Example of Infinite Loading Listview in React Native using FlatList

Paging in ListView

This is an Example of Infinite Loading Listview in React Native using FlatList. A React Native list view that supports infinite scroll. In mobile application development, ListView has a very important part as we use ListView in almost all applications. If we have to load a huge amount of data in a listview we have to use pagination for the seamless performance. A ListView with Load More Button in the bottom to load data can be an option but what if we load the data automatically when the user reaches the end of the list? This feature will give a good user experience to your application users.

What is pagination?

Let’s take a case where you can simply imagine what if Facebook loads all the Facebook posts from the Facebook database on your Facebook wall? Doesn’t it sound nasty? It will take hundreds of hours even more than that so what is the best way to load the data? Simply paging. When you open the Facebook they just show you 10-20 post and while you scroll the Facebook they load the next 10-20 posts in background. That is what the paging is.

In our example,

1. We are loading the first 10 posts from the web API call in componentDidMount.
2. While the user reaches the bottom of the list we call the Web API again to get the next 10 posts.

We are using a variable offset to manage the index on upcoming Data. We will increase the offset by 1 after the successful call of the web API so that when we call the web API next time we will get the next data-set. So let’s get started with the example.

To Make a React Native App

Getting started with React Native will help you to know more about the way you can make a React Native project. We are going to use react native command line interface to make our React Native App.

If you have previously installed a global react-native-cli package, please remove it as it may cause unexpected issues:

npm uninstall -g react-native-cli @react-native-community/cli

Run the following commands to create a new React Native project

npx react-native init ProjectName

If you want to start a new project with a specific React Native version, you can use the --version argument:

npx react-native init ProjectName --version X.XX.X

Note If the above command is failing, you may have old version of react-native or react-native-cli installed globally on your pc. Try uninstalling the cli and run the cli using npx.

This will make a project structure with an index file named App.js in your project directory.

Code for Infinite Loading Listview

Now Open App.js in any code editor and replace the code with the following code

App.js

// Example of Infinite Loading Listview in React Native using FlatList
// https://aboutreact.com/infinite-list-view/

// import React in our code
import React, {useState, useEffect} from 'react';

// import all the components we are going to use
import {
  SafeAreaView,
  View,
  Text,
  StyleSheet,
  FlatList,
  ActivityIndicator,
} from 'react-native';

const App = () => {
  const [loading, setLoading] = useState(false);
  const [dataSource, setDataSource] = useState([]);
  const [offset, setOffset] = useState(1);
  const [isListEnd, setIsListEnd] = useState(false);

  useEffect(() => getData(), []);

  const getData = () => {
    console.log(offset);
    if (!loading && !isListEnd) {
      console.log('getData');
      setLoading(true);
      // Service to get the data from the server to render
      fetch('https://abooutreactapis.000webhostapp.com/getpost.php?offset='
        + offset)
        // Sending the currect offset with get request
        .then((response) => response.json())
        .then((responseJson) => {
          // Successful response from the API Call
          console.log(responseJson);
          if (responseJson.results.length > 0) {
            setOffset(offset + 1);
            // After the response increasing the offset
            setDataSource([...dataSource, ...responseJson.results]);
            setLoading(false);
          } else {
            setIsListEnd(true);
            setLoading(false);
          }
        })
        .catch((error) => {
          console.error(error);
        });
    }
  };

  const renderFooter = () => {
    return (
      // Footer View with Loader
      <View style={styles.footer}>
        {loading ? (
          <ActivityIndicator
            color="black"
            style={{margin: 15}} />
        ) : null}
      </View>
    );
  };

  const ItemView = ({item}) => {
    return (
      // Flat List Item
      <Text
        style={styles.itemStyle}
        onPress={() => getItem(item)}>
        {item.id}
        {'.'}
        {item.title.toUpperCase()}
      </Text>
    );
  };

  const ItemSeparatorView = () => {
    return (
      // Flat List Item Separator
      <View
        style={{
          height: 0.5,
          width: '100%',
          backgroundColor: '#C8C8C8',
        }}
      />
    );
  };

  const getItem = (item) => {
    // Function for click on an item
    alert('Id : ' + item.id + ' Title : ' + item.title);
  };

  return (
    <SafeAreaView style={{flex: 1}}>
      <FlatList
        data={dataSource}
        keyExtractor={(item, index) => index.toString()}
        ItemSeparatorComponent={ItemSeparatorView}
        renderItem={ItemView}
        ListFooterComponent={renderFooter}
        onEndReached={getData}
        onEndReachedThreshold={0.5}
      />
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  footer: {
    padding: 10,
    justifyContent: 'center',
    alignItems: 'center',
    flexDirection: 'row',
  },
});

export default App;

To Run the React Native App

Open the terminal again and jump into your project using.

cd ProjectName

1. Start Metro Bundler

First, you will need to start Metro, the JavaScript bundler that ships with React Native. To start Metro bundler run following command:

npx react-native start

Once you start Metro Bundler it will run forever on your terminal until you close it. Let Metro Bundler run in its own terminal. Open a new terminal and run the application.

2. Start React Native Application

To run the project on an Android Virtual Device or on real debugging device:

npx react-native run-android

or on the iOS Simulator by running (macOS only)

npx react-native run-ios

Output Screenshots

Output in Online Emulator

That was the example of Infinite Loading Listview in React Native. If you have any doubts or you want to share something about the topic you can comment below or contact us here. There will be more posts coming soon. Stay tuned!

Hope you liked it. 🙂