Moduli a più passaggi con lo stato del modulo
Divida un lungo modulo di registrazione in più passaggi utilizzando un contatore del passaggio nello stato e convalidi solo i campi del passaggio corrente prima di procedere a quello successivo.
Moduli a più passaggi con lo stato del modulo è una lezione React Native Academy gratuita su CoddyKit. Questa è la lezione 3 di 4. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento React Native Academy, e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso React Native Academy include 4 lezioni in totale.
Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.
What Is a Multi-Step Form?
A multi-step form breaks a long registration or checkout flow into discrete, manageable steps — typically 2 to 5 screens. Each step focuses on a related group of fields, reducing cognitive load and improving completion rates compared to a single long scroll. Common examples include onboarding wizards, address-plus-payment checkout flows, and multi-stage profile setup.
Sharing One Form Instance Across Steps
The key to a multi-step form with react-hook-form is to create one useForm instance for the entire form and pass control and errors down as props to each step component. This keeps all field values and validation state in one place. Values entered on step 1 remain available when the user reaches step 3, and submitting the final step accesses the complete form data.
interface RegisterForm {
name: string;
email: string;
password: string;
phone: string;
city: string;
}
export default function RegisterScreen() {
const [step, setStep] = React.useState(1);
const form = useForm<RegisterForm>({ defaultValues: { name: '', email: '', password: '', phone: '', city: '' } });
return (
<View style={styles.container}>
{step === 1 && <Step1AccountInfo form={form} />}
{step === 2 && <Step2ContactDetails form={form} />}
{step === 3 && <Step3Review form={form} onSubmit={handleFinalSubmit} />}
</View>
);
}Defining Step Component Props
Each step component receives the form instance as a prop. Define a TypeScript type for the prop using UseFormReturn from react-hook-form. This gives the step component access to control, formState.errors, trigger, and watch — all the tools needed to render and validate its own subset of fields.
import type { UseFormReturn } from 'react-hook-form';
interface StepProps {
form: UseFormReturn<RegisterForm>;
onNext?: () => void;
}
export function Step1AccountInfo({ form, onNext }: StepProps) {
const { control, formState: { errors } } = form;
// Render only name, email, and password fields
}Validating Only the Current Step
Before advancing to the next step, validate only the fields on the current step using form.trigger(['fieldA', 'fieldB']). This runs validation on the specified fields and returns a Promise that resolves to true if all are valid. If any fail, the errors appear and the user cannot advance until they are fixed. Fields on later steps are not validated yet.
async function handleNext() {
const step1Fields: (keyof RegisterForm)[] = ['name', 'email', 'password'];
const isValid = await form.trigger(step1Fields);
if (isValid) {
setStep(2);
}
// If invalid, formState.errors is populated for the listed fields
}Progress Indicator UI
Add a visual progress bar or step indicator at the top of the screen so users know how far along they are. Calculate progress as (currentStep / totalSteps) * 100. A simple progress bar using an animated View width gives clear feedback and sets expectations about how much more is required before they can complete the form.
const TOTAL_STEPS = 3;
function ProgressBar({ current }: { current: number }) {
const progress = (current / TOTAL_STEPS) * 100;
return (
<View style={styles.progressContainer}>
<View style={[styles.progressFill, { width: progress + '%' }]} />
</View>
);
}
// Usage:
<ProgressBar current={step} />Navigating Between Steps
Use a step counter in useState to track the current step. 'Next' buttons validate the current step's fields with trigger before incrementing the step. 'Back' buttons decrement the step without re-validating. Always disable the 'Next' button or show a loading spinner while async validation (like username availability checks) is in progress.
const { formState: { isValidating } } = form;
function NavigationButtons() {
return (
<View style={styles.navRow}>
{step > 1 && (
<Button title='Back' onPress={() => setStep((s) => s - 1)} />
)}
{step < TOTAL_STEPS ? (
<Button
title={isValidating ? 'Checking...' : 'Next'}
onPress={handleNext}
disabled={isValidating}
/>
) : (
<Button title='Submit' onPress={form.handleSubmit(onFinalSubmit)} />
)}
</View>
);
}Reviewing Entered Data on the Final Step
The final step is often a review screen where users confirm their entries before submitting. Use form.getValues() to read all field values and display them in a summary list. This gives users one last chance to catch typos before the data is sent to the server, reducing support requests and user errors.
function Step3Review({ form, onSubmit }: StepProps) {
const values = form.getValues();
return (
<ScrollView>
<Text>Review your information:</Text>
<Text>Name: {values.name}</Text>
<Text>Email: {values.email}</Text>
<Text>Phone: {values.phone}</Text>
<Text>City: {values.city}</Text>
<Button title='Confirm and Register' onPress={onSubmit} />
</ScrollView>
);
}Using formState.isSubmitting
formState.isSubmitting is true while handleSubmit's async callback is running. Use it to disable the submit button and show a loading spinner during the API call. This prevents double-submissions when the user taps quickly and gives clear feedback that the form is being processed.
const { formState: { isSubmitting } } = form;
<Button
title={isSubmitting ? 'Submitting...' : 'Confirm and Register'}
onPress={form.handleSubmit(onFinalSubmit)}
disabled={isSubmitting}
/>Persisting Step Data Across Navigation
If users navigate away from the multi-step form and return later, use Zustand or React Navigation's route params to preserve the current step and partially filled form data. Combine this with react-hook-form's reset(savedValues) to restore the form to where the user left off. This dramatically reduces form abandonment on mobile.
