Cannot Convert Value of Type 'Binding<String>' to Expected Argument Type 'Binding<String>'

Cannot convert value of type 'Binding String? ' to expected argument type 'Binding String '

Because all core data fields are optional, you have to wrap it into Binding. And as you're using core data and may face a lot of optionals, you can create an extension:

extension Binding {
     func toUnwrapped<T>(defaultValue: T) -> Binding<T> where Value == Optional<T>  {
        Binding<T>(get: { self.wrappedValue ?? defaultValue }, set: { self.wrappedValue = $0 })
    }
}

Use it like this:

TextField("title", text: $text.name.toUnwrapped(defaultValue: ""))

Cannot convert value of type 'Binding Data Struct? ' to expected argument type 'Binding Data Struct '

In this case I think it should be enough just to unwrap binding, like

if selectedShirt != nil && showDetailShirt{
    
    ShirtDetailView(shirtData: Binding($selectedShirt)!, showDetailShirt: $showDetailShirt,animation: _animation)
}

How to fix Cannot convert value of type 'Binding Device ' to expected argument type 'Device'

The problem here is that on this line:

ForEach($deviceArrays.devices, id: \.id) { deviceArray in

You should use $deviceArray instead, because you are inputting a Binding into the ForEach. Then you can access deviceArray for the regular value.

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Other solution

Use its wrappedValue property.

This converts a type of Binding<T> to T. In your case, Binding<Device> to Device.

ForEach($deviceArrays.devices, id: \.id) { deviceArray in
     HStack {
          ForEach(deviceArray.row, id: \.id) { device in
               AnotherView(device: $currentDevice, size: $size)
                   .onAppear {
                        setCurrentDevice(to: device.wrappedValue)
                    }
        }
    }
}

Swift error, Cannot convert value of type 'Binding String? ' to expected argument type 'Binding String '

The error is originated from this line

Text(message ?? "Message")

because compiler tries to infer type and this line shows that type should be optional, but editor expects not optional, so you got conflict and error. Your message state is not optional so you just need to move default value directly in intializer.

Here is corrected variant:

struct DemoView: View {
    @State var message: String = "Message"
    
    var body: some View {
        VStack {
            ZStack(alignment: .topLeading) {
                TextEditor(text: $message)
                    .frame(minHeight: 30, alignment: .leading)
                    .cornerRadius(6.0)
                    .multilineTextAlignment(.leading)
                Text(message)
                    .padding(.leading, 4)
                    .opacity(message == "" ? 1 : 0)
            }
            .font(.body)
        }
    }
}

Cannot convert value of type 'String' to expected argument type 'Binding String '

It is better to do by separating into different view, like

var body: some View {
        Form {
           Section(header: Text("")) {
               if user.currentAb != nil {
                  SomeNameView(vm: user.currentAb!)
               } else {
                  Text("any holder view here")
               }
            }
        }
}

and separated view

struct SomeNameView: View {
    @ObservedObject var vm: AB

    var body: some View {
       TextField("new name", text: $vm.name)
           .textFieldStyle(RoundedBorderTextFieldStyle())
    }
}

Cannot convert value of type 'Binding Double ' to expected argument type 'Binding Double? '

Here is a solution that allows to disambiguate w/ and w/o value binding.

Tested with Xcode 11.4 / iOS 13.4

struct ChildView: View {
    @Binding var prop: Double?

    init() {
        _prop = .constant(nil)
    }

    init(prop: Binding<Double>) {
        _prop = Binding(prop)
    }

    var body: some View {
        Group {
            if prop != nil {
                Text("Child View: \(prop!)")
            } else {
                Text("Child View")
            }
        }
    }
}

Cannot convert value of type 'Binding _ ' to expected argument type 'Binding Card '

Changing the Binding to ObservedObject compiles and seems to work properly, although I feel like I'm violating single source of truth policy by creating a new ObservedObject.

struct NavView: View {   
    @ObservedObject var item : Card

    ...
}

struct ContentView: View {
private var items: FetchedResults<Card>

var body: some View {
    List {
        ForEach(items) { item in
            NavigationLink {
                NavView(item: item)
            }
        }
    }
}
}

cannot convert value of type 'String' to 'Binding String '

Here is possible approach - to use constant binding for Preview

struct SignInButtons_Previews: PreviewProvider {
    static var previews: some View {
        SignInButtons(backgroundColor: Color.blue,
                      signInUrl: .constant("http://www.apple.com"),
                      showModal: .constant(false))
    }
}

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