RTIInputSystemClient sessionID Error in SwiftUI: Solutions for Valid Input Operations

var solutions: [Solution] = [
    .simulatorSettings, 
    .focusManagement, 
    .layoutStrategies
]

Problem Statement

When developing SwiftUI authentication screens with text fields, you may encounter the error:

-[RTIInputSystemClient remoteTextInputSessionWithID:performInputOperation:] perform input operation requires a valid sessionID

This error typically occurs when:

1. Tapping authentication buttons after entering text
2. Dismissing the keyboard programmatically
3. Using certain View configurations in iOS 17+
4. Running apps in the Simulator with specific keyboard settings

The core issue relates to the text input system losing its active session context when transitioning between input states, primarily during keyboard dismissal and button interactions.

Recommended Solutions

1. Adjust Simulator Keyboard Settings (For Testing)

When testing in Xcode Simulator:

1. Go to I/O → Keyboard
2. Uncheck Connect Hardware Keyboard
3. Use the on-screen keyboard for input operations

// Alternative focus-based keyboard dismissal
Button("Log In") {
    isInputActive = false  // Cleaner than global resignFirstResponder()
    viewModel.logIn(email: email, password: password)
}

Rationale: The hardware keyboard setting conflicts with SwiftUI's text input session management. Using the software keyboard maintains session integrity during testing.

2. Implement SwiftUI Focus Management

Modify your AuthView with proper focus management:

enum Field: Hashable {
    case email, password
}

struct AuthView: View {
    @FocusState private var focusedField: Field?
    @State private var email = ""
    @State private var password = ""

    var body: some View {
        VStack {
            TextField("Email", text: $email)
                .focused($focusedField, equals: .email)
            
            SecureField("Password", text: $password)
                .focused($focusedField, equals: .password)
            
            Button("Log In") {
                focusedField = nil  // Properly ends text session
                viewModel.logIn(email: email, password: password)
            }
        }
    }
}

Key Changes

1. Replace hideKeyboard() with focus state management
2. Declare explicit focusedField states
3. Set focusedField = nil to dismiss keyboard
4. Remove @FocusState private var isInputActive: Bool

Why it works: SwiftUI's @FocusState properly terminates the input session through its managed state transitions, avoiding the abrupt session termination caused by resignFirstResponder().

3. Optimize Layout Configuration

Use ScrollView with GeometryReader

var body: some View {
    GeometryReader { proxy in
        ScrollView {
            VStack {
                // Text fields and buttons
                
                Spacer().frame(height: 50)  // Keyboard avoidance space
            }
            .frame(minHeight: proxy.size.height)
        }
    }
}

Avoid Lazy Stacks for Input Views

Replace problematic components:

- LazyVStack {
+ VStack {
    TextField(...)
    SecureField(...)
}

iOS 17+ Specifics

Lazy stacks (LazyVStack/LazyHStack) combined with text fields are known to cause input session issues starting in iOS 17. Use regular stacks for input screens.

Layout Rationale: ScrollView ensures proper resizing when keyboards appear/disappear. Non-lazy stacks maintain input context persistence during UI updates.

Best Practices Summary

1. Always manage keyboard through FocusState:

   .focused($fieldState)
   // Instead of
   UIApplication.shared.resignFirstResponder()

2. Test layouts in iOS 17+:

   • Verify stack implementations (VStack vs LazyVStack)
   • Check ScrollView behavior with text fields

3. Maintain session integrity:

   • Avoid abrupt input session termination
   • Ensure 200ms between keyboard dismissal and auth operations

   Button("Submit") {
       focusedField = nil
       DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
           viewModel.authenticate()
       }
   }

These solutions address both the underlying text session management issues and provide resilient layouts for authentication flows in modern SwiftUI applications.