react-native-maps Cannot ref the MapView in Stateless Component

Question

there are a lot of example on how to use react-native-maps in a Class Component but i haven't found those with Stateless Component. I use Stateless Component to access the a global state. I need to move the camera view of the MapView from the initial region after i got the user's location , After searching in internet i somehow ends up with this code that is not working.

import React, { useState, useEffect, useRef } from 'react'
import MapView, { Marker, PROVIDER_GOOGLE } from 'react-native-maps';
...

const Explore = props => {
    const [userCoords, setUserCoords] = useState({
        latitude: 0,
        longitude: 0
    })

    const mapRef = useRef(null);

    onMapReady = () => {
        getUserLocation()
    }

    getUserLocation = async () => {
        Geolocation.getCurrentPosition(
            async (position) => {
                setUserCoords(position.coords)
                mapRef.animateToRegion({
                    latitude: position.coords.latitude,
                    longitude: position.coords.longitude,
                })
            },
            async (error) => {
                // See error code charts below.
                console.log("Geolocation Error" + error.code, error.message);
            },
            { enableHighAccuracy: true, timeout: 15000 }
        );
    }

    return(
    ...
    <MapView
         ref={mapRef}
         onMapReady={() => onMapReady()}
         region={{
             latitude: userCoords.latitude,
             longitude: userCoords.latitude,
             latitudeDelta: 0.0922,
             longitudeDelta: 0.0421,
             showsUserLocation={true}>
             ...
    </MapView>
    )
...
export default Explore

Please help me~ Thank you

Answer 1

而不是使用的mapRef.animateToRegion你需要使用mapRef.current.animateToRegion

Answer 2

there are a lot of example on how to use react-native-maps in a Class Component but i haven't found those with Stateless Component. I use Stateless Component to access the a global state. I need to move the camera view of the MapView from the initial region after i got the user's location , After searching in internet i somehow ends up with this code that is not working.

import React, { useState, useEffect, useRef } from 'react'
import MapView, { Marker, PROVIDER_GOOGLE } from 'react-native-maps';
...

const Explore = props => {
    const [userCoords, setUserCoords] = useState({
        latitude: 0,
        longitude: 0
    })

    const mapRef = useRef(null);

    onMapReady = () => {
        getUserLocation()
    }

    getUserLocation = async () => {
        Geolocation.getCurrentPosition(
            async (position) => {
                setUserCoords(position.coords)
                mapRef.animateToRegion({
                    latitude: position.coords.latitude,
                    longitude: position.coords.longitude,
                })
            },
            async (error) => {
                // See error code charts below.
                console.log("Geolocation Error" + error.code, error.message);
            },
            { enableHighAccuracy: true, timeout: 15000 }
        );
    }

    return(
    ...
    <MapView
         ref={mapRef}
         onMapReady={() => onMapReady()}
         region={{
             latitude: userCoords.latitude,
             longitude: userCoords.latitude,
             latitudeDelta: 0.0922,
             longitudeDelta: 0.0421,
             showsUserLocation={true}>
             ...
    </MapView>
    )
...
export default Explore

Please help me~ Thank you