Question

我正在托盘化以使用apikey学习从服务器获取数据。我与此https://facebook.github.io/react-native/movies.json创建相同的文档。我的文档链接https://api.mlab.com/api/1/databases/ibrhmklnc/collections/kitap?apiKey=xRw1H6NNZZnyeZArU5L8oUoVcsFb6tpf但是我无法在代码中列出项目。




import React from 'react'; import { FlatList, ActivityIndicator,
Text, View  } from 'react-native';

export default class FetchExample extends React.Component {

constructor(props){
    super(props);
    this.state ={ isLoading: true}   }

componentDidMount(){
    return fetch('https://api.mlab.com/api/1/databases/ibrhmklnc/collections/kitap?apiKey=xRw1H6NNZZnyeZArU5L8oUoVcsFb6tpf')
      .then((response) => response.json())
      .then((responseJson) => {
        this.setState({
          isLoading: false,
          dataSource: responseJson.movies,
        }, function(){
        });
      })
      .catch((error) =>{
        console.error(error);
      });   }

render(){

if(this.state.isLoading){
  return(
    <View style={{flex: 1, padding: 20}}>
      <ActivityIndicator/>
    </View>
  )
}

return(
  <View style={{flex: 1, paddingTop:20}}>
    <FlatList
      data={this.state.dataSource}
      renderItem={({item}) => <Text>{item.title}, {item.releaseYear}</Text>}
      keyExtractor={({id}, index) => id}
    />
  </View>
);   } }

Answer 1

为什么要将空函数添加到setState？

Answer 2

这是API的完整响应

[
    { 
        _id: { '$oid': '5be7260efb6fc072d46759b5' },
        movies: [ 
            { id: '1', title: 'Star Wars', releaseYear: '1977' },
            { id: '2', title: 'Back to the Future', releaseYear: '1985' },
            { id: '3', title: 'The Matrix', releaseYear: '1999' },
            { id: '4', title: 'Inception', releaseYear: '2010' },
            { id: '5', title: 'Interstellar', releaseYear: '2014' } 
        ] 
    }
]

如您所见，API响应是一个数组。因此，为了获取电影列表，您应该将dataSource设置如下：

dataSource: responseJson[0].movies,

从mlab本地获取反应数据

2 个答案: