Developing User Registration Screen for Mobile App
Registration screen — user entry point to product. Conversion from "opened app" to "registered" 80% determined by form UX quality and technical details: validation speed, keyboard behavior, server error handling.
Keyboard and focus: details hitting conversion
On iOS UITextField/SwiftUI TextField with wrong keyboardType and textContentType — first issue. Email field without textContentType = .emailAddress won't get Keychain autofill. Password field without textContentType = .newPassword won't trigger system suggestion to generate strong password.
Focus sequence — returnKeyType each field should lead to next or submit:
TextField("Email", text: $email)
.keyboardType(.emailAddress)
.textContentType(.emailAddress)
.submitLabel(.next)
.onSubmit { focusedField = .password }
SecureField("Password", text: $password)
.textContentType(.newPassword)
.submitLabel(.join)
.onSubmit { submitRegistration() }
On Android — imeOptions + nextFocusDown in XML, or ImeAction.Next/ImeAction.Done in Jetpack Compose with explicit focus passing via FocusRequester.
Validation: client and server
Inline validation reduces errors on form submit. Check email with regex, but not too strict — [^@]+@[^@]+\.[^@]+ covers 99% real addresses without false positives. Password — minimum length and character type presence via CharacterSet.
Validate field after losing focus (onBlur), not on every keystroke — no point showing error while user still typing.
Server errors (409 Conflict — email taken, 422 — invalid data) — show under specific field, not generic toast. "This email already registered" + "Sign in" link — right next to email field.
Timeframe
Registration screen with inline validation, correct keyboard behavior, server error handling, and UI test coverage — 3–5 business days per platform.