Oct. 2017 J'ai trouvé cela ridiculement confus, alors voici ma solution en partant du haut vers le bas :
Je recommande de commencer un nouveau projet et de coller littéralement tout cela et de l'étudier ensuite. J'ai beaucoup commenté le code, donc si vous êtes bloqué sur un point spécifique, le contexte peut peut-être vous aider à vous remettre sur les rails.
Ce post montre comment :
- configurer complètement React Native pour exécuter react-navigation
- Intégrer correctement avec Redux
- Manipuler le bouton arrière d'Android
- Navigateurs de la pile Nest
- Naviguer d'un navigateur enfant à un navigateur parent
- Réinitialiser la pile de navigation
- Réinitialisation de la pile de navigation lors de la navigation d'un enfant à un parent (imbriqué)
index.js
import { AppRegistry } from 'react-native'
import App from './src/App'
AppRegistry.registerComponent('yourappname', () => App)
src/App.js (c'est le fichier le plus important car il rassemble tous les morceaux)
import React, { Component } from 'react'
// this will be used to make your Android hardware Back Button work
import { Platform, BackHandler } from 'react-native'
import { Provider, connect } from 'react-redux'
import { addNavigationHelpers } from 'react-navigation'
// this is your root-most navigation stack that can nest
// as many stacks as you want inside it
import { NavigationStack } from './navigation/nav_reducer'
// this is a plain ol' store
// same as const store = createStore(combinedReducers)
import store from './store'
// this creates a component, and uses magic to bring the navigation stack
// into all your components, and connects it to Redux
// don't mess with this or you won't get
// this.props.navigation.navigate('somewhere') everywhere you want it
// pro tip: that's what addNavigationHelpers() does
// the second half of the critical logic is coming up next in the nav_reducers.js file
class App extends Component {
// when the app is mounted, fire up an event listener for Back Events
// if the event listener returns false, Back will not occur (note that)
// after some testing, this seems to be the best way to make
// back always work and also never close the app
componentWillMount() {
if (Platform.OS !== 'android') return
BackHandler.addEventListener('hardwareBackPress', () => {
const { dispatch } = this.props
dispatch({ type: 'Navigation/BACK' })
return true
})
}
// when the app is closed, remove the event listener
componentWillUnmount() {
if (Platform.OS === 'android') BackHandler.removeEventListener('hardwareBackPress')
}
render() {
// slap the navigation helpers on (critical step)
const { dispatch, nav } = this.props
const navigation = addNavigationHelpers({
dispatch,
state: nav
})
return <NavigationStack navigation={navigation} />
}
}
// nothing crazy here, just mapping Redux state to props for <App />
// then we create your root-level component ready to get all decorated up
const mapStateToProps = ({ nav }) => ({ nav })
const RootNavigationStack = connect(mapStateToProps)(App)
const Root = () => (
<Provider store={store}>
<RootNavigationStack />
</Provider>
)
export default Root
src/navigation/nav_reducer.js
// NavigationActions is super critical
import { NavigationActions, StackNavigator } from 'react-navigation'
// these are literally whatever you want, standard components
// but, they are sitting in the root of the stack
import Splash from '../components/Auth/Splash'
import SignUp from '../components/Auth/SignupForm'
import SignIn from '../components/Auth/LoginForm'
import ForgottenPassword from '../components/Auth/ForgottenPassword'
// this is an example of a nested view, you might see after logging in
import Dashboard from '../components/Dashboard' // index.js file
const WeLoggedIn = StackNavigator({
LandingPad: { // if you don't specify an initial route,
screen: Dashboard // the first-declared one loads first
}
}, {
headerMode: 'none'
initialRouteName: LandingPad // if you had 5 components in this stack,
}) // this one would load when you do
// this.props.navigation.navigate('WeLoggedIn')
// notice we are exporting this one. this turns into <RootNavigationStack />
// in your src/App.js file.
export const NavigationStack = StackNavigator({
Splash: {
screen: Splash
},
Signup: {
screen: SignUp
},
Login: {
screen: SignIn
},
ForgottenPassword: {
screen: ForgottenPassword
},
WeLoggedIn: {
screen: WeLoggedIn // Notice how the screen is a StackNavigator
} // now you understand how it works!
}, {
headerMode: 'none'
})
// this is super critical for everything playing nice with Redux
// did you read the React-Navigation docs and recall when it said
// most people don't hook it up correctly? well, yours is now correct.
// this is translating your state properly into Redux on initialization
const INITIAL_STATE = NavigationStack.router.getStateForAction(NavigationActions.init())
// this is pretty much a standard reducer, but it looks fancy
// all it cares about is "did the navigation stack change?"
// if yes => update the stack
// if no => pass current stack through
export default (state = INITIAL_STATE, action) => {
const nextState = NavigationStack.router.getStateForAction(action, state)
return nextState || state
}
src/store/index.js
// remember when I said this is just a standard store
// this one is a little more advanced to show you
import { createStore, compose, applyMiddleware } from 'redux'
import thunk from 'redux-thunk'
import { persistStore, autoRehydrate } from 'redux-persist'
import { AsyncStorage } from 'react-native'
// this pulls in your combinedReducers
// nav_reducer is one of them
import reducers from '../reducers'
const store = createStore(
reducers,
{},
compose(
applyMiddleware(thunk),
autoRehydrate()
)
)
persistStore(store, { storage: AsyncStorage, whitelist: [] })
// this exports it for App.js
export default store
src/reducers.js
// here is my reducers file. I don't want any confusion
import { combineReducers } from 'redux'
// this is a standard reducer, same as you've been using since kindergarten
// with action types like LOGIN_SUCCESS, LOGIN_FAIL
import loginReducer from './components/Auth/login_reducer'
import navReducer from './navigation/nav_reducer'
export default combineReducers({
auth: loginReducer,
nav: navReducer
})
src/composants/Auth/SignUpForm.js
Je vais vous montrer un exemple ici. Ce n'est pas de moi, je l'ai juste tapé pour vous dans cet éditeur de StackOverflow bancal. Merci de me donner des pouces en l'air si vous l'appréciez :)
import React, { Component } from 'react'
import { View, Text, TouchableOpacity } from 'react-native
// notice how this.props.navigation just works, no mapStateToProps
// some wizards made this, not me
class SignUp extends Component {
render() {
return (
<View>
<Text>Signup</Text>
<TouchableOpacity onPress={() => this.props.navigation.navigate('Login')}>
<Text>Go to Login View</Text>
</TouchableOpacity>
</View>
)
}
}
export default SignUp
src/composants/Auth/LoginForm.js
Je vous montrerai aussi un style débile, avec un bouton arrière super cool.
import React from 'react'
import { View, Text, TouchableOpacity } from 'react-native
// notice how we pass navigation in
const SignIn = ({ navigation }) => {
return (
<View>
<Text>Log in</Text>
<TouchableOpacity onPress={() => navigation.goBack(null)}>
<Text>Go back to Sign up View</Text>
</TouchableOpacity>
</View>
)
}
export default SignIn
src/composants/Auth/Splash.js
Voici un écran d'accueil avec lequel vous pouvez jouer. Je l'utilise comme un composant d'ordre supérieur :
import React, { Component } from 'react'
import { StyleSheet, View, Image, Text } from 'react-native'
// https://github.com/oblador/react-native-animatable
// this is a library you REALLY should be using
import * as Animatable from 'react-native-animatable'
import { connect } from 'react-redux'
import { initializeApp } from './login_actions'
class Splash extends Component {
constructor(props) {
super(props)
this.state = {}
}
componentWillMount() {
setTimeout(() => this.props.initializeApp(), 2000)
}
componentWillReceiveProps(nextProps) {
// if (!nextProps.authenticated) this.props.navigation.navigate('Login')
if (nextProps.authenticated) this.props.navigation.navigate('WeLoggedIn')
}
render() {
const { container, image, text } = styles
return (
<View style={container}>
<Image
style={image}
source={require('./logo.png')}
/>
<Animatable.Text
style={text}
duration={1500}
animation="rubberBand"
easing="linear"
iterationCount="infinite"
>
Loading...
</Animatable.Text>
<Text>{(this.props.authenticated) ? 'LOGGED IN' : 'NOT LOGGED IN'}</Text>
</View>
)
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F0F0F0'
},
image: {
height: 110,
resizeMode: 'contain'
},
text: {
marginTop: 50,
fontSize: 15,
color: '#1A1A1A'
}
})
// my LOGIN_SUCCESS action creator flips state.auth.isAuthenticated to true
// so this splash screen just watches it
const mapStateToProps = ({ auth }) => {
return {
authenticated: auth.isAuthenticated
}
}
export default connect(mapStateToProps, { initializeApp })(Splash)
src/composants/Auth/login_actions.js
Je vais juste vous montrer initializeApp() pour que vous ayez quelques idées :
import {
INITIALIZE_APP,
CHECK_REMEMBER_ME,
TOGGLE_REMEMBER_ME,
LOGIN_INITIALIZE,
LOGIN_SUCCESS,
LOGIN_FAIL,
LOGOUT
} from './login_types'
//INITIALIZE APP
// this isn't done, no try/catch and LOGIN_FAIL isn't hooked up
// but you get the idea
// if a valid JWT is detected, they will be navigated to WeLoggedIn
export const initializeApp = () => {
return async (dispatch) => {
dispatch({ type: INITIALIZE_APP })
const user = await AsyncStorage.getItem('token')
.catch((error) => dispatch({ type: LOGIN_FAIL, payload: error }))
if (!user) return dispatch({ type: LOGIN_FAIL, payload: 'No Token' })
return dispatch({
type: LOGIN_SUCCESS,
payload: user
})
// navigation.navigate('WeLoggedIn')
// pass navigation into this function if you want
}
}
Dans d'autres cas d'utilisation, vous pouvez préférer le composant d'ordre supérieur. Ils fonctionnent exactement de la même manière que React pour le web. Les tutoriels de Stephen Grider sur Udemy sont les meilleurs, point final.
