更新由以下所管理的视图的属性'coordinate'时出错：AIRMapMarker（React native）

我一直在网上搜索有关此错误的正确文档，我没有运气，因为我无法确定此错误的原因 .

这是我的整个代码：

First section: 设置状态

export default class Whereto extends Component<{}> {

constructor(props) {
    super(props);

    this.state = {
        latitude: null,
        longitude: null,
        location: null,
        error: null,
        markers:[],

    };
}

Second section 组件确实安装了

componentDidMount() {
        navigator.geolocation.getCurrentPosition(
            (position) => {
                this.setState({
                    latitude: position.coords.latitude,
                    longitude: position.coords.longitude,
                    error: null,
                });

                //geocode api
                var myApiKey = '';

                fetch('https://maps.googleapis.com/maps/api/geocode/json?address=' + position.coords.latitude + ',' + position.coords.longitude + '&key=' + myApiKey)
                    .then((response) => response.json())
                    .then((responseJson) => {
                        //console.log('ADDRESS GEOCODE is BACK!! => ' + JSON.stringify(responseJson));
                        var locationName = responseJson.results[0].address_components.filter(x => x.types.filter(t => t === 'administrative_area_level_2').length > 0)[0].short_name;
                        //console.log(locationName);
                        this.setState({
                            location: locationName,
                        })
                    })

                //nearby api
                var apiPlaceskey = '';
                //https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=-33.8670522,151.1957362&radius=500&type=restaurant&keyword=cruise&key=YOUR_API_KEY

                fetch('https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=' + position.coords.latitude + ',' + position.coords.longitude + '&radius=2000&type=bus_station&key=' + apiPlaceskey)
                    .then((respplaces) => respplaces.json())
                    .then((responseJson2) => {

                        const markers = responseJson2.results.map((result) => ({
                            latlng: {
                                latitude: result.geometry.location.lat,
                                longitude: result.geometry.location.lng,
                            }
                        }));

                        this.setState({ markers });
                    });


            },
            (error) => this.setState({error: error.message}),
            {enableHighAccuracy: true, timeout: 20000, maximumAge: 1000},

        );


    }

Third section ：在我的渲染和视图部分轻触可触摸按钮时保留的功能

fetchDirections = () => {
        //directions api
        var apiDirectionskey = '';
        //const {location} = this.state;
        const {latitude} = this.state;
        const {longitude} = this.state;

        fetch('https://maps.googleapis.com/maps/api/directions/json?origin=' + latitude + ',' + longitude + '&destination=' + goingto + '&mode=transit&transit_mode=bus&key=' + apiDirectionskey)
            .then((resdirections) => resdirections.json())
            .then((responseJson3) => {

                console.log(responseJson3);

            });


        }

    render(){

        return(
            <View style={styles.container}>
                <Mainlogo/>
                <TextInput style={styles.boxInput} underlineColorAndroid='rgba(0,0,0,0)' placeholder="Going To?"
                           underlineColorAndroid='transparent'
                           onChangeText={(dest) => this.setState({goingto : dest})}
                />
                <TouchableOpacity style={styles.button} onPress={this.fetchDirections.bind(this)}>
                    <Text style={styles.textButton}> Go {this.props.type}</Text>
                </TouchableOpacity>

                <MapView style={styles.map}
                         region={{
                             latitude: this.state.latitude,
                             longitude: this.state.longitude,
                             latitudeDelta: 0.02,
                             longitudeDelta: 0.02
                         }}
                >

                </MapView>

                <MapView.Marker
                    coordinate={{
                        latitude: this.state.latitude,
                        longitude: this.state.longitude,
                        latitudeDelta: 0.02,
                        longitudeDelta: 0.02
                    }}
                    image={require('../img/my-pin-512.png')}
                    title={'you are here'}
                />

                {this.state.markers.map(marker => (
                    <MapView.Marker
                        coordinate={marker.latlng}
                        image={require('../img/busstop.png')}

                    />

                ))}





            </View>
        )

    }
}

为了进入这个阶段，从我的主要 Profiles 页面中点击了一个touchableopacity . 我意识到我正在使用componentsndDidMount和一个单独的fetch函数来调用另一个API调用 . 它似乎没有足够的时间来篡改状态以产生空值