Reactネイティブfetch（）が動作しない

Question

Google APIからデータを取得する反復ネイティブアプリを作成しようとしていますが、未処理のJS例外：未定義がオブジェクトではありません（responseData [0] .destination_addresses '））。

'use strict'; 

var React = require('react-native'); 
var { 
    AppRegistry, 
    StyleSheet, 
    Text, 
    View, 
    TouchableHighlight, 
} = React; 

var INITIAL_DATA = [ 
    {city: 'CityName', duration: "0 hours"}, 
]; 

var REQUEST_URL = 'https://maps.googleapis.com/maps/api/distancematrix/json?mode=driving&language=en&origins=Austin&destinations=San+Francisco&key=PRIVACY'; 

var AwesomeProject = React.createClass({ 
    getInitialState: function() { 
    return { 
     data: INITIAL_DATA[0], 
    }; 
    }, 

    componentDidMount: function() { 
    this.fetchData(); 
    }, 

    fetchData: function() { 
    fetch(REQUEST_URL) 
     .then((response) => response.json()) 
     .then((responseData) => { 

     this.setState({ 
      data: { city: responseData[0].destination_addresses[0].rendered, duration: responseData[0].rows[0].elements[0].duration.text.rendered }, 
     }); 
     }) 
     .done(); 
    }, 
    render: function() { 
    return (
     <View style={styles.container}> 
     <View style={styles.textContainer}> 
      <Text style={styles.city}> 
      {this.state.data.city} 
      </Text> 
      <Text style={styles.text}> 
      {this.state.data.duration} 
      </Text> 
     </View> 

     </View> 
    ); 
    } 
}); 

var Dimensions = require('Dimensions'); 
var windowSize = Dimensions.get('window'); 

var styles = StyleSheet.create({ 
    container: { 
    flex: 1, 
    justifyContent: 'center', 
    alignItems: 'center', 
    backgroundColor: '#FFFFFF', 
    }, 
    textContainer: { 
    flex: 1, 
    justifyContent: 'center', 
    alignItems: 'center', 
    }, 
    city: { 
    fontSize: 30, 
    textAlign: 'center', 
    margin: 10, 
    }, 
    text: { 
    fontSize: 18, 
    paddingLeft: 20, 
    paddingRight: 20, 
    textAlign: 'center', 
    color: '#333333', 
    marginBottom: 5, 
    }, 
    buttonContainer: { 
    bottom: 0, 
    flex: .1, 
    width: windowSize.width, 
    backgroundColor: '#eee', 
    }, 
    button: { 
    flex: 1, 
    alignItems: 'center', 
    justifyContent: 'center', 
    }, 
    buttonText: { 
    fontSize: 30, 
    color: '#666666', 
    }, 
}); 


AppRegistry.registerComponent('AwesomeProject',() => AwesomeProject); 

そして、この私が解析していますJSONレスポンス：

{ 
    "destination_addresses" : [ "San Francisco, CA, USA" ], 
    "origin_addresses" : [ "Austin, TX, USA" ], 
    "rows" : [ 
     { 
     "elements" : [ 
      { 
       "distance" : { 
        "text" : "2,830 km", 
        "value" : 2830409 
       }, 
       "duration" : { 
        "text" : "1 day 1 hour", 
        "value" : 90952 
       }, 
       "status" : "OK" 
      } 
     ] 
     } 
    ], 
    "status" : "OK" 
} 

Answer 1

私はあなたがステータスコードをチェックする必要があると考えている。ここ

はコードです。

fetch(REQUEST_URL) 
    .then((response) => response.json()) 
    .then((responseData) => { 
    if(responseData.status === "OK"){ 
    this.setState({ 
     data: { city: responseData[0].destination_addresses[0].rendered,duration: responseData[0].rows[0].elements[0].duration.text.rendered }, 
    }); 
    }else{ 
    // Do something 
    } 
    }) 
    .done();