How do you handle forms and user input in React Native?

Question

Accepted Answer

Most apps have **forms** (login, signup, data entry) using **TextInput** and managing input state. React Native handles forms with controlled components, state, and often libraries (Formik, React Hook Form) for complex forms with validation.

## TextInput and controlled inputs

```jsx
import { TextInput } from 'react-native';
import { useState } from 'react';

function LoginForm() {
  const [email, setEmail] = useState('');     // input state
  return (
    <TextInput
      value={email}                            // controlled: value from state
      onChangeText={setEmail}                  // update state on change
      placeholder="Email"
      keyboardType="email-address"             // appropriate keyboard
      autoCapitalize="none"
    />
  );
}
```

A **controlled input** ties the TextInput's value to state (`value` + `onChangeText`) — state is the source of truth for the input. `keyboardType` shows the right keyboard.

## Forms with validation (libraries)

```text
For real forms (multiple fields, validation), libraries reduce boilerplate:
  REACT HOOK FORM → performant, minimal re-renders, popular; handles values + validation
  FORMIK (+ Yup for validation schemas) → another popular form library
→ They manage form state, validation, errors, and submission cleanly.
```

## Best practices

```text
✓ VALIDATE input (required, format, length) → show clear error messages
✓ Use appropriate keyboardType (email, numeric, phone) and input props (secureTextEntry
  for passwords, autoCapitalize, autoComplete)
✓ Handle the keyboard (KeyboardAvoidingView so it doesn't cover inputs)
✓ Provide good UX: loading on submit, disable while submitting, clear feedback
```

## Why it matters

Understanding how to handle forms and user input is essential because **most apps have forms** (login, signup, data entry, search) requiring input handling and validation, so it's must-know practical knowledge.

Forms are a near-universal part of apps.

Understanding **TextInput and controlled inputs** — tying the input's value to state (`value` + `onChangeText`, making state the source of truth) and using appropriate input props (`keyboardType` for the right keyboard, `secureTextEntry` for passwords, autoCapitalize) — is the core mechanism for handling input in React Native.

Understanding that **form libraries** (React Hook Form, Formik with Yup) help with real forms (multiple fields, validation) by managing form state, validation, errors, and submission cleanly is valuable, since hand-managing many fields with useState becomes tedious and error-prone, and these libraries are widely used.

Understanding **best practices** is important: **validating input** (required fields, formats, lengths, with clear error messages — essential for data quality and UX), using appropriate keyboard types and input props (for better input UX), **handling the keyboard** (KeyboardAvoidingView so the keyboard doesn't cover inputs — a common React Native UX issue), and providing good submission UX (loading states, disabling during submission) — these reflect building polished, robust forms.

Since most apps have forms requiring input handling and validation (a near-universal need), and since React Native's TextInput with controlled state, form libraries for complex cases, and the best practices (validation, keyboard handling, good UX) are how you build them well, understanding forms and user input in React Native is essential, frequently-applied knowledge — a core skill needed in nearly every real app that collects input, important for both data correctness (validation) and user experience (keyboard handling, appropriate inputs), and fundamental to building functional React Native applications.