src/HOC/require_auth.js
import React, { Component } from 'react'
import { connect } from 'react-redux'
export default function (ComposedComponent) {
class Authentication extends Component {
componentWillMount() {
if (!this.props.authenticated) this.props.navigation.navigate('Login')
}
componentWillUpdate(nextProps) {
if (!nextProps.authenticated) this.props.navigation.navigate('Login')
}
render() {
return (
<ComposedComponent {...this.props} />
)
}
}
const mapStateToProps = ({ auth }) => {
return {
authenticated: auth.isAuthenticated
}
}
return connect(mapStateToProps)(Authentication)
}
Tu l'utilises comme ça :
import requireAuth from '../HOC/require_auth'
class RestrictedArea extends Component {
// ... normal view component
}
//mappage de l'état aux accessoires
export default connect(mapStateToProps, actions)(requireAuth(RestrictedArea))
Voilà, c'est tout ce que j'aimerais que quelqu'un me dise et me montre.
TLDR Le site App.js
y nav_reducer.js
Les fichiers sont absolument les plus importants à obtenir. Le reste est bien connu. Mes exemples devraient faire de vous une machine de productivité sauvage.
[Voici le créateur de mon action de déconnexion. Vous le trouverez très utile si vous souhaitez effacer votre pile de navigation afin que l'utilisateur ne puisse pas appuyer sur le bouton Retour du matériel Android et revenir à un écran qui nécessite une authentification :
//LOGOUT
export const onLogout = (navigation) => {
return async (dispatch) => {
try {
await AsyncStorage.removeItem('token')
navigation.dispatch({
type: 'Navigation/RESET',
index: 0,
actions: [{ type: 'Navigate', routeName: 'Login' }]
})
return dispatch({ type: LOGOUT })
} catch (errors) {
// pass the user through with no error
// this restores INITIAL_STATE (see login_reducer.js)
return dispatch({ type: LOGOUT })
}
}
}
// login_reducer.js
case LOGOUT: {
return {
...INITIAL_STATE,
isAuthenticated: false,
}
}
[Comment naviguer d'un navigateur de pile enfant à un navigateur de pile parent ?
Si vous souhaitez naviguer à partir de l'un de vos navigateurs de pile enfant et réinitialiser la pile, procédez comme suit :
- Soyez à l'intérieur d'un composant ajoutant du code, où vous avez
this.props.navigation
disponible sur
- Créez un composant comme
<Something />
- Passez la navigation dedans, comme ceci :
<Something navigation={this.props.navigation} />
- Allez dans le code de ce composant
- Remarquez comment vous avez
this.props.navigation
disponible dans ce composant enfant
- Maintenant que vous avez terminé, il suffit d'appeler
this.props.navigation.navigate('OtherStackScreen')
et vous devriez voir React Native s'y rendre comme par magie sans problème.
Mais, je veux Réinitialiser l'ensemble de la pile tout en naviguant vers une pile parent.
- Appelez un créateur d'action ou quelque chose comme ça (en partant de l'étape 6) :
this.props.handleSubmit(data, this.props.navigation)
- Allez dans le créateur d'action et observez ce code qui pourrait s'y trouver :
créateurs d'actions.js
// we need this to properly go from child to parent navigator while resetting
// if you do the normal reset method from a child navigator:
this.props.navigation.dispatch({
type: 'Navigation/RESET',
index: 0,
actions: [{ type: 'Navigate', routeName: 'SomeRootScreen' }]
})
// you will see an error about big red error message and
// screen must be in your current stack
// don't worry, I got your back. do this
// (remember, this is in the context of an action creator):
import { NavigationActions } from 'react-navigation'
// notice how we passed in this.props.navigation from the component,
// so we can just call it like Dan Abramov mixed with Gandolf
export const handleSubmit = (token, navigation) => async (dispatch) => {
try {
// lets do some operation with the token
await AsyncStorage.setItem('token@E1', token)
// let's dispatch some action that doesn't itself cause navigation
// if you get into trouble, investigate shouldComponentUpdate()
// and make it return false if it detects this action at this moment
dispatch({ type: SOMETHING_COMPLETE })
// heres where it gets 100% crazy and exhilarating
return navigation.dispatch(NavigationActions.reset({
// this says put it on index 0, aka top of stack
index: 0,
// this key: null is 9001% critical, this is what
// actually wipes the stack
key: null,
// this navigates you to some screen that is in the Root Navigation Stack
actions: [NavigationActions.navigate({ routeName: 'SomeRootScreen' })]
}))
} catch (error) {
dispatch({ type: SOMETHING_COMPLETE })
// User should login manually if token fails to save
return navigation.dispatch(NavigationActions.reset({
index: 0,
key: null,
actions: [NavigationActions.navigate({ routeName: 'Login' })]
}))
}
}
J'utilise ce code dans une application React Native d'entreprise, et il fonctionne parfaitement.
react-navigation
est comme la programmation fonctionnelle. Elle est conçue pour être manipulée en petits fragments de "pure navigation" qui se composent bien ensemble. Si vous employez la stratégie décrite ci-dessus, vous vous retrouverez à créer une logique de navigation réutilisable que vous pourrez simplement coller selon vos besoins.