How can I customize the Android notification on React Native?

To customize the notification display and behavior, consider using a plugin called react-native-push-notification which allows granular configuration of Android local notifications. There is no need to configure or use the remote push notification aspects of this package.

Example code to issue a custom local notification:

PushNotification.localNotification({
    title: "My Notification Title",
    autoCancel: true, 
    message: "My Notification Message",
    bigText: "My long message goes here",
    vibrate: true, // (optional) default: true
    vibration: 300, // vibration length in milliseconds
    playSound: false // (optional) default: true
});

Import the plugin and replace the following line of code in your Pushy.setNotificationListener() with the relevant invocation of the plugin:

Pushy.notify(notificationTitle, notificationText);