我如何在React Native中解决uniqe关键道具问题

Question

I have React Native project and when i try to build my phone, i'm getting this error message. Warning: Each child in an array or iterator should have a unique "key" prop. But it works on computer emulator.

Here is json data: http://hazir.net/api/match/today

and here is my codes,

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

export default class Matches extends React.Component {

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

  componentDidMount(){
    return fetch('http://hazir.net/api/match/today')
      .then((response) => response.json())
      .then((responseJson) => {

        this.setState({
          isLoading: false,
          dataSource: responseJson,
        }, 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.matchId}, {item.matchDate}</Text>}
          keyExtractor={({id}, index) => id}
        />
      </View>
    );
  }
}

Answer 1

The easiest solution would be to update your keyExtractor as it appears to not be working. It doesn't look like your data has an id property, however it does have a matchId property. This means you could do something like the following.

<FlatList
 ...
 keyExtractor={({matchId}, index) => matchId.toString()}
/> 

Alternatively you could use the index as the key and do this

<FlatList
 ...
 keyExtractor={({matchId}, index) => index.toString()}
/>