React Native Maps - Null Object Reference - react-native-maps

Question

I'm following this tutorial on React Native Maps: https://www.youtube.com/watch?v=MqLC0kOqrwk&t=1s
My code is near identical to the tutors (I didn't use MapView.Markers) but I get this error: Attempt to invoke interface method 'boolean
abi19_0_0.com.facebook.react.bridge.ReadableMap.hasKey(java.lang.String)' on a null object reference
Here is my code:
import React from 'react';
import { View, Text, StyleSheet, Dimensions } from 'react-native';
import MapView from 'react-native-maps';
const { width, height } = Dimensions.get ('window')
const SCREEN_HEIGHT = height
const SCREEN_WIDTH = width
const ASPECT_RATIO = width / height
const LATITUDE_DELTA = 0.0922
const LONGTITUDE_DELTA = LATITUDE_DELTA * ASPECT_RATIO
export default class MapScreen extends React.Component {
constructor (props) {
super (props)
this.state = {
initialPosition: {
latitude: 0,
longitude: 0,
latitudeDelta: 0,
longitudeDelta: 0,
}
}
}
watchID: ?number = null
componentDidMount () {
navigator.geolocation.getCurrentPosition ((position) => {
var lat = parseFloat (position.coords.latitude)
var long = parseFloat (position.coords.longitude)
var initialRegion = {
latitude: lat,
longitude: long,
latitudeDelta: LATITUDE_DELTA,
longitudeDelta: LONGTITUDE_DELTA
}
this.setState ({ initialPosition: initialRegion })
},
(error) => alert (JSON.stringify (error)),
{ enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 })
this.watchID = navigator.geolocation.watchPosition ((position) => {
var lat = parseFloat (position.coords.latitude)
var long = parseFloat (position.coords.longitude)
var lastRegion = {
latitude: lat,
longitude: long,
latitudeDelta: LATITUDE_DELTA,
longitudeDelta: LONGTITUDE_DELTA
}
this.setState ({ initialPosition: lastRegion })
})
}
componentWillUnmount () {
navigator.geolocation.clearWatch (this.watchID)
}
render () {
return (
<MapView
style = { styles.mapContainer }
region = {this.state.initialPosition}
/>
);
}
}

Answer 1

Managed to get this working in a new react-native init project (RN 0.47.1, RNMaps 0.16.0) with the following added to ./android/app/src/main/AndroidManifest.xml:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="WHATEVERYOURAPIKEYIS" />