React Native AppState – Active | Background | Inactive

React Native AppState

This is an example to Get Application State using AppState in React Native. React Native AppState helps you to know the currents state of the application. It will give you the information that the application is in the foreground or in the background, and will notify you on the change of state. AppState is frequently used to determine the intent and proper behavior when handling push notifications.

Different App States

React Native AppState will provide you the following different App states:

  • active – The app is running in the foreground
  • background – The app is running in the background. The user is either:
    • using another app
    • on the home screen
    • [Android] on another Activity (even if it was launched by your app)
  • inactive – This is a state that occurs when transitioning between foreground & background, and during periods of inactivity such as entering the Multitasking view or in the event of an incoming call

To Import AppState in Code

import { AppState} from 'react-native'

To add AppState Listener

AppState.addEventListener('change', this._handleAppStateChange);

In this Example, we will see how to know the application status using the AppState. So Let’s get started.

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

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

App.js

// React Native AppState – Active | Background | Inactive
// https://aboutreact.com/react-native-appstate/

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

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

const App = () => {
  const [appState, setAppState] = useState(AppState.currentState);

  useEffect(() => {
    AppState.addEventListener('change', handleAppStateChange);
    return () => {
      AppState.removeEventListener('change', handleAppStateChange);
    };
  }, []);

  const handleAppStateChange = (nextAppState) => {
    console.log('App State: ' + nextAppState);
    if (appState != nextAppState) {
      if (appState.match(/inactive|background/) 
            && nextAppState === 'active') {
        console.log(
          'App State: ' +
          'App has come to the foreground!'
        );
        alert(
          'App State: ' +
          'App has come to the foreground!'
        );
      }
      alert('App State: ' + nextAppState);
      setAppState(nextAppState);
    }
  };

  return (
    <SafeAreaView style={{flex: 1}}>
      <View style={styles.container}>
        <Text style={styles.header}>
          Application Status
          {'\n'}
          Active | Background | Inactive
        </Text>
        <Text style={styles.textStyle}>
          Current state is: {appState}
        </Text>
      </View>
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'white',
    justifyContent: 'center',
    padding: 10,
  },
  header: {
    fontSize: 22,
    fontWeight: '600',
    color: 'black',
    textAlign: 'center',
    paddingVertical: 20,
  },
  textStyle: {
    textAlign: 'center',
    fontSize: 18,
    color: 'black',
  },
});

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

Download Source Code

Output Screenshot

Android

      


iOS

            

Output in Online Emulator

That was the React Native AppState. If you have any doubts or you want to share something about the topic you can comment below or contact us here. The remaining components will be covered in the next article. Stay tuned!

Hope you liked it. 🙂

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