOffsetPreferenceKey: PreferenceKey {
+        static var defaultValue: CGFloat = 0
+        
+        static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
+            value = nextValue()
+        }
+    }
+    
 }
 
 extension IndexMainView {
     
+    struct MixGroupLabelView: View {
+        @EnvironmentObject var appNav: AppNavigation
+        
+        let fixedDramaGroup: IndexModel.UpdateDramaGroup?
+        let onTap: () -> Void
+        
+        var body: some View {
+            HStack(alignment: .center) {
+                Button(action: {
+                    appNav.append(dest: .search)
+                }) {
+                    Image(systemName: "magnifyingglass")
+                        .font(.system(size: 20))
+                }
+                
+                Spacer()
+                
+                if let fixedDramaGroup {
+                    Text(fixedDramaGroup.group_name)
+                        .font(.system(size: 18))
+                        .fontWeight(.regular)
+                        .onTapGesture {
+                            onTap()
+                        }
+                }
+            }
+            .padding([.top, .bottom], 8)
+            .background(.white)
+        }
+    }
+    
     // 显示分组信息
     struct DramaGroupLabelView: View {
         let group_name: String

dimensionhub/Views/Index/IndexModel.swift

@@ -65,6 +65,9 @@ final class IndexModel {
     // 转换后的数据, 方便在一次循环中展示数据
     var dramaGroupElements: [GroupElement] = []
     
+    // 判断GroupLabel的显示方式
+    var showFloatGroupLabel: Bool = false
+    
     var follow_num: String = "0"
     
     // 用来显示固定栏目的group_name