// On unmount or navigation away:
useEffect(() => {
return () => {
const currentValues = form.getValues();
useFormDraftStore.getState().saveDraft(currentValues, step);
};
}, []);
// On mount, restore if draft exists:
useEffect(() => {
const draft = useFormDraftStore.getState().draft;
if (draft) {
form.reset(draft.values);
setStep(draft.step);
}
}, []);Keyboard Navigation Between Fields
On mobile, tapping 'Next' on the keyboard should move focus to the next input within a step. Use useRef to hold refs for each TextInput and call ref.current.focus() in the onSubmitEditing callback of each input. Set returnKeyType='next' on intermediate fields and 'done' on the last field of each step.
const emailRef = React.useRef<TextInput>(null);
const passwordRef = React.useRef<TextInput>(null);
<TextInput
placeholder='Full Name'
returnKeyType='next'
onSubmitEditing={() => emailRef.current?.focus()}
/>
<TextInput
ref={emailRef}
placeholder='Email'
returnKeyType='next'
onSubmitEditing={() => passwordRef.current?.focus()}
/>
<TextInput
ref={passwordRef}
placeholder='Password'
returnKeyType='done'
onSubmitEditing={handleNext}
secureTextEntry
/>Handling Back Navigation Safely
When the user presses the hardware back button on Android or swipes back on iOS, handle it to decrement the step counter instead of leaving the screen entirely. Use useFocusEffect with a BackHandler to intercept the hardware back event. If the user is on step 1, allow normal navigation back to the previous screen.
import { BackHandler } from 'react-native';
import { useFocusEffect } from '@react-navigation/native';
useFocusEffect(
React.useCallback(() => {
const handler = BackHandler.addEventListener('hardwareBackPress', () => {
if (step > 1) {
setStep((s) => s - 1);
return true; // prevent default back navigation
}
return false; // allow default (exit screen)
});
return () => handler.remove();
}, [step])
);Quick Check
Test your understanding of React Native Mobile Development concepts from this lesson.
Lesson Recap
In this lesson you learned: one useForm instance shared across all steps keeps form data and validation state unified, trigger with specific field names validates only the current step before advancing, and formState.isSubmitting disables the submit button during the final API call to prevent duplicate submissions. Next up we explore submitting and resetting forms.
Domande Frequenti
La lezione «Moduli a più passaggi con lo stato del modulo» è gratuita?
Sì — il testo completo di «Moduli a più passaggi con lo stato del modulo» è gratuito qui sul web. Per esercitarvi in modo interattivo (un editor di codice integrato e un tutor IA 24/7) e sbloccare il resto del corso React Native Academy, passa a CoddyKit PRO. Il corso React Native Academy include 4 lezioni in totale.
Cosa imparerò in «Moduli a più passaggi con lo stato del modulo»?
Divida un lungo modulo di registrazione in più passaggi utilizzando un contatore del passaggio nello stato e convalidi solo i campi del passaggio corrente prima di procedere a quello successivo. Eserciti React Native Academy con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.
Ho bisogno di esperienza per iniziare React Native Academy?
Non è richiesta alcuna esperienza precedente. React Native Academy su CoddyKit è strutturato per principianti e studenti avanzati, quindi puoi iniziare da qui o dall'inizio e procedere al tuo ritmo. Questa è la lezione 3 di 4.
Quanto tempo richiede la lezione «Moduli a più passaggi con lo stato del modulo»?
La maggior parte delle lezioni CoddyKit richiede circa 5–10 minuti. Ogni lezione è breve e interattiva, quindi fai progressi costanti e riprendi esattamente da dove hai lasciato su web e app.
Posso scrivere ed eseguire codice in questa lezione React Native Academy?
Sì. Ogni lezione React Native Academy include un editor di codice integrato, quindi scrivi ed esegui codice reale direttamente nel tuo browser e ricevi feedback istantaneo dall'IA — nessuna configurazione locale necessaria.
Tutte le lezioni di questo corso
- Configurare react-hook-form con Controller
- Regole di validazione e messaggi di errore
- Moduli a più passaggi con lo stato del modulo
- Invio e reimpostazione dei moduli