How would I code this Tab Bar in Flutter?

Question

I have some experience with SwiftUI and I wrote this code some time ago. I am currently learning how to use Flutter to build UI. How would I go about coding this? It's a floating Tab Bar that can open and close by swiping it.

This is basically an rounded rectangle HStack with 5 buttons inside of it that can animate into a single button if it's swiped or long pressed. I have just started with Flutter a couple of days ago and I'm still struggling a bit to convert my SwiftUI logic to Flutter. Any ideas?

struct TabBar: View {
    
@Binding var selected : Int
@State var expand = true
    
    var drag: some Gesture {
        DragGesture()
            .onChanged {_ in self.expand = false}
        }

var body: some View {
        
    HStack {
        Spacer(minLength:0)
        
        HStack{
            
            if !self.expand{
                
                Button(action: {
                    self.expand.toggle()
                }) {
                    Image("appleLogo")
                        .resizable()
                        .aspectRatio(contentMode: .fill)
                        .frame(width: 15, height: 15, alignment: .center)
                        .foregroundColor(.black)
                        .scaleEffect(2)
                        .padding()
                }
                
            }
                
            else{
                Button(action: {
                    self.selected = 0
                            }) {
                                ZStack {
                                    
                                    Circle()
                                    .frame(width: 40, height: 40)
                                    .opacity(0)
                                    
                                    Image(systemName: "house")
                                        .foregroundColor(self.selected == 0 ? .black : Color("darkGray"))
                                        .padding(.horizontal)
                                        .scaleEffect(1.5)
                                }
                            }
                            
                            Spacer(minLength:15)
                            
                            Button(action: {
                                self.selected = 1
                            }) {
                                ZStack {
                                    
                                    Circle()
                                    .frame(width: 40, height: 40)
                                    .opacity(0)
                                    
                                    Image(systemName: "bubble.left")
                                        .foregroundColor(self.selected == 1 ? .black : Color("darkGray"))
                                        .padding(.horizontal)
                                        .scaleEffect(1.5)
                                }
                            }
                            
                            Spacer(minLength:15)

                            Button(action: {
                                self.selected = 2
                            }) {
                                ZStack {
                                    
                                    Circle()
                                    .frame(width: 40, height: 40)
                                    .opacity(0)
                                    
                                    Image(systemName: "plus.app")
                                        .foregroundColor(self.selected == 2 ? .black : Color("darkGray"))
                                        .padding(.horizontal)
                                        .scaleEffect(1.5)
                                }
                            }
                            
                            Spacer(minLength:15)
                            
                            Button(action: {
                                self.selected = 3
                            }) {
                                ZStack {
                                    
                                    Circle()
                                    .frame(width: 40, height: 40)
                                    .opacity(0)
                                    
                                    Image(systemName: "cart")
                                        .foregroundColor(self.selected == 3 ? .black : Color("darkGray"))
                                        .padding(.horizontal)
                                        .scaleEffect(1.5)
                                }
                            }
                            
                            Spacer(minLength:15)

                            Button(action: {
                                self.selected = 4
                            }) {
                                ZStack {
                                    
                                    Circle()
                                        .frame(width: 40, height: 40)
                                        .opacity(0)
                                    
                                    Image(systemName: "person")
                                        .foregroundColor(self.selected == 4 ? .black : Color("darkGray"))
                                        .padding(.horizontal)
                                        .scaleEffect(1.5)
                                }
                            }
                            
                        }
                    }
        .padding(.vertical,self.expand ? 8 : 6)
        .padding(.horizontal,self.expand ? 20 : 6)
        .background(VisualEffectView())
        .background(Color("TabBarGray").opacity(0.3))
        .opacity(self.expand ? 1.0 : 0.3)
        .clipShape(Capsule())
        .padding(30)
        .onLongPressGesture {
            self.expand.toggle()}
        .gesture(drag)
        .animation(.interactiveSpring(response:0.6, dampingFraction:0.6, blendDuration:0.6))
        .frame(maxWidth: UIScreen.main.bounds.width,
               maxHeight: UIScreen.main.bounds.height, alignment: .center)
                }
            }
        }

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Answer 1

I am also new to Flutter but generally speaking I would create a stateful widget to store the state of the button bar. Then you create the button bar as a stateless widget (using Container(child:Row(children...)

In the stateful widget you wrap the call of the stateless widget with whatever enables swiping (haven't used this so far). In there you will have something like setState(() {expanded = !expanded}) and possibly you call the stateless widget with something like

Container(
  child: (expanded ? ShowBar() : Container()),
  )

where you either show your stateless widget class ShowBar or an empty Container