Trying to create a function that increments a value, then returns the longPress gesture. Receiving the following

Function declares an opaque return type, but has no return statements in its body from which to infer an underlying type

Reason behind the function would be because I have three buttons that will increase on increments of one.

struct CustomFoodItemView: View {
    @State var foodName = ""
    @State var proteinAmount = 1
    @State var carbAmount = 1
    @State var fatAmount = 1
   
    @State private var timer: Timer?
    @State var isLongPressing = false
    
    var body: some View {
        
        let releaseGesture = DragGesture(minimumDistance: 0) // << detects finger release
            .onEnded { _ in
                self.timer?.invalidate()
            }
        
        func longPressAction ( macroToIncrease: inout Int) -> some Gesture{
            let longPressGesture = LongPressGesture(minimumDuration: 0.2)
                .onEnded { _ in
                    self.timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: { _ in
                        macroToIncrease  = 1
                    })
                    
                }
            return longPressGesture
        }
        
        let proteinCombined = longPressAction(macroToIncrease: &proteinAmount).sequenced(before: releaseGesture)
        
        VStack{
            VStack{
                Text("Food Name")
                TextField("", text: $foodName)
                    .multilineTextAlignment(.center)
                    .border(.white)
                    .padding(.trailing, 10)
                    .frame(width:100, height:10)
            }
            HStack{
                Text(String(proteinAmount)   "g")
                    .frame(width:50, height:50)
                
                Image(systemName: "plus.circle.fill")
                    .resizable()
                        .aspectRatio(contentMode: .fit)
                        .frame(width: 30, height: 30)
                        .foregroundColor(Color("SuccessButtonColor"))
                        .onTapGesture{
                            proteinAmount  = 1
                        }
                        .gesture(proteinCombined)
                        
                       
                Image(systemName: "minus.circle.fill")
                    .resizable()
                        .aspectRatio(contentMode: .fit)
                        .frame(width: 30, height: 30)
                        .foregroundColor(Color("SuccessButtonColor"))
                 
            }
              
            }
        }
        Spacer()
        .frame(maxWidth:.infinity, maxHeight: .infinity)
       
    }
}

CodePudding user response：

Because of the multiple let variables, the view does not know what to display/ return. Put a return before the outer VStack to fix that.

Then remove some curly braces and fix your longPressAction function. This should help: https://www.hackingwithswift.com/books/ios-swiftui/how-to-use-gestures-in-swiftui.

Fixed code:

struct CustomFoodItemView: View {
    @State var foodName = ""
    @State var proteinAmount = 1
    @State var carbAmount = 1
    @State var fatAmount = 1
      
    @State private var timer: Timer?
    @State var isLongPressing = false
       
    var body: some View {
        let releaseGesture = DragGesture(minimumDistance: 0) // << detects finger release
            .onEnded { _ in
                self.timer?.invalidate()
            }
           
        let longPressGesture = LongPressGesture(minimumDuration: 0.2)
            .onEnded { _ in
                self.timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: { _ in
                    proteinAmount  = 1
                })
            }
           
        let proteinCombined = longPressGesture.sequenced(before: releaseGesture)
           
        return VStack {
            VStack {
                Text("Food Name")
                TextField("", text: $foodName)
                    .multilineTextAlignment(.center)
                    .border(.white)
                    .padding(.trailing, 10)
                    .frame(width: 100, height: 10)
            }
            HStack {
                Text(String(proteinAmount)   "g")
                    .frame(width: 50, height: 50)
                   
                Image(systemName: "plus.circle.fill")
                    .resizable()
                    .aspectRatio(contentMode: .fit)
                    .frame(width: 30, height: 30)
                    .foregroundColor(Color("SuccessButtonColor"))
                    .onTapGesture {
                        proteinAmount  = 1
                    }
                    .gesture(proteinCombined)
                   
                Image(systemName: "minus.circle.fill")
                    .resizable()
                    .aspectRatio(contentMode: .fit)
                    .frame(width: 30, height: 30)
                    .foregroundColor(Color("SuccessButtonColor"))
            }
               
            Spacer()
                .frame(maxWidth: .infinity, maxHeight: .infinity)
        }
    }
}