React Native FlatList with object

Question

I want to render object with React Native's FlatiList but this component doesn't return the expected result. My dictionary is like this:

Object {
  "Lisa.Sky": Object {
    "name": "Lisa",
    "surname": "Sky",
    "age": 21,
    "sex": female
  },  
  "Thomas.Prat": Object {
    "name": "Thomas",
    "surname": "Prat",
    "age": 33,
    "sex": male
  },  
  "Paul.Sing": Object {
    "name": "Paul",
    "surname": "Sing",
    "age": 88,
    "sex": male
  },
  "Andrew.Brown": Object {
    "name": "Andrew",
    "surname": "Brown",
    "age": 23,
    "sex": male
  },
}

I have implemented a FlatList like this, but I have white screen

   <View>
       <ScrollView>
           <FlatList
                data={this.props.nameList}
                renderItem={({item}) => 
                    <View key={item.name + "." + item.surname}>  
                        <Text style={styles.viewDetail}>{item.name}</Text>
                        <Text style={styles.viewDetail}>{item.surname}</Text>
                        <Text style={styles.viewDetail}>{item.age}</Text>
                        <Text style={styles.viewDetail}>{item.sex}</Text>
                    </View>
                }
                keyExtractor={(index) => index.toString()}
           />
       </ScrollView>
   </View>

Thanks

What is the result of your code? – aseferov Jan 11 '19 at 09:15 — aseferov, Jan 11 '19 at 09:15
I have a white screen. renderItem is never called – zp26 Jan 11 '19 at 09:20 — zp26, Jan 11 '19 at 09:20

score 33 · Accepted Answer · answered Jan 11 '19 at 09:42

you can do like this way. check working snack. https://snack.expo.io/@nazrdogan/bad-cashew

import * as React from 'react';
import { Text, View, StyleSheet, FlatList } from 'react-native';
import { Constants } from 'expo';

// You can import from local files
import AssetExample from './components/AssetExample';

// or any pure javascript modules available in npm
import { Card } from 'react-native-paper';
var obj = {
  'Lisa.Sky': {
    name: 'Lisa',
    surname: 'Sky',
    age: 21,
    sex: 'female',
  },
  'Thomas.Prat': {
    name: 'Thomas',
    surname: 'Prat',
    age: 33,
    sex: 'male',
  },
  'Paul.Sing': {
    name: 'Paul',
    surname: 'Sing',
    age: 88,
    sex: 'male',
  },
  'Andrew.Brown': {
    name: 'Andrew',
    surname: 'Brown',
    age: 23,
    sex: 'male',
  },
};
export default class App extends React.Component {
  render() {
    return (
      <View style={styles.container}>
        <FlatList
          data={Object.keys(obj)}
          renderItem={({ item }) => <Text>{obj[item].name}</Text>}
        />
      </View>
    );
  }
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',
    padding: 8,
  },
});

This is a good solution! Do you cycle through the objects on each render, `Object.keys(obj)`? Or do do the FlatList do something tricky to avoid this? — Rasmus Knap, Jun 08 '20 at 09:46

score 4 · Answer 2 · answered Jun 11 '20 at 06:33

4

You can do it by

<Flatlist 
   data={Object.values(obj)}
   ...
  />

answered Jun 11 '20 at 06:33

Sjonchhe

790
8
16

score 2 · Answer 3 · answered Jan 11 '19 at 09:24

2

According to documentation

For simplicity, data is just a plain array. If you want to use something else, like an immutable list, use the underlying

Try to pass data as array not object

answered Jan 11 '19 at 09:24

aseferov

6,155
3
17
24

score 2 · Answer 4 · answered Jun 08 '20 at 09:38

I got to this old post because I googled "flatlist react native support object" and in turns out - FlatList only supports array. But the underlying VirtualizedList do support object.

My data is structured by recommendations from redux:

const data = {
    byId: {
        0: { id: '0', name: 'Bill' },
        1: { id: '1', name: 'Steve' },
        2: { id: '2', name: 'Dan' },
    },
    allIds: [0, 1, 2]
};

And i need VirtualizedList to support this data structure

<VirtualizedList
// Use keyExtractor to help the list optimize performance
    keyExtractor={item => item.id}
    data={data}
    initialNumToRender={7}
    renderItem={({item})=> {
        return <Text>{item.name}</Text>;
    }}
// the virtualized list doesn't know how you want to extract your data
// you need to tell it
    getItem={(data, index) => {
        const dataIndex = data.allIds[index];
        return data.byId[dataIndex];
    }}
// it also needs to know how much data you have
    getItemCount={data => data.allIds.length}
/>

The difference between the FlatList implementation and the VirtualizedList is just you need to overwritegetItem and getItemCount

You can see full example here: https://snack.expo.io/@rcknti/virtualized-list-example

sdkcy · Answer 5 · 2019-01-11T10:32:47.520

You need to use your data as an array(If you need, you can check that from https://facebook.github.io/react-native/docs/flatlist#data ). Your data can be something like that,

const nameList = [
    {
        "name": "Lisa",
        "surname": "Sky",
        "age": 21,
        "sex": female
    },
    {
        "name": "Thomas",
        "surname": "Prat",
        "age": 33,
        "sex": male
    },
    {
        "name": "Paul",
        "surname": "Sing",
        "age": 88,
        "sex": male
    },
    {
        "name": "Andrew",
        "surname": "Brown",
        "age": 23,
        "sex": male
    },
];

React Native FlatList with object

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